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Old March 5, 2018, 09:51 AM   #26
Yosemite Steve
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Actually, I need to try some fresh brass. All of my brass has been found to have crooked case heads from my Savage not having a square receiver face. It is true now but the brass is not. I think it's a big reason for inaccuracy.
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Old March 5, 2018, 10:36 AM   #27
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It will only be an issue the first time you shoot it. That will square the heads back up again, and the next reload won't see the recoil moment shift around and increase dispersion due to which side of the bolt meets the brass first. If you want better shooting from the first reloading, find which side of the head stick back the most and put that side on the same side of the chamber for each shot. It will reduce the effect.
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Old March 5, 2018, 05:40 PM   #28
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The guys hit on a lot of good points...

For me, 'Unfired' would be a good sign.
Unfired usually means a caliber change and not a bad barrel.
Even if the previous shooter didn't like the barrel, I ask what they were shooting.
Some barrels inherently don't like super light or heavy bullets, and some guys are just married to a certain weight or brand of bullet.

All Savage barrels I've ever owned shot reasonably to very well, I have no complaints.

Keep in mind that all production line barrels are made the same way, a broaching tool (cutting tool) is dragged through the bore to create rifling, and it's a crude cut at best.
I've never seen a common factory barrel that wouldn't benefit from hand lapping (forget fire lapping unless it's the last resort to save the barrel).
This is as simple as using an old brush, rod, some molten lead & some lapping compound, don't forget elbow grease!
There are 'High Tech' lapping heads, but they actually don't work any better than lead/brush method, you just don't have to melt lead.

The ONLY tool I recommend buying (and most serious shooters already have one) is a one piece rod with a ball bearing roller handle.
This allows the slug to twist with the rifling.
Otherwise, you will have to rotate the rod manually while pulling or the slug will unscrew on one stroke or the other.
Use a rod that is NOT capable of gouging the muzzle crown! This means the sectional rods are out the window, even the aluminum ones.
Polished stainless or coated rods work best...

Plug barrel with a patch, seat the old brush/rod on the patch, pour a small amount of lead on the brush.
Pull the rod/slug out and add lapping compound to the rifling grooves and reinsert.
Stick a fired brass in the chamber to protect chamber from overrun,
Work in long strokes, muzzle to chamber.

The finer the compound, the longer it takes, but the better the job will turn out.
It's amazing what an hour of lapping will do for the barrel in removing scratches, tool gouges & chatter marks!
I use an 'Exacto' knife to relieve grooves in the lead slug to protect the bore diameter, so the slug only works the rifling grooves.
This is VERY simple, easy to do & hard to screw up.

I'm fond of only leaving a few brass/bronze wires on the brush to center it in the bore, so the lead can grip the twisted wire at the core and allows lead to flow better around the brush.
An undersized patch end for your rod works also, but it's sacrificed and not junk like a worn out brush is.

If the slug quits cutting, no big deal.
Simply melt the lead off and repour with fresh lead or use another used brush, and if you choose, relieve the slug grooves again to maintain the bore diameter.

With a couple hours of lapping, and a few changes in slugs, you can get a near mirror finish.
Sure beats paying a barrel to extrusion lap a barrel that takes metal off everything, or coughing up to $350 for hand lapping!

That extrusion or fire lapping is just evil in regards to rifling edges and increasing center bore diameter since it cuts EVERYTHING...
You mostly want to polish the rifling grooves that are gouged up the most while leaving bore diameter and bore edges alone. A relieved slug does that, and if you find a choke or tight spot, you can work it exclusively instead of grinding the crap out of everything!

Last edited by JeepHammer; March 5, 2018 at 05:47 PM.
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Old March 5, 2018, 08:54 PM   #29
Yosemite Steve
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Thanks, JeepHammer. I may have to try that. My cleaned rifling looks awful when magnified. Or I may have to try it on the fresh takeoff barrel. We shall see. I'm curious to see how well it shoots with the bolt face being square to the bore for the first time.
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Old March 6, 2018, 02:35 PM   #30
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I don't have an 'Opinion'...
I have a bore scope & firing fixture.
Nothing like being able to absolutely PROVE your work produced results at the target.

Every barrel maker will 'Lap' the barrel for an extra charge.
If the rifling wasn't so crude in the first place, it probably wouldn't need lapping, but that's neither here nor there.

When the manufacturer advertises every barrel is lapped, that's usually an abrasive emulsion forced through the barrel instead of a proper lapping.
It takes EVERYTHING down, low spots that shouldn't be touched right along with everything else, and it's MURDER on the sharp edges of the rifling.

Machine lapping won't work a 'Choke' (restriction) down without working everything else that probably doesn't need aggressive work.
Your hand pressure will find those tight spots, and you can work them precisely by hand.

This is just a quick of the single pass broach cutting off the rifling...
As the broach is on a rod and pulled through the bore,
The broach is angled to cut the spirals.
When starting out, the broach is very 'Wobbly', it's trying to find it's equilibrium between the forces being applied to it.

This makes for a crooked track of the rifling cut, deeper & shallow cutting, gouging, etc. until the forces find equilibrium, then the cut smooth out quite a bit.
Better barrel makers cut this part off the blank, others cut the chamber in the worst of it, the 'China' made barrels might have this defect right at the muzzle since they don't care which end of the blank they chamber... (What do you expect from a barrel costing $12-$25 wholesale?)

The broach WILL chatter all the way down the bore, no matter how much lubricant used or how even the pulling force is applied, simply because it's trying to take a crap load of material off.
The broach tool WILL move from 'Side To Side' (round hole, so off center) creating high & low spots in the rifling.

Honing/lapping helps smooth out these issues. Since the slug is a constant size, it won't take as much off 'Low' spots as it does 'High' spots, and it will smooth over sharp edges & 'lips'.
Sharp edge lips (cutting edges) are a HUGE deal!
These shave off copper, copper liquified at these pressures, and a sharp edge will hydraulic out a crater in the barrel material.
Each round down range makes the pit/crater larger because more liquid/plastic copper is forced into that hole...

There is a reason people with a good bore scope recommend a PROPER & extensive barrel break in!
Keeping the copper cleaned out of that hole until firing blunts/dulls/rounds over that sharp edge keeps the pits/craters small enough they don't effect the strength of the barrel, and the barrel won't hide a clump of copper that can drop into the bore at any time.

Lapping is a Rapid Break In that rewards you every time you clean the bore!
The time I save cleaning copper alone is worth the two hours when I get a new barrel.

Keep in mind, before you lap a barrel, makes SURE all copper & lead is out of the bore!
Copper will keep your lapping from cutting in the correct shape or correct place.
It's common sense, but I've seen that cleaning skipped and the results weren't as impressive.
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Old March 6, 2018, 07:05 PM   #31
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JeepHammer, some of the process you described is hard for me to put together. How to make the lead plug on a brush and get it to lap only the rifling isn't intuitive via your description. I am very interested in trying this but I could sure use a detailed tutorial. Do you have any suggestions?
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Old March 6, 2018, 07:50 PM   #32
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It's not hard once you realize the slug is a NEGATIVE of the barrel.
What's a groove on the slug is the bore 'Land'.
You simply deepen the groove with an 'Exacto' knife and it doesn't impact your lands as much as the grooves of your barrel.

Also, keep in mind we aren't actually requiring the lead to try and cut the steel of the barrel.
The ABRASIVE is dragged in and out over the steel, wearing it away.
The 'Lands' of the SLUG will be in closer proximity to the GROOVES of the barrel, so the abrasive will cut more,
While the Grooves of the SLUG, deepened with trimming, won't be in as close of proximity, leaving room for abrasive to NOT cut as deeply or efficiently on the BORE lands.

Keep in mind the bore is the SMALLEST diameter, between LANDS in the barrel.
This hole is drilled, then reamed to size BEFORE the rifling is gouged into the barrel.
That drilled and sometimes reamed hole is MUCH smoother than the gouges left behind by the broaching tool that cut the rifling.
Smoother, and usually much more consistent in size, these lands don't need to be lapped as much,
These lands are what press, and sometimes cut the grooves into fired bullets, the bullet being a NEGATIVE of the barrel bore/rifling.

So, now to the type of bullet you are shooting...
Small bore, deep rifling, sharp edges get a serious grip on the bullet.
Thin jackets CAN be cut all the way through, and strip off the bullet in air resistance causing problems,
While thick jackets, hard lead will benefit from sharper edges and deeper rifling grooves.

Most time I try to do as little to the BORE (top of the lands) as is needed.
Once the bore wears out, the barrel is shot, nothing more you can do with it.

Deepening the rifling GROOVES slightly by lapping (polishing) isn't an issue,
There is a benefit to reducing friction, there is a benefit to uniform depth of rifling, there is a benefit to uniform width of rifling,
Lapping helps with all these things since the rifling was a rough gouge, not a clean machined surface.

Like I said, I don't have an opinion, I have a bore scope.
When you actually SEE how rough that rifling cut is, how uneven in depth & width it is, where the chips breaking off left sharp edges all over the place, burrs hanging off everywhere, you start to understand.
It's simply doing to the inside of the barrel (the business surfaces) as people do to the outside for looks only...
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Old March 6, 2018, 08:41 PM   #33
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So the lapping compound is just put into the bore? What if we put it into the lead?
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Old March 6, 2018, 08:51 PM   #34
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The Parker-Hale type cleaning jag, being undersized for the bore & having a bunch of grooves holds the lead the best.
When I find a restriction deep in the barrel that needs to be worked out towards the muzzle, I use a Parker-Hale jag to pour lead around.
You aren't going to pull the lead off a Parker-Hale like you might off scant brush wires,allowing you to work the restriction harder.

Common lapping, just to polish, the worn out bronze brush works OK, and we all have worn out brushes laying around in the way.
When you are done lapping you just toss the brush, but I usually try to recover the Parker-Hale jag with varying results. Melting the lead off works, but it takes a cold to molten melt since you can't drop a cold/moist lead coated jag into a hot lead pot unless you want 3rd degree burns and a lesson in water to steam expansion you will only do ONCE...
Cleaning lead off the ceiling isn't my favorite thing to do.

So I try to cut/chisel lead off the jag. Sometimes it's successful, sometimes I waste the jag...
If I were smarter, I'd just throw the jag in the lead scrap bucket for the next melt, but we all have our quirks and things we can't let go.

Now, as an example, I bought a Mauser 98 action in a poorly done Sporter stock with a .30-06 barrel when I was about 15 years old. Cost me $75 and was my first high power rifle.
Didn't shoot worth $15, which is probably why the guy sold it for $75...

A local retired gunsmith I sometimes worked for agreed to guide me as long as I did the work.
He found a 'Choke' about 5" from the chamber that was undersizing the bullets, meaning they rattled loose from that point to the muzzle.

I hand lapped that restriction out of that barrel, took me a week of free time (farm kid, not a lot of free time) and I probably went way too slow trying NOT to ruin the barrel.
Trigger job, properly drilled for optics mounts, mounts & rings properly installed, receiver squared, threads straightened, bolt face lapped square, barrel squared off & chamber set back, chamber recut & stock pillared & bedded,
(I had to wait for bedding resin to wear off my hands & grow out of my hair! I spent a week removing resin from the stock where I didn't intend it to be, just a total mess!)

I killed a white tail at 603 yds (according to my dad) the next fall.

You can't put metal back, so nothing I could do about the loose bolt, but the rifle shot on par with my grandpa's Rem 700 that was professionally set up.

That was the longest shot I ever made before joining the Marines at 17.
I'm not as impressed with the shot now as I was then, but I'm MUCH more impressed with the work done & the lessons learned than I was then...
I had no idea I would still be fixing other people's screwups 40 years later!

When I tell people how to do this stuff, they scoff.
People were shooting 1,000 yds long before any modern machine tools, tooling, CNC equipment, etc.
And the old ways may be modernized, but still basically the same functions/processes, and they still work...
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Old March 6, 2018, 09:29 PM   #35
Yosemite Steve
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Thank you for sharing all of this!
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Old March 6, 2018, 09:40 PM   #36
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Wheeler sold a bore lapping compound kit, something like 220, 340 & 600 grit jars for about $30 the last time I noticed them.
Brownells has a really nice set of jars, about 8 different grits that will cover 100% of machining/lapping you will do on firearms. (Good for making water pumps, etc flat so they will hold a gasket too!)

Machine tooling supply places will have bigger cans/jars, but you might need 3 grams, not a quart!
So the little jars go a long way when lapping optic rings, facing off receivers, anywhere you want to use friction machining instead of a cutting tool.
Once you learn to lap, you won't believe how handy a skill it is!

Keep in mind, if you want to make something flat, a piece of plate glass is dead flat and makes a good lapping surface.
Plate glass is floated on liquid tin, so gravity makes it dead flat.
Lay short carpet on a work bench, lay plate glass on the carpet, and lap away. Restores flat surfaces to what's supposed to be flat parts. I restore very old vehicles with a lot of fragile cast parts, lapping allows for safe restoration. Works the same for flat gun parts.
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Old March 6, 2018, 09:46 PM   #37
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No problem. Glad to do it.
You either spend a few bucks and learn to do any/every rifle you come across,
Or you pay someone else that spent $40-$50 on basic tools $150-$350 for lapping ONE BARREL.

Knowledge is a wonderful thing! Costs nothing to share and if people are willing, saves them a TON of money!
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Old March 6, 2018, 10:03 PM   #38
Yosemite Steve
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I have silicon carbide rock tumbling powder in 600, 400, 120/220 and 60/90 grits. I lapped my lugs by making a paste with the 400 grit and some gun oil. Do you think that would work for this?
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Old March 7, 2018, 08:24 AM   #39
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Abrasive is abrasive, I think it would work.
When I used dry powder I mixed it with petroleum jelly.
I think silicone is the base on the commercial stuff, it's sold as food grade lubricant since silicone is non-toxic, so it's easily available.
Yup, I just looked at the can and it's silicone binder.
A jar of vasoline stinks, and it dries out over time, but it's not like you are leaving it on after you are done and it's cheap, available everywhere.

I stay away from aluminum oxide abrasive.
Aluminum oxide is REALLY sharp, and for a polish abrasive it's HARD, has a tendency to imbed in the steel (and anything else you use it on).

I actually perfer silicone carbide, cuts VERY cleanly & evenly, so I would think you are good to go!

This is a machinist thing, it's super difficult to get a polish when the abrasive gouges & imbeds in the work piece.
It's cheap, but there are other abrasives that work better that aren't too much more expensive.
There is a reason Emery cloth is still made, it just works better for polishing & finishing than aluminum oxide.

I usually start out with a finer abrasive, if you find a spot that needs serious cutting, you can switch to a heavy cutter without remaking the slug.
You can go up in size, but not down. New, fresh slug for finer abrasive every time.
With modern barrels, you can start with about 320 to check for tight spots, and if you don't find one, 320 leaves a pretty good finish for break in.
Find a tight spot, you might want to work that spot with something heavier, but many times 320 will do it all.

You can go completely OCD, use 600 and get a super fine finish, but I can't see much of a point.
The idea is to leave a finish that is as true & fine enough the bullets finish it without issues.
Serious gouges are hard on bullets and continue to damage the barrel until you fire enough soft copper to round them over.
Round them over, or lap them out entirely in the beginning, and you bullets don't get damaged.
Nothing like raking a bullet over a file under extreme pressure and wondering why the bullets stray off all over the place, or undersizing a bullet in a tight spot and having it rattle loose down the barrel to the muzzle and wondering why they stray off...

This is personal preference...
I usually lap from the chamber. It's more difficult to do and you want to drill out a fired brass head so the rod/slug will fit through it. This protects the chamber.

By working from the chamber the barrel tightens as the bullet moves from chamber to muzzle.
If the barrel is in a receiver, this can be difficult for guys that can't remove the barrel correctly.
If you hit a really tight spot, working from the muzzle might be required, but be sure to protect the crown!
Re-crown isn't expensive or difficult, but it removes finish, and adds work/tools needed.
Lapping won't screw up the 'Throat' of the chamber if you keep the rod reasonably stright.

I use a rag on the rod, holding it in place with the 'Guide' hand, and I rotate the rag so it keeps wiping.
You get some play from the chamber, but from the muzzle you MUST keep the abrasive off the rod/crown contact.
Small bores are a pain in the butt, but .30 cal allows you some space for a rag or tape inside the crown for extra protection.
I find it easier to work from the chamber and NOT completely exit the muzzle.

Here is another tip, slip a pill bottle over the muzzle and tape it into place.
This will allow you a stop for the rod.
Duct tape on the rod for a depth indicator keeps you from overrunning your stroke.
When I find a tight spot, I tape the rod so while I'm working the tight spot I don't overrun it.

This is all common sense stuff, you will figure it out pretty quickly!
It can save a 'Bad' barrel, it can make most barrels easier to clean, it *Might* make a good barrel even better, but there is no guarantee, but I've never seen moderate lapping make a barrel worse.
Better barrel makers lap as a service to the customer, and if it didn't have benefit they wouldn't do that.
Since you are working with an abrasive so fine you need a micrometer or microscope to measure it, and the slug is a fixed size, you certainly aren't going to remove enough material to damage the barrel unless you go WAY overboard...

Try it, see what you think!

Last edited by JeepHammer; March 7, 2018 at 08:42 AM.
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Old March 7, 2018, 08:37 AM   #40
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Just as a side story,
The old (and I mean Moses old) gunsmith that got me started lived alone way back in the woods, so I checked on him from time to time.

I showed up, he was in the shop, which stank to high heaven! Made your eyes water! Stink you could taste!

He was polishing a receiver he had made, ran out of vasoline and used Vicks salve on a buffing pad!

I left laughing with clear sinuses!

This is the same guy that charcoal/bone case hardened/finished receivers in an old BBQ grill, and they were BEAUTIFUL! But he did it in the house garage in the winter, smoked everything up something terrible, but had GREAT results.

If you aren't making a mess, you aren't getting anything done!
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Old March 7, 2018, 12:58 PM   #41
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I think a couple of points need to be cleared up.

A rough bore has nothign to do with how it shoots, it may not clean easy, it may build some copper (usually not a lot), but it shoots fine.

As button rifling is a brute force method, there is no way its not going to leave a roguish barrel (it also induces stresses)

The stresses can be (and are) relieved more or less successfully. Probably the less part is why some never can be made to shoot.

Lapping cleans up the mess, after market barrel makers do some or a lot (Shilen is good, Lother Walther is good, Criterion is reported to be good) X Caliber is better than Savage factory but not as good as the others.

Savage factory still straightens crooked barrels (it works fine to not so much). Again a possible source of a bad barrel. You can tell those by how badly they bore sight.

After market guys don't mess with a crooked barrel, its scrap (one reasons costs are higher)

Savage does not sell factory barrels on the open market.

Cut rifles are better as they do not induce stress, the top barrel makers (Lilja, Bartlein) use that method. I believe it still needs clean up.

Hammer Forged makes very smooth barrels. It also induces huge stress. They used to be mediocre shooters.

If its loose mandrel (no finishing ) then its not the greatest shooter (think Military M16 barrels). Only the big mfgs use that (costly setup). Remington uses hammer forged, I believe Ruger does.

CZ I believe hammer forges then laps to a final size.

I don't know if Remington etc uses tighter mandrel tolerances but they have gotten pretty decent shooters now.

If the stress is not relieved in the relief process, you will get a wild shooting barrel.
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Old March 7, 2018, 01:03 PM   #42
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If you want a good clean and sub 1/2 MOA shooting barrel for the Savage, then a Shilen, LW or CBI would be a good way to go. You can get any profile you want.

I have a 270 pencil barrel that I have yet to get to shoot.

I think the issue with the pencils and button rifling is the major stress and the iffy relief doing that.

Originally when the button system came out, military and civilian barrel were a larger OD profile and less impact.

It also depends on if its a pull or push button.

Pencil Barrels: I can't help but think a push button makes for a poorer barrel.

Its advantage at the time was the speed you could make barres, particularly for the military.
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Old March 7, 2018, 02:20 PM   #43
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Steve,
For a time I earned my wages running a broach machine.I know something about broaches.
A broach is a CUTTING tool .You start it in an existing geometry in the workpiece,usually a hole.The broach has a series of teeth,each taking a small cut.Over the length of the broach,which is often one,or two,or three feet long,the original hole in the part is transformed to the desired geometry.
It might be a keyway in a pulley,a square,a hex,splines,etc.
They area great tool!
But they have a limitation . Each tooth makes a chip.That chip cannot escape via coolant flushing .Its trapped.
Each tooth on the broach has to have enough gullet to contain the chip for the entire length of the cut.
The broach is pulled through the work piece,so just like with a tap,you have to have a core of steel to turn the tap,you have to have a core of steel to pull a broach.
On a .308 caliber "broach",how large of a gullet can you grind in the broach for chip clearance?Not enough to pull through over 20 inches of barrel.

What happens when you pack up the flutes of a tap or reamer or drill or mill cutter? It breaks.

A broach is a wonderful tool,but chip clearance limits the length of cut possible with one.

Rifle barrels are not broach cut. I don't doubt a handgun barrel,such as a1911 barrel,can be broach cut.

The common method for most production rifled barrels and some excellent custom barrels is Button rifling. A very hard button with the desired rifling form and helix is forced through a finish reamed round bore. The button forms the steel,it does not cut. It makes no chips.

Cut rifling is an excellent method for making custom barrels.It cuts chips for the full length of the barrel.The difference from a broach is that chips can be controlled with the single cutter on the end of the mandrel.

Most of us are capable of learning a variety of skills,Steve,and I expect you could learn how to lead lap a barrel .
I do not think an internet thread is the place to learn.
I do not suggest you use a hard to afford barrel you want to shoot as a practice piece.
Actually,not just every fine rookie off the street can lap barrels for Lilja or Shilen or Krieger without some training and practice.

"A little knowledge....." and "Fools rush in..."

Note,for example,barrel makers sell barrels at a supplied length,but the recommend cutting 1 1'2" or so off and recrowning. Why is that?

Because the lapping will funnel the entry. Chambering takes care of it at the breech.

While I am not a great advocate of fire lapping,David Tubbs is not a moron.
If you need to do a little improvement on a production bore,fire lapping IS a viable DYI option.

Not all grit is created equal.Particularly in regard to grit size control.
There are grits the embed,grits that break down,etc.

Coarser grits cut more clearance,larger holes,than fine grits. And,they leave their own tracks.

I'm not a fan of grit progression,as in 220 to 600,or whatever. I'd use the finish grit.
If you decide to buy the barrel,shoot it. See how it does.

If you have to tinker, I have fire lapped a rough 30-06 barrel using cast lead 30-30 bullets and diamond mold polishing compound .Only one,very fine grit.

It became a very accurate barrel.
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Old March 7, 2018, 03:28 PM   #44
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A lot of good stuff up there, but a couple of corrections:

Quote:
Originally Posted by Jeephammer
Keep in mind that all production line barrels are made the same way, a broaching tool …
Actually, Remington, Winchester, Ruger, Sako and Steyr all hammer forge barrels from steel tubes hammered against a mandrel that has the rifling pattern in it. Hammer forging produces the least material waste of all the rifling processes and improves grain orientation and tensile strength of the steel. Military barrels are also frequently made this way (look for the CHF marking, as in Cold Hammer Forged). Here's a video on hammer forging from Daniel Defense. Savage uses button rifling on most of their barrels, though they also still had two single-cut rifling machines running some production when I toured their plant a dozen years ago. Button rifling, like hammer forging, introduces stresses in the bore, but the carbide buttons, which also make the rifling in a single pass the way a broach does, last longer and never need sharpening, so it's a low maintenance cost method.


HiBC,

The rifling broaches have a lot of space between teeth, which is where the chip goes. I don't know what the length limit is. Pyramid Air put up that article, so perhaps they use it or have it used on some of their barrels.


Quote:
Originally Posted by Jeephammer
Aluminum oxide is REALLY sharp, and for a polish abrasive it's HARD, has a tendency to imbed in the steel (and anything else you use it on).

I actually perfer silicone carbide, cuts VERY cleanly & evenly, so I would think you are good to go!
Actually, silicone carbide is harder and sharper than aluminum and embeds in soft metals, making it suitable only for steel and harder materials (like polishing rocks or rough cutting telescope mirror blanks, etc.). It it usually recommend for materials at Rc 55 and up you use nothing softer than silicone carbide, where aluminum oxide, being softer, is not recommended for anything above RC 54. Aluminum oxide cuts more slowly and doesn't micro-scratch the surface the way silicone carbide does. There is some information here. I've bought the calcined aluminum oxide mentions specifically for it being non-embedding. I have some Clover compound in aluminum oxide, and can attest to how much slower cutting it is. Brownells sells tight final fitting aluminum oxide lapping compounds and mentions specifically that they are non-embedding.


If you have a tight fitting lap in a bore, lands and grooves are cut equally by lapping with a cast lap or similar. I know someone who tried to change land-to-groove height ratios in barrels by lapping. He was in the Army and working as an armorer at the time and was able to spend weeks working at it, but the bores and grooves kept getting equally wider except for some edge rounding. This was working with cast laps.


I would be cautious that you know what your are getting with the Wheeler abrasive kit. The coarse abrasive (220 grit) can do some excessive scratching. The reason is that it is standard grade silicone carbide, which has a very wide particle size distribution. When Wheeler ripped off the NECO firelapping patent, they used 220, 320, and 600 grit, where NECO used 220, 400, 800, and 1200 grit. But that matching 220 grit coarse grade is not the same quality. NECO uses laboratory grade abrasive with a much narrower particle size range and that cuts roughly twice as fast (the result of having fewer fine particles packing around the larger ones) and also doesn't have the largest gouging particles in it. The 320 grit and 600 from Wheeler should be OK to use. There seems to be a defacto concensus that if you are going to use standard commercial grade silicone carbide compound to lap a barrel, 320 grit is where you want to go. The kit sold by Beartooth Bullets is an example and uses only 320 grit.
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Old March 7, 2018, 03:30 PM   #45
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A Broach is a high angle, heavy cut tool bit mounted on a guide mandrel.
High cut angle determines how the metal comes off.
Broach angles are considered chisels, breaking chips and separate metal along grain lines many times.
There is a reason broached surfaces often have to be finished to remove the damaged, grain split metal.
Broached metal leaves behind VERY sharp break off points, and they always are pulled up, snagging & gouging anything that contacts it.

It also leaves horrendous sides on any grooves it cuts.

It IS a brute force process and it's still commonly used in bigger bore barrel making.

As for cutting steps, depends on the depth of the total cut needed.
Since a broach can often cut 0.250" per stroke, some broach tools cut in steps.
As for being 'Long', again, depends on the cut being made...

-----

Now, like I said several times before, I don't have an opinion, I have a bore scope.
When I see a surface that would be better suited to a file, it's time to do something.
When I find a restriction/choke, it's time to do something.
I don't lap every barrel that I get my hands on, I lap the barrels that need it.

----

This might help you understand button rifling since it shows buttons.
http://dmetool.com/products/rifle-buttons-mandrels/

Better barrel makers use this process but it takes specialized equipment.
Lesser barrel makers use a broaching process since it takes little equipment to do.
China is an example, lots of broached barrels out of China, and if you buy a $299 farm store rifle, beware.

Properly done button rifling requires an extremely large, high force hydraulic press to pull that button through an undersized steel tube,
AND,
That hydraulic press needs enough force to keep that button moving at a consistent SPEED all the way through the barrel blank.
It's something a novice can screw up really easily since any starts/stops/speed ups/slow downs will cause hesitation marking (warbles/skewed) in the rifling.

I know how easily you can screw it up, I built, then rebuilt, then rebuilt the machine again to do it myself.

Buttons (Compression) barrels need to be stress relieved.
This can be hot or cold thermal stress relief.
Many lower priced firearms skip the thermal relief process, which is why cryo treatment often works with even used barrels.

A bright, shinny, new button makes for very clean rifling.
By the 400th barrel, not so much...
Again, lower end barrels have gouges, grooves, uneven rifling simply because the button is beat up, gouged, etc.
These barrels will benefit from lapping.


Keep in mind that either broach or button will NOT start in the bore, it takes some distance from start for the tool to equalize forces being applied to it.
Lesser quality makers don't want to scrap part of the barrel blank (waste), so they run a chamber reamer into the worst of it and call it good.
A top end barrel maker will cut the blank so all the bad rifling is removed by chamberings.
Again, a bore scope will show you if this has happened or not.

----

Hammer forging a barrel often uses a slug with rifling cut into it, the barrel material is literally hammered down onto that forming slug.
This is a FAST way to rifle, but it's not too refined and can leave the barrel bent so it needs to be bent back stright.
It also doesn't leave the sharpest rifling.

Modern versions use the same base process, but pull a broach or button through the bore to sharpen, straighten & uniform the rifling.

A big plus for hammer forging is it hardens the rifling & doesn't cut through grain lines in the barrel steel, so the rifling lasts much longer.

Its seen a resurgence with the introduction of super hot mag calibers which are hard on barrels.

When the M24 SWS rifle was being developed, Gale McMillen's R5 hammer forged barrel version outlived Remington's button rifled 6 groove 2 to 1 and that kind of kicked off the hammer forged barrels again, they had pretty much died off before that.
When the military required hammer forging, Remington had to buy new hammer forging machines, they didn't have one left.
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Old March 7, 2018, 03:46 PM   #46
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Just drilling barrels makes holes that are often not perfectly straight. All barrel manufacturers seem to have barrel straighteners on duty.
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Old March 7, 2018, 04:11 PM   #47
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There is one thing you folks seem to be missing...

You all reference upper end US manufacturers, not the low end market makers, makers import from the rest of the world...
The US is 13% of the world's population, and virtually every country has firearms/firearms component manufacturers.

I don't have issues with S&W, ArmaLite, etc, it's the 'Also Ran' farm store & discount gun store barrels I see a TON of.
When you can buy an AR style barrel for $12 when you buy a gross at a time, when they are $18 each when you buy a dozen at a time... You KNOW they weren't made in the US or by a known maker.

When I visited Remington some years back, receiver & barrel stock came in and got wacked off by a band saw. Not even a CNC saw, just a band saw.
Receiver tubing was stood up in an open tube grinding fixture, and the cut surface ground smooth, but all through the process the receiver blank NEVER got faced off square, the saw/grinder surface was all it got...
Which is why I pull barrels, lathe mandrel mount receivers, and cut a true/square surface for the barrel to mount up against.

Since the tubing is forced onto a tap to cut threads for the barrel, I lathe straighten threads.
You know, the way it was supposed to be done in the first place...?

Now, a CNC machine cuts bolt slots/openings in the receiver, why not add the squaring & threading to that CANC machining?
A human can force thread the receiver on a dull tap faster than a CNC can switch tooling and do the process? Your guess is as good as mine...

Nothing like finding a barrel the bore is off center to the outside profile.
That means the outside profile was cut before it was rifled!
Investment of time/labor in that barrel blank BEFORE the rifling was cut would encourage to NOT toss the barrel for bad rifling...

The best US maker I toured was Ruger.
While I might argue how they do things, it was all proper & in the correct steps.
Barrels reamed to bore size, rifled, chambers semi-finished, outside profile cut, threads cut while turning so they were concentric with the bore, finish chambering done after barrel was installed in the action with the bolt for that particular firearm.

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Old March 8, 2018, 03:05 PM   #48
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This is from Dan Lilja on making rifle barrel.

http://riflebarrels.com/the-making-of-a-rifle-barrel/

This is from Brux

http://www.bruxbarrels.com/gpage.html
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Last edited by old roper; March 8, 2018 at 03:21 PM.
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Old March 8, 2018, 07:22 PM   #49
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Drilling long deep holes is a crap shoot...
The best pilot holes for the bore come from LASERS.
Lasers aren't common, but some military applications require this type of accuracy.
I have had barrel bar stock piloted by a laser a couple times, it's expensive.

The 'Best' COMMON way is to drill the stock in as stright a line as possible, drill, ream, rifle,
THEN mount barrel between centers, cut outside profile centered on the bore.
When you start with barrel blank too thin it bends (Curls would be more accurate) when you drag a rifling tool through the bore, and when it's that thin, there isn't enough material many times to cut the outside profile matching the bore.
This produces an offset bore which drives me crazy since I have to cut new threads that match the bore, not the profile.

When you start with a large bar stock, drill, ream, rifle... Then cut outside profile to match the bore...
This provides a stright bore, a profile that matches the bore center, but creates a lot of waste & requires a lot of time, and a darn good lathe.
Trying to make a bent tube straight is a work around at best. Thin barrel blanks are cheaper and create less waste, require less machining, but buttons or broaching bends these smaller barrel blanks & they have to be straightened...

A 'Custom' barrel comes in a lot of flavors, I start with 1.5" or 2" bars (depending on caliber) sometimes pilot drilled, sometimes not.
You want a full on 'Bull Barrel', this is what you start with.
My best 1,000 yard shooter was a full 2" diameter weighed 35 pounds with a 5" wide laminated bench rifle stock.
Firing .300 Wearherby mags you could watch the bullets impact the target up to 300 yds.

I ALWAYS start with large diameter bar stock simply because it doesn't bend or curl when rifled.

Now, no one wants to pack around an ugly, 35 pound, .30 cal rifle, so bench queen only, but it would shoot!
I won't do it again, but it was an interesting experience.

We are going to have drilled bores, something dragged through the hole to create rifling for the foreseeable future, so knowing how to make the best of what we get on the common market is probably a good idea unless you have an unlimited budget. I don't so I'll be making the best of what I can buy or build...

Last edited by JeepHammer; March 8, 2018 at 07:30 PM.
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Old March 8, 2018, 09:04 PM   #50
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I always wonder about some poster that don't make barrels but know everything about them. I posted from online barrel makers and you find fault with them.

If you making barrel please your post site. Lilja been in business long time and Brux owners used to work for Obermeyer same as Krieger,Mike Rock, Rock Creek barrels) and some others.

Your the one critcizing so back it up with your site on making barrels.
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