tubbs final finish bullets

[Shadow9mm]

So I bought a TC Compass in 30-06 the the gun was always filthy after shooting and hard to clean. It also had a somewhat short throat. I made the mistake of looking down the barrel with a bore scope and it had a lot of tool marks. I used the tubbs final finish bullet sytem, 50 bullets, 5 different grits, 1 rounds per grit with a cleaning in between.

In short, it did work, but not as well as I had hoped and not consistently throughout the barrel.

I only took 1 before, but the before was fairly consistent over the length of the barrel, a little better in some places than others, much better on the lands.

Before



After 1 and 2

[stagpanther]

Looks much better to me, especially at the edge of the grooves. The important thing is, does it shoot any better? I just bought some of their finishing packs for my worse-looking barrels.You say one round per grit--I thought the instructions say use all ten bullets per grit (unless your keyboard dropped the zero, which is what I figure since you say "rounds" )?

[std7mag]

It's a TC Compass.
The Final Finish isn't going to turn it into a Criterion, or Bertlien barrel.
Looks much better to me.
Shoot it & see what the results are.

[HiBC]

There are high,jagged peaks . There are deep valleys . You can knock the tops off the peaks and come up with plateaus.
That may be the best you can do. Plateaus are pretty good.
Its a mistake to think you need to remove the low spots.

The secret of a good polish is a good tool finish. You aren't going to transform a moderate cost production barrel into a Harry Pope work of art...unless maybe you are Harry Pope.

I have had a cheapo barrel with a smeared cheese tool finish that shot about

2.5 MOA +,getting worse as the copper caked up.....I figured I had nothing to lose,I rolled some cast 30-30 bullets in diamond mold polishing paste and shot about 20. Of course,I had my rituals around the process,salamander sweat,drumming,burning sage,etc.
It transformed into a near 1 MOA barrel that was not a bad fouler.

Not to argue with David Tubbs,I use all one grit,a Gesswein (IIRC) green # 9 diamond compound. Its really fine,but it cuts good.I forget the micron.

I'll guess maybe 1200 grit? or 900?
What I have learned about lapping fits is the larger grit cuts a greater clearance. Using the same diameter bullet,a 240 grit will lap a bigger size hole than an 800 grit. The bullet with the fine grit,if the bullet is the same diameter,will just rattle through the hole lapped with coarse grit.

Remember that if you lap a 1911 slide to a frame. If you start with 320 grit you are using approx .003 screen rocks. Some of the rock will embed in the softer material,and become a tooth that will be driven by the soft piece to cut the hard piece. Your 320 grit may cut .0025 to .003+ clearance all around,per side.

Now,you come back with a fine 900 grit,which will screen about .001. Some of the .001 embeds. Maybe it will cut .0006 to .001 per side clearance,all around.

The 320 already left .003 clearance. Your 900 has nothing to cut.

I lap a fit with my finish grit only. And with that grit size I can control my clearance size

I was not making barrels. General toolmaking

[Aguila Blanca]

Originally Posted by HiBC

I figured I had nothing to lose,I rolled some cast 30-30 bullets in diamond mold polishing paste and shot about 20. Of course,I had my rituals around the process,salamander sweat,drumming,burning sage,etc.
It transformed into a near 1 MOA barrel that was not a bad fouler.

Would you share the source of the diamond paste?

[HiBC]

Gesswein is top of the line stuff. Its not cheap.
This link will take you right to a tube of green # 9 diamond.
This is a place you can find about anything for mold and die finishing

https://www.gesswein.com/p-11732-ges...high-temp.aspx

Its been a few years,this "high temp" idea is new, Kerosene or alchohol worked as lube/fluid. A wet patch ever few shots might be good.Use the diamond sparingly. I might spread thin on a a hardened/ground parallel then roll the bullets in a sandwich between two parallels.Or,a couple of pieces of glass.

[wizrd]

If you're going to do this 'rolling your own' fire-lapping ammo, use the longest bullet you can, and used a reduced, lower powder load.

[HiBC]

I was doing a 30-06. I used approx 170 gr 30-30 cast bullets loaded to 30-30 levels. It worked for me.

Another approach I might use is order the Tubbs bullets,just order a bunch of the fine grit. Skip the grit progression. No coarse grit.

I concede,I can't shoot with David Tubbs. But I did spend decades building and finishing steel plastic injection molds.

When my employer sent me to understudy a Master Mold and Die finisher,he was working on some coining dies for a Mint.

I have polished tungsten carbide mirrors used in satellites for optic control circuits. I know some about lapping and polishing while holding form and dimension.

I'm not a barrel maker. But I have successfully improved a button galled cheap barrel.

[logeorge]

HiBC: What you're saying about grit sizes makes sense to me. Never thought about it that way! I was a toolmaker/template maker, not a die maker, so have little experience polishing for fit, but it makes perfect sense that a large grit is going to cut more clearance than a smaller size. I have a barrel that tends to copper foul badly. When I get a chance I'll try your method to see if it helps.

[Unclenick]

It's complicated. The standard grades of abrasive have a pretty wide particle size distribution. As I understand it (HiBC, please correct this if you know otherwise) this has two possible effects: When your lap is fairly hard and the work is equally hard or softer, the big particles make big scratches. When your lap is soft, like a cast lead bullet against steel, the big particles tend more to embed in the lap rather than scratch up to full diameter, but another problem still exists, and that is the fine particles at the small end of the mix packing around the bigger particles and slowing their cutting action down.

I read some years ago about amateur telescope makers in the UK figuring out laboratory-grade abrasives that have a narrower particle size distribution cut twice as fast as the standard grade. In that instance, the work is hard (a glass mirror blank) and the lap soft (usually cast pitch). The NECO firelapping kit also uses laboratory-grade abrasives. I am unaware of any others that do. I can say the NECO kit makes fairly quick work of things.

[HiBC]

The Gesswein supplies are very high quality. I can assure you,if you work an EDM finish mold cavity to a flat,distortion free mirror finish,the tracks left by a stray oversize rock will tighten up your jaws!!
In my experience,lapping is about using the softer material as a matrix the grit particles embed in. The soft material drives the grit and cuts the hard material.

At my trade I typically used brass or cast iron laps. My two main power tools were a profiler and what looked like an overgrown Foredom on steroids.
Its 1/2 hp 10,000 rpm with a 1/4 in collet,and reducer collets.
The profiler is pistol shaped. A 0 to 14,000 rpm drive cable enters where a magazine would. Up top,where the breech would be,is a zero to 6mm variable eccentric,so I can apply a zero to 6mm eccentric stroke to a barrel,pointing like a gun barrel,out the front. I can clamp stones in it,or drive a lap with it.
The lap will float on the workpiece like a dustmop. My right foot runs speed control. So I have up to 14,000 reciprocal strokes a minute.

The rotary tool drives a sisal end brush or felt wheels.

Gesswein makes pretty good polishing stones,but they are sintered. Pressed and baked. While ther grit may be true,they can drop a clump,and that digger can spoil your work.

We used puddle stones. High grade grit is sifted into water. It settles out and become much like a japanese water stone. I'd saw my stones out of a block.

I think you are right,the bigger rocks get the cutting done,smaller rocks are clutter.They dont engage much. And,like a hard Arkansas stone,steel can clog things up. We used mostly a version of kerosene to maintain a proper slurry.
Too wet wastes diamond. Too dry...sort of galls.

I'll see if can find anythng n youtube

[Longshot4]

My Savage 10T in 6mm CM had a rough bore. When cleaning it I could feel the roughness. I had properly broke in with the shot, clean, shot ,clean...method. I noticed it had a lot of copper fouling. not at all smooth as other rifles I own. The rifle shot good but nothing to wright home about. I decided to take a chance with The 50 pack of lapping bullets from Tubb. The rifle is very capable now of one hole groups. I didn't get much shooting in with it before I Tubbed it. Although I can tell you that now it is capable of shooting house flies off White paper at 100 Yds. with consistency. And I'm not blowing smoke. Just telling it like it is.

[Shadow9mm]

Quick update, finally got a few minutes to check some measurements and start working up my loads again. It pushed the lands forward by about 0.028". I am actually happy with this. With the 150g Hornady Interlock BT bullets I was using, even seated 0.010 off the lands, the canalure was inside the neck and not visible. This should give me a little breathing room to load a touch longer.

[Unclenick]

Wow! 0.028"? The barrels I've firelapped haven't moved a tenth of that distance. Makes me wonder, based on your description of how the Interlock fit, if you were maybe using the Hornady type gauge with the bullet and got it in slightly cocked. I've had that happen. The result is a false short reading. The solution I've found is to hold the gun muzzle-up on a bench and to slightly wiggle the gauge back and forth as it goes in. I can then frequently feel it catch and slip past then hangup point.

[stagpanther]

@ shadow Maybe you used throat maintenance bullets instead?

[Shadow9mm]

Originally Posted by Unclenick

Wow! 0.028"? The barrels I've firelapped haven't moved a tenth of that distance. Makes me wonder, based on your description of how the Interlock fit, if you were maybe using the Hornady type gauge with the bullet and got it in slightly cocked. I've had that happen. The result is a false short reading. The solution I've found is to hold the gun muzzle-up on a bench and to slightly wiggle the gauge back and forth as it goes in. I can then frequently feel it catch and slip past then hangup point.

I took five measurements each time and averaged them, the measurements were fairly consistent from test to test. I generally did 3 pushing the bullet forward and wiggling the gauge. and 2 seating the bullet out far and letting it get pushed back into the case. I had the bullet get stuck a couple times generally a good tap on the stock would get it out, but I did have to get the cleaning rod out at least once in the before testing.

yes using the hornady case gauge and ogive bullet comparator tool.

[Shadow9mm]

Originally Posted by stagpanther

@ shadow Maybe you used throat maintenance bullets instead?

nope, just the regular final finish

http://www.davidtubb.com/final-finis...-bulletkit-308

[stagpanther]

I just got back from firing the final 10 #5 Tubbs final finish bullets through my 338 lapua magnum in cold windy conditions at 342 yds. I was pleasantly surprised that the first 4 shots including the 1st cold bore shot made a tidy little group right next to the bulls. It went downhill fast after that--I assume because the crud was building up fast in the bore. I don't even know what bullets they are.

[Shadow9mm]

Nice! Did you measure before? really curious to see if the results were similar in your gun. Also, I did notice that my gun cleaned a LOT easier after. What 338 do you have?

[stagpanther]

Nice! Did you measure before? really curious to see if the results were similar in your gun. Also, I did notice that my gun cleaned a LOT easier after. What 338 do you have?

I didn't measure--I assume the lead to lands is what you are referring to--but I can tell you this--I just finished cleaning the bore and upon closer examination there is an obvious wearing down of the lands into the rifling as you describe, though I can't say for sure how much it has changed. My guess is the wear may possibly be due to concentricity correction of the bullet as it transitions down the throat judging from the unevenness of the wear at the beginning of the rifling--at least in my bore. It's a savage 110 LRH 338 LM topped by a Leupold Mark 5 HD 7 x 35.

[Shadow9mm]

heard good things about the savage 338s, and that is a NICE piece of glass. I am assuming you bore scoped it is you were looking at the lands. How did it look for your rifle? Mine was an improvement, but not as much as I had hoped, and not as even over all as I had expected.

[stagpanther]

I am assuming you bore scoped it is you were looking at the lands. How did it look for your rifle?

Yes, I used a borescope the lead into the lands you can see the rifling tapers off into uneven lengths to the freebore, and the ends are arrow-shaped as opposed to right-angled. I'll try to get a picture.

[Shadow9mm]

Originally Posted by stagpanther

Yes, I used a borescope the lead into the lands you can see the rifling tapers off into uneven lengths to the freebore, and the ends are arrow-shaped as opposed to right-angled. I'll try to get a picture.

very interesting

[Unclenick]

That description is odd. I'd like to see a photo, too.

[stagpanther]

I just took a closer look at the lead to lands in my 300 Weatherby mag which I also finished with 10 shots of #5 tubbs today--some of the groove ends look "erased."