tubbs final finish bullets

[stagpanther]

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

As you wish.

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

I obsess much more about the last few inches of the barrel than the first few.

[HiBC]

Interesting pix.

You do whatever pleases you.
For myself,I don't look at firelapping as a routine project to do on new rifles.

I don't know,Mr Tubbs might.

If I'm satisfied a barrel shoots good enough for my purpose,I leave it alone.

I would not firelap a good custom barrel. The one I did was a "bargain" Brownells pre-thread.pre-chambered for around $100.

Looking in the muzzle with a loupe,I could see reamer marks across the lands and button gall marks that looked like smeared cheddar cheese.

And all of it would clog with copper. And,it didn't shoot well.

I shrugged,figured I was stupid to buy a cheap barrel,also figured I had nothing to lose. I couldn't hurt it.

Bore scopes are cool. I don't have one. My measure of success was "Does it shoot?" In this case, accuracy improved so I was quite happy.

I look at it as a chance to make an otherwise junk barrel work.

If it does not work...Oh well!!

[Shadow9mm]

wowzas. That is really interesting. I will take some picks of mine when I get a chance. It looks like it took off 1 side.

Interesting note. the instructions say for a good barrel to skip # 1 and 2, I wonder how much of a difference it would make.

[stagpanther]

You do whatever pleases you.
For myself,I don't look at firelapping as a routine project to do on new rifles.

I agree with this. It's a judgement call and there is a balance of harmful vs good lapping that I take into consideration and none of my custom SS barrels need it at this point AFAICT. In the case of my recent savage barrels, even new they have enough what appears to me to be tooling damage at the last couple of inches to bore exit at the muzzle to make me want to consider using the fire-lapping.

[Longshot4]

I shot the Tubbs lap kit for my Savage 6mm CR. After breaking it in. shoot clean... The fouling was hard to remove and patches did not slice smoothly down barrel. So I Tubbed it. It's shooting about 1/2" at 100 Yds. I'm waiting to get some warmer weather to try a new bullet, powder and if I can find my CCI 4BR primers. I have a box of Burger 108 gr. pills to try.

[stagpanther]

I'm not jumping to any conclusions about that wear in the lead--could be all kinds of things going on that I don't have a clue about. My pet theory is that the lead is a "constriction area" for a bullet which is likely to be somewhat off concentric relative to the bore as it is "squeezed" to the lands (?). Another guess is that the rifling cutter may have some "drift" in the initial cut depth due to taper of the lead (?) so the lapping action may be actually be making it more uniform (?). Beyond my pay grade and I invite the real experts to comment.

[HiBC]

Stagpanther: I;m not entirely certain I see the eccentricity you are talking about.
I suspect its not about the bore or rifling. More likely in the chambering.
Chambering reamers have a pilot that follows the bore.There are solid pilots and interchangable pilotsSolid pilots are the dia the reamer maker ground them.Bore dias vary some.A pilot might be a little loose.

Reamer holding setups vary.I don't know how production rifle chambering goes.
Could be our person shows up to work and gets a basket of 100 barrels to chamber.Time is money. I indicate the bore true on both ends to within a couple of tenths TIR.
Suppose our person making production rifles does? I suspect he/she relies on chucking the OD.

[Shadow9mm]

Originally Posted by HiBC

Stagpanther: I;m not entirely certain I see the eccentricity you are talking about.
I suspect its not about the bore or rifling. More likely in the chambering.
Chambering reamers have a pilot that follows the bore.There are solid pilots and interchangable pilotsSolid pilots are the dia the reamer maker ground them.Bore dias vary some.A pilot might be a little loose.

Reamer holding setups vary.I don't know how production rifle chambering goes.
Could be our person shows up to work and gets a basket of 100 barrels to chamber.Time is money. I indicate the bore true on both ends to within a couple of tenths TIR.
Suppose out person making production rifles does? I suspect he/she relies on chucking the OD.

if you look at the rifling, relative to the throat, the left side of a land is higher up into the more than the right.

I suspect this is from the twist....if the bullet is rotating the pressure would no only be forward, but down on the side of the lands as well as the bullet was forced to rotate.

[stagpanther]

Here is a pic of the lead in an unfired savage 308 barrel I pulled off a donor rifle. It looks to me like a pretty clean, well-defined transition from the end of the freebore. What I speculate happens is that the lapping bullets "rounds off" the transition from the freebore to lead, and any eccentricity of the bullet is what is adding to the unevenness in the beginning of the rifling groove which is "moved" up the bore (away from the chamber) and gives the ends that distinctive arrow look.

[Shadow9mm]

So I have a new theory. I think rather than pushing the lands back, it reduced their height, which allowed me to seat bullets farther forward before hitting resistance. I am note sure how I feel about that though.

Some of the start of the lands seem to have been tapered more than others

Also you can see the flattened ramp where the lands start that is highly polised transition into the top part of the lands that are polished, but you can still see the horizontal tooling marks under and on the sides.

Land not pushed back, you can see it is right near the throat


a land that is pushed back, also note the taper compared to the one not pushed back


And finally a transition. also note, it made little to no difference in the grooves as they still have heavy tooling marks

[Shadow9mm]

So a quick update. I contacted Tubbs, it was a form on their website. They e-mail back and said to call them, let a number and said to ask for Bryan, who can "help me with my questions and issues". gonna call tomorrow.

[stagpanther]

So a quick update. I contacted Tubbs, it was a form on their website. They e-mail back and said to call them, let a number and said to ask for Bryan, who can "help me with my questions and issues". gonna call tomorrow.

Feel free to mention my interesting results--but keep in mind I have not in any way found evidence that the treatment has been detrimental to the performance of the rifle (yet, anyway). I hope to start developing loads soon to see what effect may have been made.

[Shadow9mm]

Originally Posted by stagpanther

Feel free to mention my interesting results--but keep in mind I have not in any way found evidence that the treatment has been detrimental to the performance of the rifle (yet, anyway). I hope to start developing loads soon to see what effect may have been made.

will do. I have not been able to get to the range to accuracy test yet, got the covid (almost better, ended up being just a real bad head cold with chest congestion) and have been stuck in the house. I am free tuesday and going to the range wednesday if the weather is even 1/2 way reasonable.

I will post again when i get testing done, let me know how yours goes. I'm just curious to see if they say these results are within the normal range.

[stagpanther]

Maybe ignorance is bliss--I probably wouldn't have felt motivated to do the fire-lapping had I not seen the damage--or let's call it "more chatter than normal"--especially that deep gouge. I'm still wondering what causes that pitting near the muzzle in my savages--like the barrel was dipped in something after the bore work was done?

[Unclenick]

Stagpather,

That's a new one on me. It that unevenness uniform all around? If it is only on one side, the off-center chambering reamer explanation could explain it. If it is all around, I'll guess the grooves are not even in height across their width. You can test that by slugging with a pure lead ball or cast bullet and measuring it with a micrometer.



Shadow 9mm,

In your images it appears to me the throat angle may have been flattened some. There are cleanup marks in the middle of your grooves, but they are absent from the floor of the grooves as they approach the corners of the lands. This is common lapping with jacketed bullets as the lands indent the bullet surface but don't really cut it, so you get a radius on the jacket where it comes off the engraving mark. That part of it is not touching down in the groove to remove the tooling marks. Lapping with cast bullets leaves less of that untouched area. Look for higher pressure loads than you used with the Tubbs kit to fill the bore better and to possibly leave copper streaks where the groove cleanup stopped.

Not using coarse abrasive on a good barrel is common sense. If it was an air gauged button-rifled and stress-relieved blank like a Douglas, then you won't have constrictions to remove, so all you need is to polish enough that it can't grab copper anymore.

Constrictions can be a big issue, especially for shooting cast bullets. A button-rifled barrel that wasn't stress-relieved before contouring will be narrower where the contour is thickest, and you need some cutting action to bring it up to the diameter of the muzzle. The last military barrel I firelapped was in a Garand and was 0.0003" narrower near the chamber than at the muzzle, and to shoot cast bullets well, that constriction had to go. In the end, the cast bullets took 0.0005" off the throat diameter and about 0.0001" off the muzzle diameter.

Nick

[Bart B.]

Unclenick,

I'm not aware of any military arsenal made Garand barrels that were button rifled. They were all broach rifled after being profiled or contoured as far as I know.

Those made at the end of the broach life had the smallest groove diameters and were the most accurate.

[stagpanther]

It that unevenness uniform all around?

Yes. I did not, however, seat the bullets any closer than what a standard COL at the lower powder charge recommended.

Sorry--I double-checked the remaining kits I have and all the bullets appear to be the same type (though I did get a .308 in the .338 kit). I was in error that there were different types of bullets across grit sizes.

I tried out the 280 AI barrel today with regular factory ammo, the results being rather poor (I suspect from the damage in the muzzle area), though I really wasn't expecting a miracle. The .338 LM I don't have any bullets smaller than 270 gr eld-x's (the Tubb bullets are 250 gr and look like matchkings) but will start with some lower power charges hopefully this weekend, though we are having some pretty unstable weather.

[stagpanther]

They e-mail back and said to call them, let a number and said to ask for Bryan, who can "help me with my questions and issues". gonna call tomorrow.

And?

[stagpanther]

I put new batteries into my Hawkeye--the pictures above were taken through my Teslong which does not have as high resolution as the Hawkeye.

Long story short--it's obvious I completely goofed up my interpretation of what I was seeing now that I have a much clearer picture! My sincerest apologies for misleading everyone, I didn't do it on purpose.

The long pointed black streaks the Hawkeye reveals are actually crud streaks to the sides of the grooves, the Hawkeye reveals the groove ends themselves are intact and even. Unfortunately I can't really get a good picture through the Hawkeye--that requires the skills of a heart surgeon using just a bracket holder.

Excuse me while I go have dinner--crow.

[RC20]

Funny that military rifles don't get special treatment lap wise and they shoot fine.

If it bothers you, buy a gun that is hammer forged. Those are smooth. They may not shoot for diddly but they sure are smooth.

Any cut rifled or button rifled barrel is going to look bad. Its how it shoots that counts.

All the lapping in the world is not going to make a poor barrel shoot good.

You want a clean barrel then get Carbon Killer 2000 (and the right procedure) and or Bore Tech Eliminators. I have WWI barrel that are bright. Look at them with a boro scope and you want to throw up.

You want a good barrel buy it from Shilen, Criterion, Bartlein etc. Tubbs is a shooter, he is not a metallurgist nor a barrel maker (Shilen does thousands of barrels and they know what works by combination of metallurgy and experience)

If the so called fire lapping makes one barrel better, it can make 10 others no difference or worse. Crap shoot.

A boro scope for a day in day out shooter is good for one thing, it tells you if you got it clean (see paragraph above - it still takes technique)

A gun smith uses a boro scope to asses barrel issues. He has the training and experience (hopefully ) to know what he is seeing.


I had one barrel you could feel the drag and was harder to clean. 500 rounds and can't tel the difference between it and the Shilen.

Nothing pretty about the WWII JA barrel but it shoots just fine. Probably only proof fired from the looks of it.

What works is a clean barrel and load development (and don't forget the shooter). There are no magic elixirs.

[stagpanther]

I haven't really had a chance to test the results thoroughly, though I did put some cartridges through the 280 AI and it still shoots like crap--but it did so before the fire-lapping as well as it has a very deep gouge right around the muzzle. My model 70 has a long spiral gouge, and I didn't notice any change at all with it after the treatment, so I guess that's also a "draw."

I was hoping to get a good test of my 338 lapua, but I only could sneak in a few shots between rain showers. Here's 5 shots of a low-end charge--93.3 grs of LRT driving a 270 gr eld-x at 235 yds; would have been a pretty nice group had I not pulled the shot a bit on the bottom. Hopefully faster charges will tighten that up. The barrel is definitely a lot easier and quicker to clean.



I've noticed the loopy 5 HD tends to "drift" the side focus dial a bit upon sustained shooting with the 338 LM, hopefully I can tighten that up just a hair.

[RC20]

I went through the Slick 50 craze. Years latter I became the designated facility engineer (no letter attached to the title) on machinery issues (well everything but that was my experience base)

What I learned was that magic elixer stuff does not exist for a reason for machinery anyway (won't comment on other aspect)

If you recall, there was this wonder stuff that you could treat the engine oil and then run it without oil and it would last hours and hours. Actually that part was true.

The Hammer was, it destroyed bearings in short order. How often do you loose all the oil in your engine? Ooops, guaranteed to destroy the engine though. Guaranteed loss vs no gain.

That was all based off WWII Aircraft engine research (no they did not figure it out themselves) based on Chlorine based oil. They had an abiding interest to see if you could get a plane home sans oil of course.

So, yes you could and you got a couple of missions before the bearings were destroyed.
A gain sometimes, 90% guaranteed loss.

As they usually got 500 -1000 hours out of an engine? Yep, pretty soon all your freighters are hauling new engines and no food, gas or ammo.

Slick 50 was not alwyas harmful but in the tight design engine (4 cylinders ) it could plug up the smaller oil passages. Yep, there goes your engine.

So, yes you can smooth a barrel out, that does not mean its going to do you any good.
If its does not shoot smooth is not the issue.

Smooth is easier to clean and if that is the goal, cool. I don't know you can wreck a barrel either (maybe if you really overdue it). Or you can shoot the barrel till its smooth and use the good cleaners.

If its a problem barrel you need a new barrel.

[Shadow9mm]

Originally Posted by stagpanther

And?

Got busy, sorry, will get it done tomorrow.

[Unclenick]

Bart,

Yep. I know. But this barrel was military (the one I got through the DCM ages ago) and it definitely had contour-corresponding bore narrowing. My speculation is the broach was getting dull and that stressed it, but I don't know for sure. War production can be hasty and drilling and reaming too fast would add to surface stress, too. All the other military barrels I've had were old club gun barrels that were so badly shot out I never considered doing anything but replacing them. Maybe I was too hasty. David Tubb seems to think you can bring a shot-out throat back with lapping bullets. Anymore, though, popping one of the Criterion barrels on is just too easy and saves a lot of time that might turn out to be a fruitless effort.

When NECO first developed their firelapping kit, they got a university smallbore team's rifles to lap, and IIRC, got no change in accuracy on about half of them and an average improvement of something like 15% reduction in group size with the other half. That pretty much echoes my experience with rifle barrels. About half the time it has no effect on accuracy and about half the time you get a modest improvement, and they are always way easier to clean afterward. Though, in the case of the Garand barrel, it stopped losing accuracy after 40 rounds, so I could get through a match with it. You could say it improved accuracy beyond that 40-round point but not before.

[Shadow9mm]

called them today. They said my results were odd and the barrel should be mirror polished unless the machining was super rough to begin with. Didnt really comment on the lands. Was able to send picks, Bryan said he would try to get back to me tomorrow on them.