Just seeking opinions on how much of a difference there is between the two. I have read good things about the Tubbs system improving group size. I imagine it would be pointless to accurize a gun and pass on the barrel lapping because it was homemade.
Barrel Lapping vs. Tubbs Final Finish
- Thread starter kfrye
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A chambered and crowned barrel cannot be hand lapped without enlarging the diameter of the crown end which will destroy accuracy.
The best lappers with the barrel mftrs cannot do it, so no way an individual or local smith is going to be able to do it.
That is why all the mftrs AFTER lapping normally make a cut or mark on the end of the muzzle end of a new blank to tell you where to cut it off to get rid of that enlarged part.
Now Tubbs Final Finish works extremely well normally. However, I never fire all 10 of the shots with the largest grit normally. I normally fire 5 and then 5 of the subsequent sizes. After that I retest groups and cleaning. If I have to then I repeat, but never had to do it yet on at least half dozen guns.
BH
The best lappers with the barrel mftrs cannot do it, so no way an individual or local smith is going to be able to do it.
That is why all the mftrs AFTER lapping normally make a cut or mark on the end of the muzzle end of a new blank to tell you where to cut it off to get rid of that enlarged part.
Now Tubbs Final Finish works extremely well normally. However, I never fire all 10 of the shots with the largest grit normally. I normally fire 5 and then 5 of the subsequent sizes. After that I retest groups and cleaning. If I have to then I repeat, but never had to do it yet on at least half dozen guns.
BH
mindcrime
Well-Known Member
I bought the NECO fire lapping kit, and used it on a Remington Sendero in .300 Win Mag that I used to own. It DID reduce my group sizes and more importantly, it made cleaning the barrel MUCH easier. I would recommend it for ANY non-Precision barrel. David Tubb's kit, if I'm not mistaken uses Neco's lapping compounds.
lightbulb
I tried lapping a Rem 700 factory bbl with JB compound, and it did nothing. Just finished with Tubbs Final Finish. I followed instructions, did the entire treatment and now it cleans nicely, very smooth and no bluing, but accuracy has not changed at all.
Michael Eichele
Well-Known Member
FYI,
JB was never designed to take the place of lapping. Polishing yes, lapping no. It may be considered a 'lapping compound' but it is too fine to cut and remove imperfections and smooth out tooling marks. Note that there is a big difference between smoothing out rough metal and polishing a metal surface. Hence the reason it did not work for your purposes. If anything, too much JB (even a little is too much IMHO) actually makes copper fouling worse due to the bore being too polished.
Another FYI. I have talked with several barrel makers and they all have said that a barrel can be lapped after it has been chambered and crowned. Their tecnique is different thats all. The only issue with the crown is that the very sharp edge/finish of the crown gets damaged. Freshing up the crown by a few thousandths of an inch cures that. New barrels get fish mouthed at the end from lapping because they don't care about the end of a barrel that is over 27" long that is to be finished at 26". They just lap them without regard for the muzzle end. It would take too much time on the production line to take that much care of a new barrel.
I have used the .30 cal kit on a rifle that I discovered had a .298 bore. It had visible reamer marks and it was a bear to clean. It would shoot sometimes down into the .3's but often with fliers shooting longer strings.
After following the instructions to the letter the velocity drop was 150fps with a known load.
Shooting 11- 3 shot groups with Berger 210's there was not one flier and most all were nice triangle shaped,the smallest being .122".
There was no measurable lengthening of the throat and cleaning is much easier.
I am quite satisfied with the outcome.
Cliff
After following the instructions to the letter the velocity drop was 150fps with a known load.
Shooting 11- 3 shot groups with Berger 210's there was not one flier and most all were nice triangle shaped,the smallest being .122".
There was no measurable lengthening of the throat and cleaning is much easier.
I am quite satisfied with the outcome.
Cliff
Mikecr
Well-Known Member
I use Tubbs FF for barrel break-in, no matter factory or aftermarket barrels.
I also use his TMS now & then.
No problems, works good.
I have a lot of respect for the lapping completed by aftermarket barrelmakers. But they can't control the affects of finishing a barrel.
I also use his TMS now & then.
No problems, works good.
I have a lot of respect for the lapping completed by aftermarket barrelmakers. But they can't control the affects of finishing a barrel.
screech
Well-Known Member
elkaholic
Well-Known Member
Hi Cliff.....was that a Tubbs kit that you are referring to?.......Rich
Rich;
Yes it it was the Tubbs kit, 50 bullets in all. My goal in using it was to hopefully increase the bore diameter at the chamber, thus lowering pressures. The velocity drop would suggest that it did that. I now load a few more grains of powder to recover the lost velocity.
Cliff
Yes it it was the Tubbs kit, 50 bullets in all. My goal in using it was to hopefully increase the bore diameter at the chamber, thus lowering pressures. The velocity drop would suggest that it did that. I now load a few more grains of powder to recover the lost velocity.
Cliff
elkaholic
Well-Known Member
bamadawg2009
Well-Known Member
Im gonna jump in this late but, can you use the Tubbs kit at any time during the life of the barrel or does it have to be a brand new unfired barrel. I have a 308 that I built with a Adams and Bennett barrel ok go ahead and laugh but i built it on the cheap, but it will shoot 1" to .75s on a good day. The barrel does have a few rough spots in it and i was wondering if after 150-200 rounds down the pipe if it would be worth it to get a tubbs kit and try to get out the few rough spots in the tube?
