Home Forums Hunting & Shooting Ask The Gunwriters MD & Charlie Sisk-Make homemade lapping compound

Hi Mule Deer and Charlie Sisk

IIRC, MD in the very near past commented that gunsmiths who lap barrels use a medium grit compound to lap gun barrels. However, what is the oil/petroleum
used to put the lapping grit into? Also, what brand of lapping grit do you recommend? Vaseline(HA) or what? I remember Mule deer said that too much lapping with Brownell's JB Bore Cleaner will make the bore too smooth and cause excess copper fouling. I wish to make a home made lapping compound as a project to keep me busy. Help from all and anyone is much appreciated.

roanmtn

How could a bore too smooth cause excess copper fouling ?

Think of dragster racing slicks. They get max grip, ie fouling on the concrete.

I'm not John or Charlie. A friend of mine that makes very high end barrels uses Clover 320 and 400 for final lapping. You need to be really conscious of what you're doing if you're going to do this. Use a quality, consistent compound that's formulatted for the job...not a home brewed slurry. The lead used for the lap is also important because of the amount of antimony.

Barrels that are too smooth can lay down copper like you wouldn't believe.

Good shootin' -Al

More contact between bullet and bore....

Agree on using lapping compounds that are made for that application.

I’ve read that some abrasives can imbed in the steel and cause excessive wear.

So a do it yourself formulation may not be a great idea without a lot of research.

I’d use a proven product.

DF

Well.... You all have convinced me to wait and do this a wee bit different. I'll hold off and do this right.

Resist the urge to use Cerrosafe to form your lap.

Well.... You all have convinced me to wait and do this a wee bit different. I'll hold off and do this right.

What problem do you have that lapping is to address?

The first thing to do is determine if the barrel has a problem that lapping might bring around. That's the purpose of the lead lap' plug...it lets you feel the loose or tight spots. Since lead is a dead material that retains it's shape, the art comes into play the very first time the plug goes up the barrel.

On the first one I did, it took a half dozen attempts to savvy what that barrel was trying to tell me. Also, some barrel makers leave a bit of a choke where the muzzle will be....that needs to be considered before just lapping away.

Seems one can potentially do more damage than good.

You can’t put it back. Taking it off, thus needs to be done with thought and purpose.

Barrel makers have their methods. I’d inquire, some may even tell you their secrets. Some may not.

DF

Definitely a solution seeking a problem.

I dont recall using any lapping compound on a bore. I have used JB bore paste, I guess technically thats a lapping compound. I can see how a person could f#&k this up more ways than a country boy could pick a banjo. And what is being accomplished ? If the bore is that bad, just take that barrel off and install another. Lapping barrels is as much art as it is science. Call a custom barrel maker and see how they do it. But then, I doubt they would say.
Will the lapping compound become ingrained in the surface ? I guess it depends. How will you know for sure if you get it all out ? If the barrel is that bad, does it even matter ? And what exactly will the finish be when its finished ? I certainly dont know enough about this to offer a useful comment. Other than "dont do it".
Charlie

Anyone have "luck" using David Tubb's kits, either loads or just bullets?

I bought the Tubbs bullets for a new Browning aBOLT Boss 30 years ago. Loaded up the rounds and polished the barrel. It shoots 1/4-3/8 all day with good loads. May not have made any difference... it shot .75-1.00 before I tried it with one load.

Marshall Stanton of Beartooth bullets had a lapping kit and a very well written how-to booklet that came with the kit.
A friend and I ordered the kit for our 44 Handi-rifles many years ago but I believe you could get the kit for about any caliber.
It seemed to work pretty well for us. Takes a lot of patience.

I've used the Tubbs kit, along with lapping compounds sold by Brownells, including JB compound. But if you use JB a lot in a decent barrel, it will over-smooth the bore's surface, and eventually result in heavier copper-fouling, due to the reason mentioned in one of my above posts: Too much bullet contact with the bore.

Have talked to a few barrel makers who offer lapped barrels. If I recall correctly, the finest grit any of them used was 600, because it left just enough striations in the bore to reduce bullet contact and result in less fouling.

That barrel maker is known for the lack of fouling in his barrels, even during the "break-in" process. I have several on my rifles and don't remember installing DBC in any, because they didn't copper-foul much at all--and the little that appeared was easy to remove with typical solvents. (He also warns against using JB Compound more than occasionally in his barrels.)

Have used lapping bullets to "refresh" the chamber throat in barrels that have been shot a lot. This can definitely restore accuracy at least somewhat. A good example is the factory barrel on the heavy-barreled Remington 700 .223 Remington purchased new around 20 years ago, which was used for a lot of prairie-dog shooting. It would usually group five shots of just about any factory ammo into less than 1/2" at 100 yards, and do even better with handloads. It would also shoot just as accurately after 500 rounds without cleaning.

But after a few years, 5-shot groups with factory ammo started opening up to closer to an inch, which my Hawkeye bore-scope revealed was due to a couple inches of "gator-skin" in the rifling in front of the throat, and the . So I fired some lapping bullets made with the kit offered by NECO, until the Hawkeye showed the gator-skin was gone. Groups with good factory ammo weren't quite as small as when the rifle was new, but stillaveraged right around 1/2", so I also installed DBC. The rifle's still grouping very well, with a long time between cleanings.

Have also hand-lapped some rough factory barrels with coarser-grit lapping compounds from Brownells, which usually helped. But it's a PITA, and simply installing DBC generally works as well, if not better.

I’ve used automotive polishing compound for many years. Cheap, effective…..but slow. Slow because, it is an extremely mild abrasive. So far, it’s only improved rifle, and a Contender .223 Rem., performance!

Maybe, I’ve just been lucky! 😉 memtb

Sometimes you can take the whole "Look at what I did myself" thing too far.

When it takes too much time, too much money, produces inferior results,
or risks more than what it can save, that's a good indicator that you shouldn't.

https://www.gun-tests.com/accessories/barrel-firelapping-revisited-beartooth-bullets-kit-examined-2/

I've used it a few times with "problem" barrels and accuracy either stayed the same or improved.

Beartooth Bullets is defunct, but other options are out there. YMMV. Not a gun writer.