Fire Lapping

[GregLaROCHE]

Has anyone tried fire lapping? Does it really work? Here’s an article I found about it.

https://www.ktgunsmith.com/firelapping.htm

[DonHowe]

In my limited experience fire lapping works. How it works and the end result seems to be much debated.
My experience, which some might not call lapping, was with a brand new Ruger Bisley .44 mag revolver. I "lubed" 50 sec bullets with JB bore paste and loaded and fired them with a medium .44 Spl load. Ok, maybe it was polishing. I do know no bullet of WW or harder alloy never loaded for me a magnum velocity.

[LAGS]

I have Fire Lapped many a Rusted Mil Surp Rifle.
The lapping worked to remove lots of the Crud in the rifling.
But it did nothing to remove any pitting.
The barrels actually showed any pitting more , but the barrels in general shot Better.

[Zingger]

I have a Ruger #1 in 7x57, one of the "new" ones. Next to no throat. Run a bullet beyond cannelure and you would see hard to close and rifling imprinted, just barely. Bought it as a "next to new" on GB, showed up and I looked down the bore. Rust.... action had never been cleaned and had rust. Got it straightened out (if you can call it that) but could never get it to group decent. Someone besides me decided it needed to be free floated and cut a great deal out of the forend. Tried light, heavy and all in-between loads. Out of desperation I ran 5 of 320 and 5 600 grit cast boolits and cleaned the heck out of it between grits. It could have been the fire lapping, or it could have been the complete de-coppering of the grooves. But now I can seat bullets "out there" and shoot pretty much whatever I want and it will go into 1-1.5 at 100 yards, where before the best/safest place to be would have been in front of the barrel! Sorry for the novel, but I feel that the fire-lapping has it's place. Best of luck!
Zingger

[contender1]

Fermin Garza wrote an excellent article on firelapping handguns,, and it should be studied.

In short,, yes,, it has helped many guns,,, but I've never heard of it hurting one.

[Bazoo]

https://gunblast.com/FerminGarza-Firelapping.htm here's the Fermin Garza article.

I'm in process of fire lapping my stainless GP100, using mostly that article as a guide. Well see how it does at cutting the constriction out, and thus reducing leading. After 36 220 grit, and 24 320 grit, slugging produces a much improved lesser amount of constriction. It also has noticeably worn the breech end of the rifling. It's not as pronounced. If it cures my problem then it's not an issue, but I'm considering using a forcing cone reamer to sharpen up the rifling ends. We'll see.

I've not fired it since the last fire lapping session, but that's next, save a good cleaning.

[Winger Ed.]

I've done a couple of pistols, and it helped put a mirror finish inside the barrels.

But I was always a little leery of using the coarse grits in mine.
5 shots with a soft cast boolit, real fine grit, and going slow enough to see it fly out the barrel did a good job for me.

[GregLaROCHE]

Could you fire lap a smooth bore muzzle loader by putting lapping compound on patches? I’m thinking of cleaning up old barrels.

[Bazoo]

You could probably just lap a smoothbore easy enough. Cleaning rod in a drill with a patch holder and a piece of cardboard covered with compound.

[GregLaROCHE]

You could probably just lap a smoothbore easy enough. Cleaning rod in a drill with a patch holder and a piece of cardboard covered with compound.

I’ve thought about doing that, but worried I might end up with uneven rings. I guess if I keep moving it back and forth like a hone, it could work.

[largom]

I have fire-lapped numerous barrels [rifles] for customers and my own over the years and all showed improvement in accuracy. In fact, my habit when I purchased a used rifle was to fire-lap the bore before anything else. Have also fire-lapped many new rifles for customers. At present I have some David Tubbs bore polish kits [fire-lapping] kits in the S&S section.
Larry

[Slugster]

It has been recommended using a piece of copper cleaning pad from the buck store wrapped around a bore brush for cleaning the bore prior to fire lapping. REAL copper cleaning pads are about 14.00 per bag. The "copper" pads at the buck store and wallyville are steel that has been copper washed to make them look like copper pads. These cheapies will rust and are magnetic. I would not use them.

[GregLaROCHE]

So when fire lapping a rifle bore, how important is it to use a copper jacked bullet?

Also how would putting a lapping paste in the lube grooves work?

[waksupi]

Could you fire lap a smooth bore muzzle loader by putting lapping compound on patches? I’m thinking of cleaning up old barrels.

Yes, use around 10 gr. powder.

"I’ve thought about doing that, but worried I might end up with uneven rings. I guess if I keep moving it back and forth like a hone, it could work."

Uneven rings? Do you mean the light bars?

"So when fire lapping a rifle bore, how important is it to use a copper jacked bullet?

Also how would putting a lapping paste in the lube grooves work?"

I've always used lead bullets. The compound is put on the bullet, and rolled on a sheet of glass to imbed the particles. The lube grooves would do nothing for you.

[303Guy]

I am wanting to fire-lap some 22's. I have found that 60gr sub-sonics are perfect for the job. Apart from not having any fine grit, I was scared to put more than polishing compound through the bores. It did seem to clean them up. 22's are small and the prospect of cleaning out the actions with compressed air is a bit daunting too.

Anyway, I have fire-lapped a few rusty 303's which cleaned out the rust and crud real good and exposed all the rust pits but supposedly also rounded the edges of the pits. My fire-lapping was very aggressive, requiring only two shots to clean out all the rust. I used machined brass fire-lapping bullets with grit grooves and a guide disc up front on a stalk. These things have to be banged through the bore quite hard or they might stick in the throat and if the pressure is sealed in it's game over. I cut small gas leakage grooves into them for safety. I probably won't use that trick again though.

One of my most accurate rifles was cleaned out this way.

https://i.postimg.cc/wMXsST08/MVC-565F.jpg (https://postimages.org/)

The front disc guides in the bore and the next three seat in the throat taper. The idea being that with this degree of aggressiveness, the projectile should at least enter and travel the bore straight.

The two rear grooves hold the compound and seat inside the neck so not grit gets into the action or chamber. This could be done with lead boolits too but I don't know effective that would bee. The brass doesn't wear away like lead would.

https://i.postimg.cc/Y05h9fdJ/TWO-GROOVE_BORE_003.jpg (https://postimages.org/)

After fire-lapping that accurate rifle, I cut the muzzle back for good measure then split it to have a look. That rifle doesn't even copper foul - ever.

[GregLaROCHE]

Your brass lapping bullet is impressive. I’m thinking about cleaning up older guns too. I can see how the harder brass would work faster than lead. I think that’s why copper jacketed bullets have been recommended. I have a small lathe, but before I get into marching brass, I think I will try casting some pure linotype boolits to use.