Firelapping

Stu Farish

Stu Farish

Director / Webmaster
Staff member
The question of firelapping has come up recently.

Beartooth Bullets sells lapping components. Currently their website advises a 6 month wait on bullet orders, but that fire lapping bullets and related supplies are in stock. Go to:
www.beartoothbullets.com

If you shoot a Marlin lever action rifle (any caliber, I think it's relevant to all) you should read the 2 articles he did on the 444 Marlin. Go to:
http://search.atomz.com/search/?sp-q=.444+Marlin-&sp-k=&sp-a=sp051ea000

There are 2 links on that page to read. A real eye opener on what these rifles are capable of
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Now, a company called NECO also produces fire lapping kits and supplies. I don't have a URL for them.

CAVEAT: Firelapping is a potentially destructive process. You have to handload to do it, mostly, though I think NECO used to sell loaded ammo kits for it. You are sending a bullet coated with an abrasive lapping compound down your bore. This is going to remove steel. This could eat the throat out pretty good. I've never yet firelapped one of my rifles. I am considering doing it to a .444 P Ouutfitter, due to the Beartooth Bullets experience with Marlin barrels, but I'm going to slug the bore and see if it has the same constrictions that he's been finding before I decide anything.



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"When They turn the pages of history,
When these days have passed long ago.

Will they read about us in sorrow,
for the seeds that we let grow?" - RUSH, "A Farewell To Kings"
 
I did 2 rifles with the NECO kit. Lots of work. Prepare bullets with each grade (there are 4 different grits),starting with the coarsest grade, load, fire, slug barrel, feeling for tight spots. Really gets subjective, as you judge how much is enough.

Repeat above steps a number of times. Be REALLY careful with the coursest grits. By the time you get to the finest (it is a "polish" operation) you can just shoot from 10 to 30 of them, without slugging.

I don't know that it improved accuracy, but CLEANING is many times easier. Helps a lot when you are shooting PDs.

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Critr

fea6c171.jpg.orig.jpg

www.SaguaroSafaris.com
 
I firelapped a new .45/70 Browning BPCR with a components obtained from LBT in Idaho. I understand that LBT is currently out of business; hopefully they will get restarted soon.

This was an interesting project to say the least. Before I started I ran some "push through" bore slugs through the barrel. It felt like I was pushing the bore slugs through a plowed field with rocks in it. Not a good recommendation for a brand new rifle that cost a bundle. After the bore lapping was complete (about 30 rounds in this case), the bore slugs could be pushed smoothly through the 30" barrel.

Without rechecking all my notes the process opened up the bore diameter about 0.0009"; however, the big improvement was no tight spots in the barrel, and the barrel was as smooth as glass. The barrel now measures 0.4588" at the muzzle and 0.459 at the breech; I shoot a 409 gr. LBT long flat nose bullet sized at 0.460". I don't shoot many groups on paper; most of my shooting is done for effect. However, the best group I have shot on paper so far is 3 shots in 5/8" c/c at 100 m. (Fed 210, 40 gr. H4198, WW brass) with a post front sight and Creedmore style peep rear sight.

The pigs at 300 m. don't fall off the rail; they jump off the rail. A real killer on deer, too. This is a really fun rifle; I shoot it more for general shooting than any other rifle I own in which I shoot smokeless powder.

From what I can see this process could probably improve the quality of many barrels especially on newly manufactured rifles. If a rifle suffers from lack of precision, some fire lap rounds can potentially improve the situation. This is much cheaper than a new barrel or a new rifle that may have the same problems as a currently owned rifle. The process definitely removes tight spots (ultimately this is lack of straightness) and corrects a bell mouthed muzzle. A bell mouth muzzle is apparently quite common and doesn't do anything good for precision shooting.
 
Thanks for the link.

------------------
"When They turn the pages of history,
When these days have passed long ago.

Will they read about us in sorrow,
for the seeds that we let grow?" - RUSH, "A Farewell To Kings"
 
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