Author Topic: Fire (pressure) lapping barrels (Read 540 times)

Cheyenne Ranger · « **on:** March 03, 2004, 06:59:44 AM »

Got a fire lapping kit coming (had $$ and nothing to spend it on :grin: ).

When I was slugging my Rugerette 32 barrels (didn't know if they were .311 or .313--turns out .311 works fine) the slug came out all rough. I was truly amazed at how rough it was!

So decided to try fire lapping (at CAS ranges this is not necessary). I don't know how to do this so it would be something new to learn.

The short version is you fire jacketed or very hard cast bullets through the gun. They are impregnated with finer and finer grit. Think it goes from 220, 400, 800? and 1200. Fire 6, clean, slug to check roughness and then go to next finer grit. I have pure Pb (lead) plus tin an antimony so I can cast my own so I can do this on the cheap ($67). The amount of grit should do about 10-12 revolvers, give or take. I've got 6 revolvers plus two lever actions so I should be set ('course I've said those words before and have been badly mistaken :eek: )

Will keep you posted on process.

CR

HWooldridge · « **Reply #1 on:** March 03, 2004, 09:30:07 AM »

Wish I had $$ and nothing to spend it on...

Anyway, I did this on an 1860 Uberti and used grease based 400 grit Clover Compound. I loaded a normal charge and greased the top of the ball like you would do with tallow to prevent chain fires. I fired four full cylinders separated by a dry barrel wipe between each reload. Before lapping, there were some chatter marks near the muzzle. After cleaning, the barrel shown like a mirror. Although it still shoots high (like most every other cap and ball), it yields one-inch groups or better at 25 yds if I hold it well. It has killed a few coons in the last year or so and rolls them right on the arse with a round ball.

I don't think you need to use hard cast or jacketed. Just load any lead bullet and cover it with compound. In addition, the lightest load that will make the bullet leave the barrel is sufficient to lap.

Cheyenne Ranger · « **Reply #2 on:** March 03, 2004, 12:32:37 PM »

Thanks HW,

The guy selling this said that the harder bullets will not deform as much and allow the grit to do its "thing." He agreed it would work with soft ones but would probably take longer.

And too, low powder--just let it get out of the barrel + a bit. Nothing high power

ÇR

Will52100 · « **Reply #3 on:** March 03, 2004, 08:17:51 PM »

Sounds like something I could do to help my cap n' balls, but where do you get grease based 400 grit Clover Compound?

Thanks,

Will

ButlerFord45 · « **Reply #4 on:** March 03, 2004, 11:52:55 PM »

It isn't something I have done, but here are some folks with some definately strong opinions of what should or should not be done and how to or not to do it.

http://www.shootersforum.com/showthread.htm?t=9600

MOGorilla · « **Reply #5 on:** March 04, 2004, 02:01:25 AM »

Is this something that could be taken care of with bore paste? I had always heard on new guns, you needed to shoot them ~100 times to season the rifling. I came here and read Gatofeo's posts in Cap and Ball and he mentioned using J&B bore compound on new guns and periodically afterwards. I tried it out on my new 51 navy and man were the results pleasing. I was used to the first 50 or so shots out of a new gun being all over-these were dead on from the gitgo. Anyway, it is a fine grit-probably in the 400+ range, you apply with a patch and rod like you were cleaning, then follow with a thorough cleaning. Worked great for my henry too.

Cheyenne Ranger · « **Reply #6 on:** March 04, 2004, 03:25:21 AM »

Probably several ways to do this. Remember old timers saying that if you shoot 50,000 rounds you will have a nice, smooth barrel :grin:

Figure this way give me a reason to shot some more.

ÇR

HWooldridge · « **Reply #7 on:** March 04, 2004, 03:35:12 AM »

Will,

Clover Compound is valve grinding paste, which can be had at NAPA or any of the industrial supply companies. Doesn't have to be Clover brand, that's just what I had on hand.

As long as you don't get a lump of abrasive in the barrel and cause an obstruction, I think fire lapping is safer and faster than using a bore brush - plus it's more fun...H

Cheyenne Ranger · « **Reply #8 on:** March 04, 2004, 04:43:04 AM »

To the question about extra $$, I was "strongly" looking at a Henry 1860 over on the SASS wire and while I was waffling the owner sold it. Not a problem as $$ in the hand always tops questions.

ÇR

Will52100 · « **Reply #9 on:** March 04, 2004, 08:46:20 PM »

Thanks HWooldridge, that's what I figured it was but wasn't sure. I'll give it a try on one of 51' navies, the bore is pretty rough.