Once more into the fire.....lapping

[1bluehorse]

So I traded this guy out of an old 3 screw SBH 7 1/2 incher. He told me he never could get it to shoot well. Well that didn't really surprise me, I know a lot of guys that can't shoot a 44mag very well. Cleaned it up real nice, (it was leaded up pretty good) loaded some of my 260gr. lead boolits sized .430 over some 2400 and went to shootin....didn't do to well, managed to hit the target every time (8 1/2x11) from 25 yds but it covered the WHOLE thing..had some 200grainers also sized .430 with 8.5 grs of 231 so thought I'd try those. VEEERRRYYY good, shot the center out...hmmmmm, says I, tried the 260s again with 231, uh-huh..more of the 200s with some HS6, yep, 260's nope...quite a bit of leading too I might add. Cleaned it up again and went to measuring, throats are .432 (no surprise there) could start a .416 pin gauge in the bore but only went about an inch...o.k. we have some bore constriction. I just happen to have a lapping kit, so cast a few (30) boolits and proceeded to make up some lapping rounds using the 200gr Lee RNFP over 3.5gr of 231. (I load them nose down, flush with the case) Shot 24 (shoot six, scrub bore, six more ) cleaned er' up, the .416 gauge slips all the way through, .417 won't start so I'm good to go. Did the 100 strokes with the bore mop covered with lapping compound, clean again (real easy this time)....Same 260gr. .430 boolits (RCBS mold) over 16.5 gr 2400, 25yards, 1 1/2in group....no leading...yep I'm pleased...I've done quite a few Ruger 45 colts, but they were all fairly new guns, I was surprised that a gun this old and well used (and boy it is) would still have these issues...obviously I need to shoot this a lot more to confirm all this, but I'm pretty sure the results will be the same....

[Catshooter]

I agree, firelapping is an excellent tool for the tool box. It can give some startlingly good results.


Cat

[Lefty SRH]

I have 3 guns that could possibly benefit from fire lapping. I'd like to ry it but I need some details.
Alloy used, I assume its pure lead or atleast tape weights is used?
What brand and grit lapping compound?
How do you impregnate the boolit with the compound?
How do you prep the cases? I've read you don't size the cases AND you thorw away the cases that are used.

Give me the skinny please.

[2 dogs]

1bluehorse, try a .432" diameter bullet, It may even get better!

[2 dogs]

Here:

Alloy used, I assume its pure lead or atleast tape weights is used? 12 BHN
What brand and grit lapping compound? CLOVER
How do you impregnate the boolit with the compound? BY ROLLING
How do you prep the cases? I've read you don't size the cases AND you thorw away the cases that are used. CHECK FIRED CASES FOR FIT IN YOUR CYLINDER

THE SKINNY:

http://www.gunblast.com/FerminGarza-Firelapping.htm

[1bluehorse]

I have 3 guns that could possibly benefit from fire lapping. I'd like to ry it but I need some details.
Alloy used, I assume its pure lead or atleast tape weights is used?
What brand and grit lapping compound?
How do you impregnate the boolit with the compound?
How do you prep the cases? I've read you don't size the cases AND you thorw away the cases that are used.

Give me the skinny please.

First I'll tell you the lapping kit I"ve used on all the revolvers (and one rifle) is from Marshall Stanton (Beartooth Bullets). Go to that web site and look up firelapping. Better info there than I can relate here.. There's also a good writeup in the tech notes on lapping a Ruger in 36 rounds. This is the method I use. The compound Marshall uses is (I think) the best. The first time you firelapp is kinda scary, you think you're for sure gonna screw up your gun, but believe me if you follow the instructions it's quite easy. I haven't done all that many, around 15, and haven't ruined one yet ...in fact all have had some improvement in accuracy (some pretty dramatic) and leading has been pretty much eliminated..I'm a believer..

I'll add that the "kit" from Beartooth Bullets has enough lapping compound to do several guns, and I cast my own bullets, using a RNFP, keeping them at the 10 to 12 BHN. I load mine nose down and flush with the case. I got that little tidbit from another article and has worked well...

[oldfart1956]

Just out of curiousity have any of you that have firelapped ever measured before/after on the cylinder throats? Meaning that area just before the boolit exits the chamber and enters the forcing cone/barrel throat. The reason I'm askin' is I have an old model Ruger Blackhawk in .357 that has obvious thread choke from the forcing cone to about 1 1/2 or 2in. up the barrel. But the cylinder throats are perfect for my boolits and don't wish to enlarge them. Many thanks in advance. Audie...the Oldfart..

[Lefty SRH]

I've been told and have read that it does not affect the throats. The cylinder chambers only see 1/6th of what the barrel sees.

[44man]

I have worried about enlarging throats too. I take the right BHN boolits and lapping loads without rolling them, take a "Q" tip and apply lapping compound into the cone and start of rifling.
The best thing is you do not have to clean the cylinder all the time. You need to remove it all the time to apply compound. Seems to work.

[uscra112]

Ditto here. Was scared of hurting the throats when I started firelapping my stainless 681 Smith. Even pin-gaged all the throats to find a small one to use. Bottom line, it did nothing to the throats, but it made a horrific leader-up into a benign if not super-accurate boolit shooter. I can't explain why. No longer care. I'd do it again in a heartbeat.

[cbrick]

went to measuring, throats are .432 (no surprise there) could start a .416 pin gauge in the bore but only went about an inch...o.k. we have some bore constriction.

I'm confused. A pin gauge to measure the bore? You would only be measuring the height of the rifling when what you would need to know is the depth of the grooves.

Please enlighten me.

Rick

[uscra112]

True that it is better to plot groove diameter too, but if the bore is constricted, there's a good chance the grooves are also.

[Greg B.]

Another good source for fire lapping material is Veral Smith of Lead Bullet Technology. He sells a fire lapping kit and by digging around on his web site you can get the details.

[1bluehorse]

I'm confused. A pin gauge to measure the bore? You would only be measuring the height of the rifling when what you would need to know is the depth of the grooves.

Please enlighten me.

Rick

I was looking for constrictions in the bore...barrel slugged .428.5 using a mic...that was before firelapping..have not checked it since..

[Iron Mike Golf]

I firelapped my Redhawk a couple years ago. It's stainless and took a lot more rounds than what people report needing for a blued gun. No change to cylinder throats (.433). I used the beartooth kit.

I also checked progress using pin gauges. I had two constrictions: under the front sight and under the frame threads. Also had chatter marks on the lands near the muzzle. When I finished, a .416 had slight drag under the front sight and then fell free to the forcing cone. I got some 600 grit Wheeler compound and shot one cylinder of those and one cylinder with boolits "lubed" with Flitz.

No leading and shoots cast and jacketed great.