Can some one help me with fire lapping?

[walker77]

I dont know what forum this would go in, so im putting it in this one since it gets a lot of traffic. I bought a fire lapping kit from beartooth bullets for my S&W 629 44 mag. Ive put about 30 rounds through it so far, most of them got stuck in the barrel and i had to knock the bullet back out with a dowel rod. Ive cleaned the barrel a littled and looked down it with a light, and its already like looking at a mirror in there. But there is one area down by where the threads would be for the barrel where i can see small grooves or scratches running a short ways along the valleys in the rifling. At first i thought it was leading, but that isnt possible. Its defiantly in the rifling. Is this typical? Or is it something to be concerned about? I know there was a constriction around in that area. I havent been able to get any more sinkers to test it out again. But i was shooting jacketed bullets, i wonder if that is where the scratches came from. So i guess my question is, should i keep going these scratches or grooves are gone? Thanks guys

[stubshaft]

J words will not scratch the barrel. What you are seeing is probably the boolits removing some of the constriction in the barrel. However, this would mean that you are using a very aggressive lapping compound.

[walker77]

I dont remember the grit, its what ever they gave me in the kit. Will it be a problem???

[walker77]

anyone else?

[btroj]

I doubt you have hurt anything. Go shoot it and see what the gun says.

[stubshaft]

I doubt you have hurt anything. Go shoot it and see what the gun says.

+1 - I would slug the area and if you are close to your final or desired dimensions switch to a less aggressive compound.

[tek4260]

And up the charge so you aren't sticking your firelap boolits! :)

[Crusty Deary Ol'Coot]

Yes, up the powder charge, as if the boolit is not passing all!!!!!!!!!! the way through the bore, you are getting the job done!

Veral Smith, at LBT used to sell "push through" slugs for checking the bore before. during and after firelapping.

Keep em coming!

Crusty Deary Ol'Coot

[walker77]

Yeah, i know it needs to be upped a little. I dont want to go too high because im shooting it in my garage, and i live in the city. My little 3 yr old girl already came running up stairs and told my wife that daddy is shooting guns in the house. My wife thinks you people have corrupted me....

Right now, i am using 1.8 grains of unique and shooting it into a bucket of water. I get different results every time. I would say one time out of 12 the bullet actually comes all the way out. I think the powder is getting wet when it touches the lapping compound. By the way, the lapping compound is 320 grit. I can already see flat spots starting to show up in the valleys near the forcing cone. So i can see where the high spot is, i guess i just have a little ways to go

[curator]

If you are shooting straight down you might want to add a small tuft of dacron or half sheet of toilet tissue to hold the powder back against the primer. 1.8 grain of Unique should do it but 2.0 may be required to push the bullet through the barrel each time. Another technique that works with small charges in fire-lapping is to use unsized once-fired cases is to push bullets as deeply as they will go inside the case. This reduces the case volume and makes the small charge burn better to give higher velocity. They usually stop near the base where the case walls thicken. Grittiness will hold them there with friction. I have done this in my garage but use a 7 gallon bucket filled with sand to catch the bullets. Water gets pretty messy unless you have some kind of diaphram over the surface. Get some .440 pure lead round balls from someone who sells muzzle loading supplies to use as push through slugs. They will be easy to start and will show tight spots. It usually takes 50+ lap-shots to polish out a .001 thread choke. More shots for tighter constriction. One Ruger I had needed 200+ lap rounds to remove a .003 tight spot.

[walker77]

I tried packing a cotton ball down in there, but that didnt seem to help. I would think cramming the bullet all the way down in the brass would create a dangerous pressure levels.

[tek4260]

Ride to the edge of town and shoot? I can see all sorts of bad things happening shooting in the garage into water. I used the lee dipper that came with 45 Colt dies and Trailboss to do mine. 1.7cc comes to mind.

May be a good excuse to build a rubber mulch boolit trap to shoot in your garage!

[EDK]

I tried packing a cotton ball down in there, but that didnt seem to help. I would think cramming the bullet all the way down in the brass would create a dangerous pressure levels.


First, go read 2 Dog's article on firelapping over at gunblast. Or send him a PM here. He is a well of information and can answer your questions AFTER you read the article. Subsonic had a recent thread also...mentioned shooting in the basement?

I'm doing my own variation. I dab 320 grit CLOVER COMPOUND in the forcing cones before I take a set of guns downhill to my target range. (Yeah, I know I'm lucky to be able to do that...it's 20 miles to Saint Louie and the Arch.) My current load is the MIHEC hollow base wadcutter sized to .433 and 6.5 of HERCO, using carnuba red. I take a MAG-LITE with me and check the barrels after 24 rounds or more. If I see lead, I shoot 6 rounds of RANCH DOG TLC 432 265, gas checked and lubed with LLA or some similar concoction, sized to .433, with 7.5 of HERCO.

:Fire::cbpour::redneck:

PS Remember your little girl will be a woman some day...then she will join the ranks of those who barely tolerate male antics! It sounds like she is headed that way already. I had two daughters...ask me how I know these things!

[walker77]

EDK, do you have a link to that article?

[geargnasher]

First things first: What were your "before" measurements of cylinder throats, full-groove, and groove at threads? Why are you lapping it? Have you proven through measurement and analysis that you have a dimensional issue that is causing problems with leading or such that indicated firelapping as the solution? Have the shots you've fired so far changed any of the dimensions, and if so, how much?

Second, PLEASE, before you pull the trigger, shoot where it's safe (make a better trap or find a more remote place to shoot), and use enough powder to expell the boolit or you might create more problems than you solve.

Gear

[303Guy]

I don't want to go too high because in shooting it in my garage, and i live in the city.I live in a suburb and do my testing in my shed in the front! My neighbors are real close. I fire full house 303 Brit rounds and no-one knows!:Fire: The trick is my 'Test Tube'.:roll:

http://s388.photobucket.com/albums/oo327/303Guy/?action=view&current=MVC-558F_edited-1.jpg

[1bluehorse]

The grit with the Beartooth kit is fine. And yes, use once fired UNSIZED brass. Using the light loads for firelapping you can and should seat the bullet flush like a wadcutter. Clean after each cyl full fired. Blued guns will lapp much quicker than stainless. I ran over 100 thru a stainless Ruger before it cleaned up. Blued usually around 30 to 40. You should be using a target so you can see when the groups tighten up. Thats when you quit...Read the instructions that came with your kit again..

[EDK]

EDK, do you have a link to that article?

Do a search here on firelapping and be amazed. I just found almost 300 threads. The article is at gunblast.com and the author is Fermin Garza. (I'm computer illiterate and don't know how to put a link in the reply.)

[crabo]

I firelap in the garage and shoot into phone books. I use about 2 grains of Bullseye and the boolits never exit the first 2" phone book. (of course I have about 6 of them stacked up in a cardboard box.)

[walker77]

I live in a suburb and do my testing in my shed in the front! My neighbors are real close. I fire full house 303 Brit rounds and no-one knows!:Fire: The trick is my 'Test Tube'.:roll:

http://s388.photobucket.com/albums/oo327/303Guy/?action=view&current=MVC-558F_edited-1.jpg

With firelapping, you just want the bullet to exit the barrel, nothing more. Or at least thats what the instructions said.

[walker77]

I firelap in the garage and shoot into phone books. I use about 2 grains of Bullseye and the boolits never exit the first 2" phone book. (of course I have about 6 of them stacked up in a cardboard box.)


How much do you think i should use of unique? I have that and trail boss and H110.

I can defiantly tell there was a constriction around the threads. I can see a small flat start to develop in that area in the valleys of the rifling.

[jandbn]

Walker77,

I used Veral Smith's lap kit on my SS 45 Bisley. Boolits were 280 grain WFN air cooled wheel weight (BHN around 12) in unsized cases with Trail Boss. I seated the boolits most of the way and then when the cartridge was placed in the cylinder, I seated the boolit the rest of the way in the case with finger pressure on the case head. The boolits were fired with muzzle pointing straight down.

For a container to catch the lapping boolits, I stuffed a catch rag (old t-shirt) into an 8-inch-tall 3-inch-diameter paper sided can with a metal bottom and fired into the rag. The end of the muzzle was poked an inch into the wadded up rag. This was my third time at lapping the Bisley (I measure often). The first lapping shot this go around was 3.5 grains of TB and it dented the bottom of the can so I dropped the charge weight to 3.0 grains and had the next two boolits stick in the bore. I went about half way between and used 3.3 grains with all remaining lapping shots and did not have any more stuck boolits (or dented can). YMMV! I removed each lap boolit from the rag before firing the next into the rag.

Noise was a factor, but I wasn't worried about the noise; it was no worse than the fireworks going off in the rest of the neighborhood a couple days after the 4th of July. I'm not sure how you would safely reduce noise if that is a concern.

[MtGun44]

Use a faster powder like Bullseye, Clays, Red Dot or something like that. About 1.5-2 gr should
do it and will have a shorter pressure pulse than Unique and probably will be quieter while
driving the boolit better. Make sure you know accurately where you started. You are
measuring with a .0001" rated micrometer, not a caliper, I hope!

Make up a carpet pad from scrap and put the muzzle right into the pad when you fire to
quiet it down. Might start the carpet on fire, so have some water handy - guess you can
drop it into the bucket.

Bill