fire lap - powder??

[rp85]

hello;

going to fire lap an mil. surp. rifle barrel in 308win.

can anyone suggest a load to use to fire lap the barrel. powders on hand, red dot, green dot, and unique. plan on using a 180 grain lead bullet. thanks for any input.

rp

[excess650]

You only need enough fast burning powder to ensure that the lapping projectile exits. 3gr of Red Dot should suffice.

[bigjake]

Fire lap ?

could someone fill this guy in on what fire lapping is?

thanks

[geargnasher]

You only need enough fast burning powder to ensure that the lapping projectile exits. 3gr of Red Dot should suffice.

+1. Three grains of any fast powder (no matter) would be my recommendation too, but I'd add a half-grain Dacron fluffed up inside the case to keep the powder against the primer and also act as a "mop" behind the boolit, it really keeps the abrasive evened-out in the barrel during the process and helps the cleaning process. If you fill your grooves with Clover Compound as well as embedding the driving bands properly the Dacron really helps seal the boolit in the barrel without blowing the compound out the muzzle ahead of the boolit, since your firelapping loads won't develop enough pressure to make the lap seal well.

Gear

[geargnasher]

Fire lap ?

could someone fill this guy in on what fire lapping is?

thanks

Lazy man's alternative to hand-lapping.

Firelapping is a process of abrading or polishing a gunbarrel by firing extremely low-velocity lead alloy "laps" through it like normal boolits. The laps are usually just boolits that have been carefully embedded with a cutting compound, usually silicon carbide, and sometimes with the lube grooves filled with the abrasive and grease mix. The purpose is to smooth the bore to a uniform size, polish, remove restrictions, unify the land width, and if done properly, add a measure of taper from throat to muzzle.

The total number of shots required, abrasive grade, frequency of cleaning between shot strings, etc. varies greatly with the gun in question and the condition of the bore.

Gear

[bigjake]

Lazy man's alternative to hand-lapping.

Firelapping is a process of abrading or polishing a gunbarrel by firing extremely low-velocity lead alloy "laps" through it like normal boolits. The laps are usually just boolits that have been carefully embedded with a cutting compound, usually silicon carbide, and sometimes with the lube grooves filled with the abrasive and grease mix. The purpose is to smooth the bore to a uniform size, polish, remove restrictions, unify the land width, and if done properly, add a measure of taper from throat to muzzle.

The total number of shots required, abrasive grade, frequency of cleaning between shot strings, etc. varies greatly with the gun in question and the condition of the bore.

Gear

Thanks gear.

Looks like I wont be fire lapping anytime soon :redneck:

[runfiverun]

paper patched will do it too, and a bit of grit will speed up the process.
or some p/p [with high titanium nitride paper] at the end will add a smoothness you can be proud of.
i just use lead projectiles with high antimonial alloys ,that will usually smooth out a bbl pretty good. but it only smoothes the bbl in one direction.

[MtGun44]

Boolit must exit barrel. All other requirements are optional.

Bill

[DukeInFlorida]

With the help of one of the members here, Bob_J (a previous reloading class student, and now a wonderful reloader and caster), I was able to fire lap an off-the-shelf Remington Model 700 in 30-06, and went from 1" groups at 100 yards (before lapping) to 4" groups at 600 yards (after lapping)!!!! Most of the variation at 600 yards is ME!

For an off-the-shelf gun, it shoots almost as well now as some "F Class" guns.....

Fire lapping is a wonderful process in SOME guns.....

It can make a good barrel wonderful.

It won't make a worn out barrel new again.

[303Guy]

It won't make a worn out barrel new again.Ummm.... well maybe it can. We are talking cast boolits remember. That means we can custom size the boolit. Some barrel wear might be in the muzzle area. That needs to be chopped off and recrowned. Even a rust damaged bore can be made to shoot.

[geargnasher]

Ummm.... well maybe it can. We are talking cast boolits remember. That means we can custom size the boolit. Some barrel were might be in the muzzle area. That needs to be chopped off and recrowned. Even a rust damaged bore can be made to shoot.

+1. One of my favorite shooters has a gawd-awful pitted-up bore, but it showed me that as long as 75% of the original land and groove structure remains, the caster and reloader has the means to make it quite shootable.

Gear

[btroj]

Fire lapping a pitted barrel sure won't hurt anything. I have had good results with it in removing thread choke. I view fire lapping as a process that is needed in some guns. Let the gun tell you what it needs. It is going to make a barrel new? Nope. But it sure beats having a rusted out barrel that won't shoot or rebarreling a milsurp. It is a tool. No more, no less.
As for a good powder, I like trail boss.

[calkar]

Amen on the tool. I just bought a rusty bored, bubbaed, no numbers matching mosin (cheap) because I wanted to cut one down to a 18.5" barreled carbine, utility rifle, that I dont have to worry about scratching or bumping. I will have to fire lap, because while scrubbing with abrasive on a patch over a bronze brush, I noticed I was grinding away what was left of the lands and not effecting the grooves equally.