Author Topic: fire lapping (Read 929 times)

Steel killer · « **on:** January 23, 2004, 12:56:31 PM »

Has any body tried fire lapping, I have had good results with rim fire,
1200 fps and a soft lead bullet and 500 grit would smooth things out, uniform the bore dia.

Thanks steel killer

RandyWakeman · « **Reply #1 on:** January 23, 2004, 01:12:51 PM »

http://www.graybeardoutdoors.com/phpbb2/viewtopic.php?t=21801

Veral Smith is probably "the guy" that can help the most. I've viewed it more as an act of desperation than anything else, and twenty shots of Powerbelts (or other bore-sized conicals) seem to smooth out a new barrel a bit before changing its diet to plastic.

Oldsnow · « **Reply #2 on:** January 23, 2004, 05:04:41 PM »

I have fire lapped my Omega and Encoreand it helped make loading easer and made group size smaller.

Jayhawk Dan · « **Reply #3 on:** January 25, 2004, 01:15:52 PM »

Where to I get some information about "fire lapping" muzzle loader barrels? I read an article in "Gun Tests" magazine that mentioned fire lapping and using both J-B Compound and "150 grit valve grinding compound." However, the details were lacking. Where can I go to get more information about this?
Thanks in advance for your help!

Jayhawk Dan

RandyWakeman · « **Reply #4 on:** January 25, 2004, 01:40:27 PM »

http://www.findarticles.com/cf_dls/m0BQY/11_46/65574862/p1/article.jhtml

is a short description of J-B Bore paste. I got mine from Brownells-- some use the 200 or 300 stroke method as the "J-B" treatment. I'd hesitate to call it "barrel lapping," as mild of an abrasive as it is.

Veral Smith, mentioned above, sells lapping kits.

Another source is here: http://www.neconos.com/details2.htm .

Jayhawk Dan · « **Reply #5 on:** January 25, 2004, 02:55:58 PM »

Thank you, Randy, for this helpful information!!

Jayhawk Dan

RandyWakeman · « **Reply #6 on:** January 25, 2004, 05:38:54 PM »

Don't know how helpful-- the J-B Bore way is a fairly safe, non-invasive thing to try. I've never heard of any problems going that route.

As for the rest, I have no experience with it. I do know that some have said they have had luck mixing fine grit lapping compound with bore butter, and applying it to knurled conicals. A few shots, clean it all up, inspect your barrel, then test it out. But, no specifics.

big6x6 · « **Reply #7 on:** January 26, 2004, 03:24:30 AM »

I may be missing something but I have NEVER lapped any bore in any way. I suppose a little JB here and there wouldn't hurt anything and might help to remove any plastic, lead, or copper residue. My experience is either a gun shoots or it doesn't. Bedding or floating the barrel may help but I've never turned a gun that just won't group into a 1 inch gun...

woodseye · « **Reply #8 on:** January 26, 2004, 10:24:17 AM »

I think the theory is Chuck, that the new bore has sharp edges especially in button rifled barrels and they tend to cut and reduce the seal of the sabot to the bore. You hear it makes the bullets seat easier and brings velocity up slightly.........the comments about accuracy would require a through evaluation both before and after lapping and this seems to be seldom done. The 200-300 stroke method with JB bore paste would really be more of a hard cleaning to remove barrel grease and any chips from a new barrel than a real lapping job as preformed by a smith with much more abrasive compounds or fire lapping with grit embedded bullets.

The fact that the Savages are coming with an accuracy target tells me that the factory is shooting them without any lapping and apparently doesn't think its too big of a deterrant to accuracy. Randy seems to have good success with accuracy in his test guns without the process also. Will probably do the JB paste thing to remove any burrs or sharp edges from rifling and let it fly as I agree with you........it won't make a 1 3/4-2" gun into a sub MOA in my opinion.

woods

Steel killer · « **Reply #9 on:** January 27, 2004, 02:24:15 PM »

Thanks for the replys,I have hand lapped a TC Renegde many years ago.
That involed makeing a stiff rod on a bearing , then casting lead plugs
around the rod while in place in the barrel. Then you push the 3'' plug half way out of the bore and coating with grit. Run it back and forth until the bore is slick and uniform. Recasting lapps as needed. {Lots of work}
Fire lapping involes rubbing dry grit (I use 320-500 for 22 rimfires)
onto the bullet and fireing said round. (Clean every 2 or 3 rounds to avoid sticking a round in the barrel.Make sure every round exits the bore before firing next round). My plan is to rub maxie ball with dry grit and fire useing one pellet of 777 bush and dry patch between shots. Be careful not to enbed the grit onto the rod. I am giving some thought to useing power belts instead of maxie balls. any thoughts on useing the power betls. Will the power belts upset and engrave the groves and lands???

steel killer

Jayhawk Dan · « **Reply #10 on:** January 27, 2004, 03:04:14 PM »

I really appreciate all the feedback on my post asking for more information about "fire lapping." Thanks very much to everyone.

My understanding of this "lapping", from what little I do understand, is that it has very little to do with improving accuracy. It apparently does help reduce residue build-up on rough edges in button-rifled barrels. At least that is the context of the articles and posts I've read.

Again, thanks to all!!

Jayhawk Dan

RandyWakeman · « **Reply #11 on:** January 27, 2004, 04:19:18 PM »

It's comments like this from Lilja barrels that have dissuaded me from being a "lapping proponent":

Quote

Q. What is your opinion of the BlackStar process and Fire Lapping?

A. We feel that any internal finish treatment of our barrels, performed by another source, will only serve to degrade the extremely smooth and uniform finish we achieve through hand lapping. Over the years we have developed a proprietary lapping system that allows us to create a superior internal finish. We have found through our testing what is the optimum lapping material and grit. With the finish our barrels are shipped with (especially the stainless steel barrels), bullet jacket fouling is almost nonexistent, and accuracy is at its peak.

One of the reasons we believe that fouling is minimal has to do with the direction of the surface finish in relation to the rifling. When a barrel is lapped, the resulting surface lies parallel to the rifling. The bullet does not have to rotate "against the grain" as it would have to with an unlapped barrel or with a barrel treated in another manner.

Another factor in surface finish has to do with its smoothness. While it is very desirable to have a finish running parallel to the rifling, the finish can be too smooth. In our extensive testing we found that a lapped barrel could be made too smooth and that these super smooth barrels would foul more than our conventionally lapped barrels. We have drawn an analogy between these "too smooth" barrels to racing slicks on race cars. These tires have no tread so they can get better traction (or more friction) on the asphalt or concrete surface. It seems as though a similar situation results between a bullet and barrel if the finish is too smooth. But in this case, the result is increased fouling, not increased performance.

Many of the comments made about the BlackStar process also apply to the Fire Lapping procedure. But the big problem with Fire Lapping in our opinion is the rapid deterioration of the throat in the barrel. We know of barrels that have had the throat advanced very rapidly to the point that the chamber had to be set back.

So, it is for these reasons that we do not endorse the BlackStar process nor suggest that customers have their Lilja barrels treated by this firm. The same is true of the Fire Lapping system. If we thought that we could improve the internal finish of our barrels we would do so in-house, not rely on an outside source to do so. Further, if a customer has a complaint about a barrel and it is shown that our original internal finish has been tampered with, any warranty claim is void.

Doc White and others have observed that ML barrels tend to improve during the first 200 shots all on their own, with bore-sized projectiles.

The J-B Bore paste treatment seems reasonable, just shooting 20 - 30 Powerbelts seems to help before going off to sabot land-- but, I've never heard of a "6 inch gun" miraculously becoming a 1/2 MOA gun with home-brewed lapping. Maybe it has happened, but that would be a new one for me.