barrel lapping

[gotcha]

Has anyone had first hand experience lapping barrels w/ soft lead slug ? Friend & I are planning on doing this & looking for tips from those of you that have actual experience. Thanks for all replies, Dale

[gotcha]

C'mon guys ! No one w/ any experience bore lapping. Really ???

[Apache]

I do firelapping. A little different than most people do though. It is MUCH easier and very effective.

If this is an already chambered/crowned or otherwise finished barrel and you lap the way it sounds like you're wanting to do, you stand a VERY good chance of ruining a barrel.

But, try it if you want to. YMMV.

[Eric in NC]

Yes - lead lapping a bore is usually done before the barrel is chambered and trimmed to length. You will almost always end up damaging the throat and muzzle end of a finished barrel doing hand lapping.

Some folks report good results but if you want a hand lapped barrel better to order one or get a blank and lap it then cut an inch or two off each end before chambering and crowning.

[Hammer]

.

If memory serves me right...

The barrel makers I have visited tell me that handlapping the barrel is the highest skilled job in their shops.

Know one has to handlap their first barrel before they get to their thousandth.

My first handlapped barrel will be a throw-away barrel -- not one for precision work.

But I have put it off for a long time -- might wait a while longer.

.

[gotcha]

Thanks for the input guys ! You're all making good sense. Hadn't considered the possible damage to crown & throat. Crown could be re-cut, leade could be re-cut but throat diameter change couldn't be repaired unless the chamber end was shortened & rechambered....... I now remember WHY the muzzle end is always shortened before crowning a hand lapped barrel or any barrel for that matter............................APACHE what kind of success have you had w/ fire lapping with a BBL that was a "copper mine" ???? Could I roll bullets in 600 grit lapping compound then fire one at a time & check for improvement? Thanks, Dale

[Apache]

The only type of fire lapping I have ever done is to firelap then rechamber. Firelapping will erode the throat and leade of the existing chamber....but that was the goal from the beginning. The barrel was bought in the original chambering with firelapping then rechambering in mind.

For instance.....I would firelap a 223 and then would rechamber to a 22-250 Imp or a Swift. A 221 Fireball rechambered to a 223. That way I get the bore smoothed out and also get a new throat that is properly aligned with the bore when rechambered properly. Any chambering that will cut away the existing chamber and throat after firelapping. These barrels usually are VERY good shooters when I'm done.....and they clean very easily too.

[gotcha]

apache, Interesting idea! ............... When you "convert" a bbl this way, do you normally cut a new crown or simply use a brass lap on the muzzle? Do you look for a used match grade bbl or have you found any old bbl is o.k. ? Have you ever tried a light smear of 600 grit lapping compound on a standard jacketed bullet for fire lapping? Lotta questions, I know, but now you've got my interest up :D Thanks again, Dale

[Apache]

Start with a CLEAN barrel!

Roll a bullet with a long bearing surface (Sierra target bullets work well) between 2 plates of steel to embed the compound into the bullet jacket. Then load and shoot it with a low pressure loading.

"WARNING"

UNDERSTAND HOW TO USE REDUCED LOADS!!! YOU CAN BLOW UP A FIREARM (OR WORSE) IF IT IS DONE INCORRECTLY!!!!

Clean the barrel well after 5 shots....you should be able to feel the difference in the bore between cleanings. A rough bore will have more friction while pushing a tight patch through it. Fire 2 more then clean again. Once it has the same smooth consistant feel from chamber to crown...it's done. You can finish it with several passes of JB bore paste on a tight patch if you want a really nice bore. Doesn't seem to make much difference in real world shooting for me though. The most shots I've had to take to get it done is 20. If it takes more than that, I consider the barrel a tomato stake. Usually less will do the job.

New crowns are almost always a good thing when done properly, one less variable to worry with. You can touch up a known good crown using lapping compound and a brass lap but a new crown is a "for sure" thing when done right. (Requires a lathe)

Match grade barrels are always lapped already....this method is for factory or A&B type barrels........or any other "cheap" barrel.

This is how I do it....and it has produced some really good results for me.....but there are other ways to skin a cat.

[gotcha]

Thanks for the thoughtful reply. The question was really concerning Savage factory barrels that were "copper mines". As you pointed out, others could benefit as well. I actually used a hand poured lead lap & 600 grit compound to clean up a MK 10 Mauser bbl (hammer forged) and it actually worked pretty well. Tho' this may have been a product of good luck rather skill ;D I've still got the compound & you've convinced me the fire lapping is a much wiser & easier alternative. Thanks for the input, Dale

[seanhagerty]

Tubbs Final Finish, if you really want to fire lap a barrel. I think I am afraid to do that to a barrel, unless it just wont shoot.

[rossman40]

As far as lead lapping I was able to see it done by a master. His big thing was sporterizing Mausers, Springfields and started getting into match rifles. The one thing that I see that is not done in shops 40+ years later is that he would always lap a barrel vertical. His reasoning was that the lapping compound would go to the bottom of the bore/lap if done while the barrel was horizontal and as a result would be uneven.

The thing that gets you with a lead lap is the change of direction. As you go thru one way and then go to pull it back the grit "shifts" exposing new cutting edges and as a result cuts more till the grit imbeds itself in the lap. That is why they cut one end and chamber the other when they lap a blank.

Now fire lapping is a bit better in that you only go one direction. The grit will be fresh starting out so it will remove more metal at the chamber end. That can be to your advantage as long as you do not destroy the throat. If you end up with being a few .0001" tighter at the muzzle that is the berries IMO.

[Ring31]

Tubbs Final Finish, if you really want to fire lap a barrel. I think I am afraid to do that to a barrel, unless it just wont shoot.

i use this... on a "good" barrel i use 1 2 3 lapping grit bullets.. not the 4 and 5's

i also have used the TMS bullets he sells, and JB paste and JB bore shine