Fire Lapping Bullets

  • 5.4K Views
  • Last Post 23 April 2009
BFB posted this 24 March 2009

Hi All:

As some of you may know from my intro post, I am involved in a project to fire lap some Carcano rifles that I have.

Research tells me that I need a cast bullet of around BHN 11 -12.

In slugging the bores of these rifles, I found a diameter range from .268 to .272, with most being around .269+

For the last few days I have done an extensive internet search,  and some phone calls in order to find a supplier to meet my needs. The bottom line is that so far I have come up with nothing.

I couldn't even find a mold listed that advertised a cast larger than .266

My question is:  Do any of you know of a supplier/caster that might help me out?

Any and all info is most sincerely appreciated.

BFB ... AKA  Bill

Attached Files

Order By: Standard | Newest | Votes
JetMech posted this 25 March 2009

I think you'll have to go with a custom mold and pour your own. Veral Smith at LBT can do it.

The other choice would be to use .270 bullets and size them down to .272 That might work. In any case, you'll have to make them yourself. Might as well gear up and get to it.  :coffee

Attached Files

Nora posted this 25 March 2009

I've also been trolling for CB supplies for my carcano. I've got one of these on back order. http://www.midsouthshooterssupply.com/item.asp?sku=000066.5SWED>http://www.midsouthshooterssupply.com/item.asp?sku=000066.5SWED It is suppose to drop a .268 bullet. I called and asked when the expected due date is for this mold, and was told “when ever Lee gets them to us, the order has been placed". For the price I think I can waite for it to come in.

Nora

Attached Files

BFB posted this 25 March 2009

Bill and Nora, thanks for responding.

Bill it is possible that I may need to “gear up", and in the long run, wind up shooting a harder alloy cast bullet.

My main thinking was to fire lap with a cast bullet and then shoot a “J” word .268 bullet that is available in both 140 and 160 grains.

If I wind up having to cast my lapping bullets, I may as well go ahead and get a total set up ... At this time the only useful thing I own is a set of Lyman mold handles that I use in casting pure lead for my ML.

Nora, yes, I saw the mold you speak of during my searching, and as you mention, Midsouth is waiting on Lee.

Do you know if a Lee mold would work with Lyman handles?

Regards, Bill

Attached Files

mtgrs737 posted this 18 April 2009

Bill,

You should have your .269” bullets by now, don't forget to update this thread so we all can learn the process and share in the results.  Good luck!

Attached Files

BFB posted this 18 April 2009

Yep Rich, thanks to you, the bullets are here, and they are of the Ideal diameter.

As suggested, I will try to keep this thread alive with updates.

For openers, the process is much like a barrel break in. ie: Shoot and clean, shoot and clean etc. During this phase, I will every five rounds or so,  push a lubricatied slugging bullet ,(pure lead) or a very tight patch through the bore to test for progress. You can literally feel the difference in the resistive areas.

In general, firelapping is not for the timid, and in my opinion shouldn't be done at all thru high end or match grade bores. It is however, beneficial to older military bores, and some “rough” tool marked factory barrels.

More later, Bill

 

Attached Files

cityboy posted this 18 April 2009

Firelapping kits are not cheap. A less far costly way to go is “firepolishing". Molly posted info on this in the past year, I think. Look in the Testing section. It involves coating the bore with JB bore paste and firing reduced loads using jacketed bullets.

I tried it on a 2G 03A3 barrel, and it works.

Jim

Attached Files

BFB posted this 22 April 2009

cityboy, Yes, I assume you are talking about the David Tubbs type kits.

The process I am using is somewhat more economical. Since I am a handloader, I have all the equipment/ingredients for making the lapping ammo.

 One of our members here was generous enough to supply me with the proper diameter/BHN bullets, and therefore, my out of pocket expense was to buy the abrasive compounds which I get from NECO.

 I would be hesitant to swab a bore with even a light abrasive such as JB, and then shoot through it. Although I don't know for sure, it would seem to me that the abrasive would tend to build as the bullet moves down the bore and slightly enlarge the bore (especially the lands) at the muzzle end. Also, pressure would build rather than being even throughout.

Bill

Attached Files

runfiverun posted this 22 April 2009

pressure would build and depending on the carrier you might get dieseling in the bbl too. i have polished finicky bbls by wrapping them with paper to .001 under sized and using polish on them to shoot down the bbl.i would shoot 5 then 2 without the paste. with the obduration of the soft cast bullet and the paper having just enough room to let the polish do its job. a patch was all that was needed to clean up.

Attached Files

KenK posted this 22 April 2009

I've made lapping bullets with cast and jacketed bullets and used the ready to shoot Tubb bullets.

They all worked fine for me.  I would go with cast if I were trying to cut out constrictions and jacketed, with finer grit, for smoothing.

Attached Files

Reg Lingle posted this 22 April 2009

Why not just make a lap. Easier and better! Reg

Attached Files

cityboy posted this 22 April 2009

BFB wrote: cityboy, Yes, I assume you are talking about the David Tubbs type kits.

No; I am not talking about kits. In fire polishing the abrasive is applied to the bore, not the bullet. In fire polishing a very fine abrasive (like JB bore paste) is used to coat the bore before every shot. JB is a heck of a lot cheaper than a fire lapping kit. You can find more info on polishing in the Testing Forum under “Bore Polishing (not fire lapping).Jim 

Attached Files

Largom posted this 22 April 2009

                     I have lapped dozens of barrels and every one has shown improvement. I keep a 'Tubb's Final Finish” kit of each caliber in my shop. I also use the NECO abrasives on  cast bullets and prefer these for fine polish. Every new factory barrel I own has been lapped AND a couple of custom barrels.

                     If it does'nt work now what are you going to hurt? The worst thing that lapping does is move the throat a little forward.

                      Larry

Attached Files

BFB posted this 23 April 2009

"Why not just make a lap. Easier and better! Reg"

 Yes Reg, I have hand lapped a couple, and in all truthfulness that is usually a better method  ...  Especially with new or newer factory barrels.

 The issue with the Carcano barrels that I am firelapping, is that they have progressive rifling, and therefore, as the formed hand lap is moved through the bore, it gets out of sync with the twist.  Whereas the abrasive treated bullet treats the bore in these rifles more evenly.

 Bill

Attached Files

Close