Lapping a barrel?

[Scota4570]

Real deal cast lead lap pushed by a big beefie steel rod. 

I got a brand new 45 cal barrel that shoots poorly.  I have lapped several barrels.  Figured it can not hurt to try on a tomato stake.  It had definite tight spots in the middle and the muzzle was loose.  No wonder it does not shoot.   Trouble it the grit I have cuts super slowly.  It is water based permatex valve grinding compound in a tube.  I also tried #120  aluminum oxide powder with poor results.  I worked it for several hours and made no real progress.  I want a choke when I'm done.  Thousands of strokes in not in my playbook.

I used clover valve grinding compound in the past.  The coarse side of the  tin cut pretty fast.  I could make a choke and smooth up the length of the bore pretty quick.  Then fine side was good to finish.  I still have some clover #320 but that is for finishing not significant material removal. 

What compound should I buy?  Silicone carbide in grease?  Whose?

[FlintFan]

Why not buy the Clover compound again? 

[rich pierce]

I would freshen the bore with cutters. I don’t think lapping will remove much or give significant choke. Freshing a rifled barrel is easy if all you’ve got is a couple tight spots. 2 hours to cast the lead and make the cutters for grooves and lands, then an hours work should do it.

I thought it was complicated till I tried it.

[Scota4570]

Unless it shoots after yesterdays session I may try actual freshing with a cutter. 

In the past I have used 100 or 120 clover to make a significant choke.  It is probably only a few ten thousands.  But enough that the lap could not be pushed out the muzzle.  That small amount was enough to make loading easy and they shot really well.  I then worked down to 320 to make a very fine polish. 

No body in may area has lapping compounds,  I'll order some.  Silicone carbide in grease?

[rich pierce]

Good luck with it.  I’m getting close to restoring an original barrel to shooting.  A friend re-breeched it beautifully and put in a new drum.  Building the lock now to fill the mortise and then it will b3 time for shooting!

[Scota4570]

I shot it over the weekend and posed a couple of excellent scores.

I got my lapping compound in the mail.  I can not leave well enough alone.  So, I used #100 to take the tight spots out and make a slight choke.  I polished to #320 with more laps.   The factory crown was cockeyed.  I fixed that.  The barrel is a little bowed or the bore not straight.  Once I compensated for that I was able to make a concentric crown in the lathe. 

Time to try it out.   

[rich pierce]

Glad it’s shooting great!