Story, concern and question on M70 scratched barrel

[PJGunner]

I've only fire lapped one barrel, my M70 FWT 7x57. Never saw a barrel that would foul as bad as that one. Used the NECO kit and rather than jacketed bullets I used hard cast well imbedded with the various grits. Instead of ten round each I ran five each. Seems to have turned the trick and now I can shoot quite a bit before having to clean it down to bare metal. If a gunsmith using a lead slug to lap a barrel then why wouldn't a cast bullet with the grits imbedded not do a good job?
Paul B.

 

[FOTIS]

Did the same thing to a friend's Taurus 38 last week!
His snubby had a hellacious scratch in the barrel. So bad that 7 yards groups looked like 50 yard 12 gauge 00 buckshot patterns!

I loaded some soft casts and we applied the firelapping compound on the bullets. After 15 bullets the rifling was smooth and the scratch gone.

I shot a 3" group at 25 meters with it last weekend with crappy 158 gr cast bullets!