Recently I tried a 147 grain design (Mihec) in my S&W M&P. The Mihec boolit was sized to 0.358" and the S&W M&P bore slugs at 0.356". The loaded rounds chamber and pass the "plunk" test. The Mihec boolits dropped around 0.360", then sized to 0.358", then re-lubed with the same. The powder charge was 4.1 grains of Alliant Power Pistol which is my standard load for plated 147 grain bullets.
After shooting about 75 rounds in my session, accuracy was still quite good. however, when I went to clean the gun, I noticed some very light leading in the grooves near the muzzle. The rest of the bore and chamber were clean.
Are the boolits running out of lube near the muzzle? Should I try another light coat of BLL or should I try conventional lube? I have some BAC ready to go in my Lyman lubrisizer.
Thanks!