BLL with 9mm 147 grain boolits not working?

[btreanor]

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!

[Ben]

Why don't you try both after your bore is CLEAN.

One or the other may offer relief.

Ben

[Yodogsandman]

Were you careful to get out all the copper fouling before shooting cast boolits? The lead can "plate" itself to any copper residue left in the barrel.

[runfiverun]

well.
I would try pushing a patch of the BLL down the cleaned barrel before your next range session.
if that looks good after shooting don't push nuthin down the barrel from then on.
if not then I would go to the traditional lube and maybe roll a light coat of the BLL on top.

[GhostHawk]

Boolit fit is king. Sounds like that one should be big enough but is it getting swagged down in loading?

Also I much prefer 2 or 3 light coats of BLL rather than one heavier one.

I have for higher velocity rifle started with Ben's Red in the grooves and a top layer of BLL.

Pull a loaded boolit and see where it is just before being fired. My guess is that is your problem.
But I could easily be wrong.

[Ben]

Boolit fit is king. Sounds like that one should be big enough but is it getting swagged down in loading?

Also I much prefer 2 or 3 light coats of BLL rather than one heavier one.

I have for higher velocity rifle started with Ben's Red in the grooves and a top layer of BLL.

Pull a loaded boolit and see where it is just before being fired. My guess is that is your problem.
But I could easily be wrong.

Some very good suggestions for all here.

Ben