Just just ran across a similar situation.

I've been using Xtreme's bullets for a long time without issue in my S&W's with EDM/ECM rifling... until a few weeks ago when I loaded up some work-up loads using Xtreme's 240gr RNFP for my new M69.

All taper crimped. I've loaded many hundreds of these & with powder charges that I have tested the most accurate. All in the 1000-1100 fps range.

I started noticing lead deposits on the chamfered muzzle of the new M69, & my 629-6 I was shooting as a comparison. The 629 had rifle leading the last ~2" of the barrel. The M69 had it just the last <1". Both had it splattered on the muzzle too. The 629 was the worst.

I just reloaded (100) more work-up loads & gave them extra light taper crimps. I've never had this with any Xtreme bullets before. I've always used a moderate taper crimp. If they still have the same trouble I have to assume something changed with how they're making the bullets? Don't know, this is strange.

I'm going to the range this week to try them.

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Waiting for the break of day