I suspected as much.
With the can I'd probably start at 3.0 and go from there. I seriously doubt that would cycle my M&P but I'm not running a can on it either. I'd go easy and carefully. I think you'll end up somewhere between 3.4 and 3.8. I suspect the the pressure curve goes up progressively and quickly once a certain pressure is reached. But for that use it might just be stellar. It certainly seems to be with lead. Let me know how it works out.
Yeah, my experience usually has pressures peaking with lead loads slightly before jacketed. If I don't get the desired function at easy pressures and moderate velocities, I'll drop down to a 15# recoil spring.
I have a stash of Russian heavy metal free primers I'll be using for these loads. I'm hoping to wind up with a load so clean that all I'll have to do is swab the bore for copper and re-lube now and again.
