Here's Berry's 100 grain plated HP fired from a .380 at 926 fps. It expands impressively at that velocity, but penetration is only about 8" in ballistic gel.
One could probably load it a tad bit hotter, but maybe not enough to make a difference.
Like I said, I might be inclined to load it a bit hotter in a heavier built pistol. But I'm hesitant to hot rod an LCP Max very much. The 5 grain AA #5 load with 100 grain bullets is much snappier than garden variety factory ammo, already. It's probably doing about 950 with hardcast and the soft lead, copper plated bullets from Berry's. So about 950 fps is about as fast as I care to push 100 grain bullets through the LCP Max. At 950, I feel much better with the truncated cone hardcast flat point bullet.
It's a judgement call. I may be right, I may be wrong. But hard cast bullets offer few surprises. They just penetrate.
