Originally Posted by rockquarry

Granted, between alloy mix and diameter, diameter is often the more critical of the two, but the alloy mix remains important for best results. If they'll also provide a choice of alloy mix or at least something that's not too hard, then that would be a good place to start if you're going to stick with a commercial source.

I don't know anything about Penn bullets, but there are always exceptions and a sample of what they have available would certainly be worth trying.