Testing, testing...

[stanc]

I think that with some compromises, we could get there, although lead-free ammo certainly makes it harder.

I went back and reread what little info is available on the 7mm UIAC. It turns out that the 2650 fps published muzzle velocity is for a 16-inch barrel. (I was under the mistaken impression that it was for a 20-inch tube.) That translates to ~2750 fps out of a 20-inch barrel, with a lead-core, 130gr bullet.

So, even with the powder space used up by a "green" bullet of the same weight, it seems like it ought to still match (or at least get extremely close to) 7.62 muzzle velocities.

I'm not sure if a .422" diameter case is sufficient for the task, but it does look like the 7x46 is capable of producing the desired performance.

I guess that brings up the question, is a 25% reduction in ammo weight "good enough" to make the switch worth the costs?