And the case change is what allows you to run higher pressure.
As I've said on my bolt gun, a littler Kimber Montana I had the barrel set back and AI'd, I got 3570 fps with a 55 grain Nosler Ballistic Tip in that 22" barrel. Primers are not even close to flat, no tight bolt handles and primer pockets are tight after several loadings. Pressure equals velocity but you have to be able to handle that pressure and the improved case is magic in that regard.
On the other hand I've seen 2 grains of powder make more than 50 fps difference by itself.
