[Unclenick]

There is some thinking this may actually be an advantage. It was started because the DDNP sensitizer used in non-toxic primers to replace lead styphnate is a more violent explosive, so the charge in a large size primer would tend to blow the primer out. The first fix was to leave the primer large but enlarge the vent (flash hole) to bleed the pressure off. Now they've just gone to the smaller primer altogether.

Then someone figured out small primers worked OK for .45 ACP because the powder volume under the bullet is so small. The roll of a primer, in addition to providing the ignition flame and sparks, is to establish the burn starting pressure, and the .45 ACP needs nothing like what a .45 Colt or a .44 Special, or any of the magnums do. Indeed, there is occasional trouble with velocity consistency in the round because large pistol primers make enough gas that they can pressurize the small volume to the point the bullet is partially or even fully unseated before the powder burn gets underway. That reduces the pressure profile of the burn. It also tends to be irregular.

So, experiment a bit. With some powders, the slower ones in particular, you'll possible find lower velocity deviation and better precision; particularly if you shoot the 50 yard conventional pistol slow fire targets.

Nick