Keeping in mind the Rohrbaugh is actualy a calibre un to itself, ( No +P or +P+ ammo) in standard 9mm X 19 (Luger/parabellum) only, I have opted for the heavy bullet. If these keyhole on me so much the better as the 147 grain has more length to tumble than others. The original 9mm X19 load was a straightend .30 Luger case with .38 cal ( 355) bullet, designed to operate at a MAX ( read red line) C.U.P. of 40,000! Today, +P+ and "NATO" rounds often have this level of presure but im sure you already know that, along with European 9mm ammo is almost always loaded hotter as well.
Here in the states, the .45 a.c.p. has traditionaly been the "meat and potatoes" handgun load ( in auto form) and as such, 9mm ammo here has always taken a back seat to research, development, etc. Most "standard" 9mm ammo is at peak pressures of 33,000 C.U.P. with the "Hot new" .40 S&W and .357 Sigs generating upwards of 37,000 C.U.P.
What all this means is basicaly if the R-9 were able to withstand such higher pressure extremes you'd probably see models offered in these two calibres. This seems to be the reason behind the latest "whopla" over the .45 G.A.P. project. Yes the .45 A.C.P. operates at very low pressures and as such a .45 G.A.P. is certainly possible due to the similarity in operating pressures, coupled with a shorter over all length more condusive to being stuffed in a 9mm size frame, But ill lay odds the .380s will make an appearence first.
