Gee, Piggy, you stole my line!
The 10mm, in most loading manuals, is almost a mirror of 40 S&W. Maybe 100 FPS advantage to the 10mm, but usually test fired from a longer barrel too. Where the 10mm really out shines the 40 S&W is in high velocity rounds. Those require the use of slow burning powders like Accurate #9, IMR 800X or Blue Dot. These slow burning powders need longer barrel lengths to achieve full burn. If you can't get a full burn, there is no real big advantage. Lot of pop, flash and maybe a few FPS, if you are lucky. Apples to apples, factory chart. A 180gr bullet fired from a 40 S&W travels at about 985 to 1015 feet per second. The same bullet fired from a 10mm travels about 950 to 1030 feet per second (Gun digest 1999).
I like 10mm, have a 610 with a 6 inch barrel. Spent the summer playing with loads, shooting 40's in the gun, did lots of stuff. The only time that there was a significant advantage to 10mm was when slow burning powder was applied. Those same 180 grain bullets traveled at over 1350 feet per second. Now, that is a advantage that cannot be achieved by any 40 S&W.
Mallron, you are correct, there is still plenty of velocity and energy behind that bullet, and so does the 40 S&W too. At a lesser cost per round, less recoil and lots less flash.
Robert
