What dimension is that?  My Sierra manual has .473" for mouth diameter.

And what do you use for 40S&W, 9mm & .380auto?

http://www.saami.org/


Varying case mouth diameters from SAAMI spec are result of varying bullet diameters and brass wall thickness that are not SAAMI spec. Such as with 45acp bullets, both .451 and .452 bullets are common. Nickel plated brass has a thicker wall than non plated brass. Sierra's recommendation of .473 is worrisome for most pistol chambers and most likely require your chamber to be reamed to accommodate. Be a tight fit. .470 or .471 is where I like to see my 45acp case mouth diameter at for feed ability. .473 would have to be a diameter for maximum seal to achieve max accuracy.

What ever the manual says is the case mouth diameter subtract .002 or .003 from that and crimp to that diameter.