I used to have a Sig P226. I let it go in the caliber consolidation effort when I got out of the .40S&W game, along with my H&K USPf and XD-40. Great gun, but the grip was pretty fat.
This is the same condition as the 5.56x45mm versus .223 Rem. The NATO rounds (5.56x45 and 7.62x51mm) are a little higher pressured. Anything rated for 5.56 or 7.62 can shoot the .223 and .308 counterparts, but not vice versa.
The Houston Gun Collector's Association is having the big bi-annual gun show at the Reliant Center this weekend. Can't wait, I seem to have an itch for a new shorty, not sure what yet though. <thumbsup>