I have one of those, 1984 birthdate, outshoots every Sig P226 I've owned even my last one I collected SAO rail frame. I bought it for $600 with 2 mags in the original box with the red velvety padded interior (old school sexy lol) back in about 1995. The research I did about these pointed to a crate of ammo the RCMP acquired from the Armed Forces QM's. This ball ammo was 9mm loaded specifically for use in sub-machine guns like Sterlings firing from an open bolt not sidearms because it was way too hot. It was so old they probably got it for a bag of pucks and a flag. I've fired a few vintage 9mm rounds from 1943 and a little later that had no NATO circle-crosshairs on the headstamp and it was easy to tell they were wicked hot. Sorted them all out into an ammo can of their own for use only in my 2 PCC's.