The suppressed grease guns I used from 1980 forward were .45 ACP M3A1s (so post-OSS, post-WWII).
From a recovered Cold War cache. Probably emplaced in the late 1950s or early 1960s. 1-10 SFG(A), Bad Tölz, Germany. We live fired them a lot and carried them often for training missions. Just another tool in the kit. They belonged in museums due to pristine condition & rarity, but we just used them instead. Heavily. Very "007" cool at the time.
One day at the Camp Worden LTA Range, the end cap came off the muzzle of my suppressor while firing bursts. Damn thing spewed mesh washers like a roman candle as it instantly went very loud. That particular can was just shot out and the screw-on-cap had stripped threads. DXed. No source for repair parts for the suppressor.
Quiet, reliable, and fun to shoot. With all that weight plus a very slow ROF, easy to control. But also lot of weight to haul around just to fire a pistol cartridge. Our later acquired MP5SD models were far superior for the suppressed job; more portable and far more accurate due to closed bolt operation and superior sights/trigger.