It is no secret to my friends that the M-3A1 "Grease Gun" has long been my favorite submachine gun. (It is also no secret to the ATF, apparently, since three times in the 90s snitches tried to offer me one for sale in a "can't miss" deal. Each time I picked up the phone and called the state police and the snitch went away. The devil, it must be said, knows your temptations better than you do so be prepared to resist them.)
I first fired an original M-3 back in the 70s -- a specimen that bore no paperwork since it had been stolen by someone else, who stole it from someone else, who, presumably, stole it from Uncle Sugar. This was during my Benedict Arnold period when I handled quite a lot of illegal weapons. I have loved that clunky, junky SMG chambered in the justly revered caliber of .45 ACP ever since.