Maybe I’m the oddball here. But I have conversions to shoot the Uzi in .40, 10mm, .357 Sig, and .45ACP. But I find I shoot the gun 95% in 9mm, 4.5% in .22LR, and the other 1/2% in the other calibers.
And yes, a tweaked grease gun mag will hold 35 of the .40/10mm and they run pretty well