I load 12 & 16 on PW 375s & 20 on an old Pacific DL-155. I'm 80 yrs old now & only load for duck & grouse hunting. I found this thread while looking for info on loading short 12 ga shells. I have a large bunch of AAs reloaded many times. I sorted out the ones with cracked or otherwise unuseable case mouths & trimmed them back to 2 3/8 in to get one more loading out of them. I can't help it, it's the Scotsman in me. I already loaded some with PB or green dot, 1 oz #8, & SSW wad from Ballistic Products. They shot great on clay pigeons & functioned the Montefeltro. It would be nice if any here with short shell experience could share it.
I think the PW 375s are the finest slngle stage loaders out there. The Pacific DL-155 is solid as a rock & serves my 20ga grouse needs. It even has the primer feed which I don' t use. Traded off my PW 800B after I stopped shooting in a trap league. Just loaded up 150 7/8 oz 20 s in paper cases. Should be enough for 2 or 3 grouse.
Bob