I owned one of the later AutoMags, with both 44 and 357 AutoMag barrels. The 44 was Magna-Ported. The guys at the local gun club loved to watch me shoot it (and the 454 Casull). I bought it back in the late 1980's with two boxes of original ammo (made in Mexico, IIRC)...
I still have some handloaded ammo for it...Lemme take a quick look...50 rds of 44 Automag, most made from 308 Win cases...20grs of 2400 w/240gr FMJ-FT...It wasn't bad to shoot, but chambering a round was a cast iron bitch...those springs were heavy...
The 308 commercial brass was a thinner gauge than the 7.62 military; made forming the 357 cases easier...I still have the 357 AutoMag RCBS die set; I rechambered a S&W N-frame 357 Mag to 357/44 using 44 mag brass run through the 357 AutoMag dies...
Ah! I still have the receipt...I bought the AutoMag through a Shotgun News ad; I paid...$1895 for it on 8/11/1989...A High Standard 44 AutoMag with a spare TDE 357 AutoMag barrel...and both RCBS die sets, spare grips, and original plastic case...
I don't know what it sold for, back in 1994...I gave all my pistols/rifles etc to a local dealer/FFL holder to sell...had to pay off doctors/hospitals...