I built one in 450 bushmaster. I chose that over the 458 socom because the 450 bushmaster shoots .452 bullets (same as 45acp and often available in bulk for much cheaper than .458). Mine is 16" and I shoot subs with a can.
FYI a 230 gr .452 speer gold dot HP, shot subsonic, will pass clear through a coyote broadside at 60 yds and leaves some internal stuff hanging about 3" out the exit hole.