it's 3 1/2 in barrel and that is a good deal,i'd buy it in a heartbeat for a lnib,a no brainer.if you like 22 mag that is..oh ,no box,still a good buy.kinda rare.
The M-51 was never a top selling revolver but was just as well made as the other J frame revolvers. I seem to recall that the barrel was 3.5" instead of 4" and if you do decide to make the purchase be sure you have ear protection before you do any shooting with it. As usual, condition & accessories will dictate the price. Gun alone, the price seems to be at the top in my opinion!