The CS-1 was the brainchild of the then Commissioner of Customs, Von Rab's assistant who wanted to arm their inspectors. He actually gave S & W the specs. for the b/c gap of .002", and S & W told them the guns would not work - never mind, just build them. Well they all had to go back to S & W at least once, and many twice. They were about as useful to an inspector or agent as a boat anchor due to their weight. The inspectors got the 4", and the agents got the 3". Don't get me wrong, these are some of the finest revolvers S & W has built in the past 3 decades if you ask me. If I ever find a good one at a fair price I will buy it.