My theory is that the long 150 Lyman 48 was made for use at the longer ranges then fired in competition. I believe that the slide was made longer than needed so that when set at the longer ranges the slide would still be in full contact with the base. This would give you the longer ranges but still have a rigid sight.

Mr. Foral wrote an article on the 48 I think I need to review it or get him over here.

MP Sadly Deceased as of 2/17/2014