300, will do! It will get to my FFL Friday or Monday, and I'll measure and check then. I'm not a model 12 expert by any measure, but I think you're right on the 13 5/8 based on the research I did before buying it.
Kid, I've heard the same about hevi shot, looks like that or bismuth are my options for waterfowl, but the 3" target and game rounds are looking elusive...
13 5/8" LOP prior to 1959. 13 3/4" LOP 1960 and after.
Winchester made changes to the stock of the Model 12 duck gun after its introduction. A red rubber Winchesterre coil pad was added the first year of production. Length of pull was reduced in January 1936 to reflect the extra clothing worn by duck hunters. The drop at heel was reduced from 2-1/2 to 2-3/8 inches in December 1938.
The straighter stock reduced perceived recoil. Down pitch remained 2-1/2 inches with the 30-inch barrel throughout production. The less pronounced pistol grip-style buttstock of the original Model 12 was discontinued in late 1934 and is not found on duck guns. The new 1935-style buttstock featured a closer and fuller pistol grip. The buttstock was reshaped on Model 12 shotguns again in the mid-1950s. The late style stock featured a flared pistol grip moved back a bit from the trigger. In 1960, length of pull was increased to 13-3/4 inches on duck guns. The straight grip stock, optional from 1935, was discontinued in the late 1950s.GunDigest, July 6, 2009
