chamber lengths

[William Woods]

Having followed the thread on the "P" designation guns, and not wanting to lengthen the thread further, I had some additional questions regarding the reproductions.

I have seen twenty gauge reproductions with both 2 3/4" chambers and those that have 3" chambers. What, if any other, requirements were there for the 3" chambered guns? Did the barrel lengths/choking determine the chamber length? Were there shorter barrel lengths, more open chokes, that had the 3" chamber?

Previously, I had asked the question about what determined the "P" designation on a reproduction? How many guns produced with certain specifications be designated a "P" gun? Say a twenty-eight gauge with double triggers, beavertail forend, and twenty six inch barrels, how many produced wih those specs be designated as prototypes?

Thanks to all.