My question is what suffers? When you interject something else into the equation, there has to be an action/response. I'd guess the pattern suffers, but how much? Has anyone tried to pattern U.S. of A. #2s or #4s with 70mm cartridges in a 65mm chamber?
Kind Regards,
Raimey
rse
At least with paper shells, Raimey, the patterns actually improve. Back when the conversion was made from short to standard 2 3/4" chambers in this country, it was standard practice for some of the top trap shooters to shoot longer shells in shorter chambers. The case mouth, opening slightly into the forcing cone, cushioned the shot (not protected in a plastic shot cup back then) on its initial contact with the bore. Of course that's no longer a problem with plastic wads/cups, but I don't know why a plastic hull opening slightly into the cone would hurt the pattern. According to the author of the article that's the source of this information (American Rifleman from the 30's) who was a long-time employee in the American firearms industry, there were several gunmakers who were actually short-chambering their 2 3/4" shotguns in order to give improved patterns with the ammunition then available.
Here's one example I have, from some patterning I did. Shells were fired in an Army & Navy with 2 1/2" chambers and factory forcing cones, barrel choked .004 (skeet), at 25 yards. The first was a Westley Richards 2 1/2" shell with 1 1/16 oz nickel-plated British # 6 shot; the second, my own reload in a Federal Gold Medal 2 3/4" hull, 1 1/8 oz American # 6 shot, standard lead. The WR patterned 62%, the Federal reload 75%. In both case, I did pellet counts on the shells in question before patterning in order to get accurate percentages. (Just found a 3rd example, same gun, same distance: Eley Grand Prix 2 1/2", 1 1/16 oz Brit 6's: 66%. Interestingly, while the Grand Prix had a fiber wad, the WR had a plastic wad (as did, of course, the Federal reload.)
