3 inch in 2 3/4

[Bwillsonhunter4]

I was wondering why is it so bad to shoot 3 inch shells in a shorter chamber. I have seen it done a lot in several different guns (beretta 302 and 303, several Remington 870 wingmasters, 870 sportsmen, Remington 1100). The only problem I have ever seen from it was a extractor pin broke on a 303 but nothing else. I have or have seen probily over 3,000 rounds go through guns like this in goose loads, slugs, and turkey loads, but I have read that it is very bad and dangourouse on the internet. Why?

[bamaranger]

A shotgun shell chamber/shell is labeled according to the length of the fired shell.

Firing a 3" shell in a 2-3/4" chamber, the longer shell will unfold from the crimp and obscure the forcing cone, or initial portion of the barrel just forward of the true chamber. The shot/ shot cup/wad will have a more reduced tunnel to pass through, as the forcing cone now has the extended "flap" of the longer shell layered over it as well. That will boost chamber pressures.

Shotguns/shells, do not seal particularly well, and some of the gas and pressure generated will vent many directions, typically allowing this overcharge to occur without blowing the gun. But running over pressure rounds through any firearm is not a good idea. Operating pressures beyond those intended can shorten the lifespan of the gun. Some designs are stronger than others and I suppose could take a more of this than others. I have read of a Win M12 that was fed an incredible number of overpressure rounds at the factory and survived. I have also seen a blown shotgun at a trap shoot that let go due to undetermined reasons.

Just because an event occurs without incident ( repeated firing 3" in 2-3/4" ) does not make it a safe practice.

[darkgael]

As noted on the other forum:
Just because you can doesn't mean that you should.