Larry;
As I believe in giving credit where credit is due, I just have to jump in here. This is undoubtably the best post I have ever seen you make.
I hope though you won't mind if I add onr little caveat. Anyone who loads & shoots old guns, Learn to look first & see just what chamber & cone is there "BEFRORE" firing that first shot. I am in total agreement that if the end is blown off "STOP", but it would have been better to have realized the chamber was short & had that abrunt step & to have never fired a longer shell in it in the first place.
I don't have any 67.5 shells to check but did quick check on a couple of compression formed 12ga 2 3/4" fired hulls, one Rem one Win & they measured about 1/32" short (2.72} or 69mm. I measured the length of a single factory loaded 2 3/4" shell having an 8-fold crimp & it went 2.325" (59mm). Note that even if the chamber (with normal cone length) did in fact measure an exact 2½' this would have an end clearence of .175" or about 4.5mm. This would be ample clearence to not impede the opening of the crimp as noted in my previous post. "This" particular shell however "SHOILD NOT" be fired in guns chambered for the nominal 2½"/2 5/8" shells Because it is a 3¼de-1oz load put up with only SAAMI specs thus not guaranteed to be low pressure.
To quote Larry here, "Its The Load" that rules this one out, not the length.
