doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com 2" 12ga vs. 2.5" 12ga prices

Would the chambers be sized for a roll crimped shell, or a fold crimp? Or, would it depend on when the gun was made?

Moden guns seem to be chambered for fold crimped cartridges. Funny thing is I haven't seen modern roll crimp cartridge except for buckshot & slugs and seem to recall that unfired European BK shot roll crimp cartridge is usually longer than fold crimp suggesting fired cartridge maybe same or very similar. I am totally unfamiliar with case length of old roll crimp cartridges.

My hull length is typically shorter on a roll crimped load as opposed to a star crimped load of the same recipe. On a roll crimped hull, I want the hull's open mouth to be .25" above the osc for a neat, tight crimp. A star crimp typically needs more hull length above the load.

The length of a shotshell is based on their fired length. Assuming both shells are nominally 2 3/4" long then a loaded Roll Crimp shell will be longer than a loaded fold crimp shell. Depending upon your viewpoint the roll crimp shell either requires or allows a longer wad column. The old roll crimp 2 5/8" shell had approximately the same loaded length as a 2 3/4" fold crimp shell thus about the same internal capacity. Most hulls will not measure exactly what their nominal length calls for, quite often running a bit short.