Quote:
Originally Posted by ED J, MORGAN
Measure your un fired 2 3/4 " shells . They are less length. so are ok for 2 5/8 chambers in 12 ga.
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The length of unfired shells is not what is important in the discussion of how long a shell was meant to be used in a chamber. It is the fired length that matters. When the crimp unfolds, if it goes too far into the forcing cone, it becomes a restriction to the forward progress of the payload, and tears at the case mouth. Pressures rise significantly when that occurs.
That said, most 2 3/4" shells I have measured don't even measure a full 2 3/4" when fired, which is what actually matters. They don't protrude far enough into the forcing cones to be a problem. Each person should measure for themselves to determine this, on the load they are interested in using. Just because most of them are short enough doesn't mean all of them are.