I spend a lot of time over at Doublegun and this comes up quite often and I gather it does raise pressure, how can it not when your openning the crimp into a much smaller area and have to compress the charge to get through it. The amount of increase might not be large but it might be enough that shells loaded to max pressure then go over. Why take a chance with a fine old gun that is nearly irreplaceable. 2 1/2" shells are readily available(RST, Vintagers, Kent and others) plus BP has plenty of data as do some of the powder companies. MEC Makes an adaptor to load 2 1/2" fold crimp shell on their presses(I load 2 1/2" 16ga and 12ga on my MEC 600). Roll crimp heads are also available from a few suppliers and you can load new primed hulls without a press, new 2 1/2" hulls available from a couple of places).
I don't even bother with 2 3/4" shells anymore as 2 1/2' work just fine in my 2 3/4 and 3" guns. My duck/pheasant load is 7/8 or 1 oz of ITX or Bismuth or 1 oz of lead 5's where I can use it, coyotes get either and ounce of NP BB's in the 16ga or 1 1/4 ounce of the same in the 12. 3/4 ounce of lead 8's break clays in either.
Last edited by erich; 05/09/18.
