doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com 2.75" shells in 2.5" chambers

yall beatin dis won tu det...don u tink?

So would I, TB--but it is another factor. Right now, at least given any information I can find, the only things we know about long shells in too short chambers and/or in guns with very short and sharply angled forcing cones is that a) you can end up with blown ends on the shells; b) at least some shooters report increased recoil; and c) there is an increase in pressure, reported to be in the 1500 psi range in at least one case. We don't know that there's a velocity increase, which is the logical culprit in increased recoil, assuming shot charge weight stays the same. What we need is a volunteer with 2 .410's, one with a 2 1/2" chamber and the other with a 3" chamber. That'd tell us what we need to know about any velocity change. But unless the guns are identical in all other ways except chamber length, it would not be a good comparison as to whether recoil increases.

Since a shot charge should act as a fluid when passing from the camber/hull through the forcing cone to the constriction of the barrel we would probably experience a venturi effect where by when a fluid is compressed velocity of the fluid increases (PA24 we should have considered this earlier but your comment on flying sparked a memory from my days studying elementary aerodynamics). I really don't think that the amount of velocity increase is enough to translate to a perceptible increase in felt recoil but we may have some recoil sensitive folks out there that can detect an increase in recoil of half a foot pound or so.

Good Call Steve, yes "Bernoulli's Priciple" would take effect at any constriction which would act as a venturi and the charge would act as any fluid, as per Newton's second law pertaining to conservation of mass.....i.e. forcing cones and chokes......

Best,