Just fiddling through the CIP Homologation pages I came across these shotshell pressure tables:
CIP Shotshell Pressures This indicates that the max service pressure for 3 inch CIP shells is 1050 bar = 15229 PSI and the proof pressure is 19245 PSI.
SAAMI service pressures are 11500 PSI across all 12 gauge cartridges except the 3 1/2 inch cartridges. I believe SAAMI proof pressures are in the 20000 PSI range.
That is some difference between the two Max service pressures.
I have probably read the figures all wrong but in case I haven't then my questions are:
1. Are CIP 3 inch cartridges usable and safe in US made 3 inch chambered guns? (given that the proof pressures are similar they should be).
2. Have CIP superior proof pressures changed from the original British Proof house nitro proof pressures for 3 inch 12 ga. cartridges ( as in "back in Greener's day!)? (The standard proof apparently has not).
3. Given that max pressures for SAAMI specs 3 inch cartridges are only 1000 or so PSI more than the standard CIP proof at 740 bar = 10730 PSI are they safe to be shot in three inch chambered British guns with the older 1 1/2 oz = 3 1/2 tons per square inch proofs. These are built much stouter than the typical English game gun and obviously proofed for higher pressures.This does assume all guns are in proof.
4. Does anyone know what the proof pressures were for the 1 1/2 oz = 3 1/2 ton per sq. inch proof pressure was?
There is a blackpowder proof charge for 3 inch nitro proof given in Greener's book. I have no way of measuring the pressure generated nor even of getting blackpowder. Has anyone ever tried this charge for pressure?
Thanks for any and all observations and corrections.
All the best
Skeeterbd
