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SAMMI pressure chart

3K views 11 replies 7 participants last post by  geometric 
#1 ·
Anybody know where I can find the SAMMI data for sh :shock: t guns. I used to find it with the powder manuf. paper data. I've run several searches on this site and on the web to no avail.

I'm primarily looking to see what the 12g 3.5" rating is, but really would like to see it from sammi.

Thanks in Advance!
 
#7 ·
What about the chamber test pressures of the major firearm manufacturers? Is there any data out there showing these test pressures? I would think it should be close to at least twice the normal maximum cartridge / shotshell pressures.
Also, is there a formula for converting C.U.P. to P.S.I.?
Thanks.
 
#8 ·
aerod1 said:
What about the chamber test pressures of the major firearm manufacturers? Is there any data out there showing these test pressures? I would think it should be close to at least twice the normal maximum cartridge / shotshell pressures.
I'm not the one in the know, but I'd say the SAAMI guide lines set the pressure maximums. Now the Gun manufacturers could build to a higher standard, but the standard is the job of the SAAMI group. If they did build to higher pressures I wouldn't think they'd acknowledge that pressure. Doing that might encourage someone to pack more powder or other experimental components into a home brew and severly exceed the SAAMI max.

aerod1 said:
Also, is there a formula for converting C.U.P. to P.S.I.?
Thanks.
From what I read I don't think a formula exist.

SW
 
#10 ·
EVERYBODY feels better if pressure is within SAMMI pressure limits & indeed, there is little reason to exceed SAMMI presure limits as very good loads can be built in all gauges without exceeding their guidelines. The SAMMI guidelines are in general, more conservative & less complicated than the cup equivalent. The quality & strength of shotguns varies greatly. A good quality 10 ga. is not even working up a sweat at 11,000 psi. Most are so massive that twice that pressure is not enough pressure to flex the chamber & barrel, yet there are others with headspace problems that should not see the 11,000 psi max. Some of my 10 ga. doubles have three times the metal in the barrels & chamber than 12 ga. guns. The 10ga. guns that are built like a tank were built like a tank for a reason. They were made for heavy loads & to absorb a lot of punishment & most of them are up to the challenge. I have commented in depth about the cup system, but it is a bag of worms. There is nothing wrong with the system itself, but the problem comes when you try to compare / convert it to the SAMMI equivalent.
 
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