72Stick 0 Posted October 30, 2010 Report Share Posted October 30, 2010 Does anybody know where I can find the max chamber pressure for the S12? Quote Link to post Share on other sites
Paulyski 2,227 Posted October 30, 2010 Report Share Posted October 30, 2010 Does anybody know where I can find the max chamber pressure for the S12? To the best of my knowledge, nobody has measured it. On the other hand, people have severely overgassed their guns, then shot magnum loads & the chambers never had issues... The carriers & op-rods do eventually get damaged though. Quote Link to post Share on other sites
skiboatsp 111 Posted November 1, 2010 Report Share Posted November 1, 2010 Does anybody know where I can find the max chamber pressure for the S12? To the best of my knowledge, nobody has measured it. On the other hand, people have severely overgassed their guns, then shot magnum loads & the chambers never had issues... The carriers & op-rods do eventually get damaged though. How would the gas block effect the chamber? Quote Link to post Share on other sites
72Stick 0 Posted November 2, 2010 Author Report Share Posted November 2, 2010 Most guns have a max safe operating pressure in the chamber. I'm not sure if the gas block would have much effect on the chamber pressure. By the time the gas reaches the gas block the peak chamber pressure should have been reached. My concern is for the max safe chamber pressure at it's peak. Quote Link to post Share on other sites
smartbomb 133 Posted November 2, 2010 Report Share Posted November 2, 2010 (edited) there is is a thread running on another forum where one of the builders (very good at that) is trying some large caliber ak conversions. there is some real detailed info on chamber pressures. i wrote an app that compares some pressures and the thrust on the bolt. the next step is to calc the lug shear and flex. i stuffed the app on my wifes domain so you could get to it with a browser. http://www.tallycoupondiva.com/BOLTTHRUST3.html its pretty self explanatory. columns on left are filled with random default data and can be changed with whatever. on the right the fiels allow you to add cartridge chamber pressure and case head diameter and it will calc the bolt thrust. if you want you can cut/paste into left columns and replot. Edited November 2, 2010 by smartbomb Quote Link to post Share on other sites
rjrivero 50 Posted November 2, 2010 Report Share Posted November 2, 2010 (edited) Chamber pressure is a function of the ammo, not the gun. The SAAMI Ave. Max chamber pressure for 12 ga is 11,500psi. For a 3 1/2" Magnum is 14,000psi. Proof loads are generally 60% more than that. I don't think this is what you're really asking for. If you could let us know what you're really after, I'm sure we can help you figure it out. RJ Edited November 2, 2010 by rjrivero Quote Link to post Share on other sites
smartbomb 133 Posted November 2, 2010 Report Share Posted November 2, 2010 rj he may be looking at what the trunnion/barrel/bolt will withstand. typical 762x39 runs pressures around 45k psi and the everything remains intact. say i want to convert my ak to a 7mm-08. can the above parts handle the increased pressure? dont know of any empirical testing. so its a crap shoot. Quote Link to post Share on other sites
72Stick 0 Posted November 3, 2010 Author Report Share Posted November 3, 2010 SAAMI, that's the acronym I was trying to remember! Thanks for all the good info. I've been reloading pistol and rifle ammo for about a year. I just started researching reload data for shotguns and their a little different. I have powder data from Alliant and Hodgdon. Any suggestions on powder and wad combos for our S12s? Quote Link to post Share on other sites
msrdiver 42 Posted November 6, 2010 Report Share Posted November 6, 2010 I got data on my own 12 pellet 1 buck reloads. I like my 1414 fps and 7600 psi loads very much. Keep in mind that about 7fps is lost for every inch of barrel less than 30 inches (test barrel length). I also have data for two 16 pellet 1 buck loads. The two 16 pellet loads are actually a primer substitution test comparing Remington 209P and Federal 209A primers. What are you looking to reload buckshot or target shot? You are better off buying bulk packs than starting up reloading if you are shooting less than THOUSANDS of shells per year. Look in the reloading section for the cost breakdown. Now imagine the time spent reloading versus shooting. Quote Link to post Share on other sites
psl sniper 963 Posted November 6, 2010 Report Share Posted November 6, 2010 I got data on my own 12 pellet 1 buck reloads. I like my 1414 fps and 7600 psi loads very much. Keep in mind that about 7fps is lost for every inch of barrel less than 30 inches (test barrel length). I also have data for two 16 pellet 1 buck loads. The two 16 pellet loads are actually a primer substitution test comparing Remington 209P and Federal 209A primers. What are you looking to reload buckshot or target shot? You are better off buying bulk packs than starting up reloading if you are shooting less than THOUSANDS of shells per year. Look in the reloading section for the cost breakdown. Now imagine the time spent reloading versus shooting. im interested in the data you used to achive these results. been reloading for a few years just started 12 gauge last weak. 1 Quote Link to post Share on other sites
1mile50 102 Posted November 7, 2010 Report Share Posted November 7, 2010 rj he may be looking at what the trunnion/barrel/bolt will withstand. typical 762x39 runs pressures around 45k psi and the everything remains intact. say i want to convert my ak to a 7mm-08. can the above parts handle the increased pressure? dont know of any empirical testing. so its a crap shoot. You would have better luck converting the .308 Saiga to 7mm-08. Everything is wrong for a 7mm-08 conversion from a x39, the size of the bolt face, length of the action, and on and on. Quote Link to post Share on other sites
smartbomb 133 Posted November 8, 2010 Report Share Posted November 8, 2010 rj he may be looking at what the trunnion/barrel/bolt will withstand. typical 762x39 runs pressures around 45k psi and the everything remains intact. say i want to convert my ak to a 7mm-08. can the above parts handle the increased pressure? dont know of any empirical testing. so its a crap shoot. You would have better luck converting the .308 Saiga to 7mm-08. Everything is wrong for a 7mm-08 conversion from a x39, the size of the bolt face, length of the action, and on and on. i was going with a psl kit for the conversion. at this point its all vapor. i am hoping to get the psl kit next month. i will have this and an x25 project to get me thru the winter. Quote Link to post Share on other sites
Paulyski 2,227 Posted November 8, 2010 Report Share Posted November 8, 2010 Does anybody know where I can find the max chamber pressure for the S12? To the best of my knowledge, nobody has measured it. On the other hand, people have severely overgassed their guns, then shot magnum loads & the chambers never had issues... The carriers & op-rods do eventually get damaged though. How would the gas block effect the chamber? Oops. I was misinterpreting the question as referring to the gas chamber, not the breech. I've been brainstorming ideas on measuring gas chamber pressures & flow rates with differing port combinations in order to formulate formulas for differing barrel lengths.... Just a dream, but it's been on my mind. Being as Email notifications have been down as of late, I wasn't aware that my post was quoted. Sorry for the delay in clarification. Quote Link to post Share on other sites
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