I pressure tested it in the same test rifle I shot the M118 SB in this morning.guess what the 7.62 CETME's MAP was? Well it wasn't below 45,000 psi and it wasn't 300 Savage level was 60,000 psi for a test string of 10 cartridges (I will post the Oehler data sheet for the non believers if they'd like?). We all know the 7.62 CETME is a low pressure load to be safe in those rifles which were only designed for 45,000 psi.right? Well I happen to have come across a quantity of original Spanish made in 1962 7.62 CETME ammunition. I'm sure you've all heard that one as it is repeated often on this forum. I have found several non NATO spec 7.62 cartridges that generates 45,000 to 53,000 psi for use in those countries with HK M91s and for one country that had FN-FALs.Īnother "truth" that has been told so often about the FR7 and FR8 rifles is they were "designed for the 7.62 CETME cartridge". I've yet to find a milsurp 7x57 the generates less than 51,000 psi. Seems to me there would be a lot of blown up SR Mauser rifles if they were "only safe for 45,000 psi". European factory loads for the same cartridges have essentially the same MAPs as their milsurp counterparts. What I do know is I have measured the psi of numerous milsurp cartridges made for SR Mausers (6.5 Swede, 7x57 Mauser, 7.62 CETME, 7.65 Belgian and 7.65 Argentine) dating back to 1918 (Spanish made 7x57). So where does the 45,000 psi come from? Darned if I've been able to track it down, that statement has been repeated so often it's become the "truth". Cartridge design was in it's infancy and cartridges were loaded to be safe in the actions they were made for. Mauser designed and made the SR Mauser actions as strong as he could given the metals and technology of the day. This brings us to another untruth told so often every one believes it "Mauser designed the SR actions for 45,000 psi".Problem with that is Mauser did not measure "psi"s and even the CUP method of chamber pressure measuring was not in use then. Just this morning I measured the psi and velocity of my reference lot of M118 SB. 308W and 7.62 NATO overlap so much it is almost impossible to say which actually has the higher psi.
308W factory rounds and find the actual lot to lot MAPs of. and foreign 7.62 NATO cartridges and numerous. Thus in reality we have very close MAPs of 50,000 and 52,000 psi with both measured by the same. If we look further into SAAMI information we find they also list a CUP MAP for the. The psi MAP for the 7.62 NATO is from 1950s Copper Unit Crusher (CUP) psi measurement. 308W measured with modern transformal peizo-transducers. So what is misleading about that? It's apples vs oranges the SAAMI MAP for the. Military spec MAP quoted for the 7.62 NATO is 50,000 psi. The data he gives is essentially correct but it is misleading. 308W generates a lot more pressure than 7.62 NATO. Unfortunately Dutchman repeats data, by quoting other sources, attempting to show that. However the second method was to rebarrel the M95s with a new 7.62 barrel. M95 Chileans were converted to 7.62 using two methods first was, as the link to Dutchman's article shows, was by drilling out the 7x57 chamber and solder/brazing an insert in it, reboring and rifling the barrel to 7.62 and then rechambering to 7.62 NATO. First of all let me say I'm not accusing anyone of is the point of the quote I'm making.