What is the difference between 7.62x51 and 308?
Is 7.62x51 safe to shoot in a rifle marked 308 win?
Is 7.62x51 safe to shoot in a rifle marked 308 win?
Range Report 7.62x51 308
- Thread starter chadg
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Re: 7.62x51 308
Chamber an pressure to first question, and yes to second
Chamber an pressure to first question, and yes to second
Re: 7.62x51 308
Chamber pressures are virtually the same... the difference is an internet myth due to differences in the pressure testing system. I have personally contacted several manufacturers with this same question.
You can use normal loads in both interchangeably, provided that the 7.62x51 fits in a 308 chamber. Some (very few) makers still make the external dimensions of 7.62 NATO just a bit on the large side, and it may have problems in a tight 308 chamber. Normally a commercial 150 gr 308 Win load is about the same as 7.62 NATO Ball.
Even though the chamber pressure is the same, the pressure vs time curve is different in some loads: "light magnum" loads by hornady and federal have slower powders than normal loads, and can accelerate wear on a semiauto. Some 308 loads also are loaded with heavier bullets than NATO ball (which is around 143-150 gr) has the different port pressure can also have wear or functional problems in some gas guns.
Chamber pressures are virtually the same... the difference is an internet myth due to differences in the pressure testing system. I have personally contacted several manufacturers with this same question.
You can use normal loads in both interchangeably, provided that the 7.62x51 fits in a 308 chamber. Some (very few) makers still make the external dimensions of 7.62 NATO just a bit on the large side, and it may have problems in a tight 308 chamber. Normally a commercial 150 gr 308 Win load is about the same as 7.62 NATO Ball.
Even though the chamber pressure is the same, the pressure vs time curve is different in some loads: "light magnum" loads by hornady and federal have slower powders than normal loads, and can accelerate wear on a semiauto. Some 308 loads also are loaded with heavier bullets than NATO ball (which is around 143-150 gr) has the different port pressure can also have wear or functional problems in some gas guns.
Re: 7.62x51 308
Erik, very informative read......Thanks.
Erik, very informative read......Thanks.
Re: 7.62x51 308
Hey no problem bud. I didn't feel like writing something like that out when someone already took the time...haha.
Hey no problem bud. I didn't feel like writing something like that out when someone already took the time...haha.
Re: 7.62x51 308
Yup, I've been preaching that gospel for more than a decade now.
Ran QuickLOAD on some .308 loads that were published in the 1980s with CUP pressures, known to be safe with M14 gas systems, and they correlate quite nicely with the general idea that 52KSI CUP is about 60,190 KPSI Piezo CIP. I can't find it now, but the article that even had M14 port pressures (highest with 45.5 748 and 150-gr SMKs and LOWEST with the 190s, BTW) shows an almost even 2,000 PSI difference between old CUP and new CIP Piezo at the 12,500 PSI, +/- 2,000 port pressure standard for that rifle, at 12.5 inches bullet travel to reach the gas port.
Shorter case life, yes. Pressure incompatibility, no.
But I still haven't ever seen ammo dimension specs with minimum AND maximum tolerances for either cartridge.
As far as the chamber dimension differences, I won't discuss them with anyone who has not pulled out a dial caliper and LOOKED at the "difference" dimensions of .005 and .0065 and possibly .0075.
Yup, I've been preaching that gospel for more than a decade now.
Ran QuickLOAD on some .308 loads that were published in the 1980s with CUP pressures, known to be safe with M14 gas systems, and they correlate quite nicely with the general idea that 52KSI CUP is about 60,190 KPSI Piezo CIP. I can't find it now, but the article that even had M14 port pressures (highest with 45.5 748 and 150-gr SMKs and LOWEST with the 190s, BTW) shows an almost even 2,000 PSI difference between old CUP and new CIP Piezo at the 12,500 PSI, +/- 2,000 port pressure standard for that rifle, at 12.5 inches bullet travel to reach the gas port.
Shorter case life, yes. Pressure incompatibility, no.
But I still haven't ever seen ammo dimension specs with minimum AND maximum tolerances for either cartridge.
As far as the chamber dimension differences, I won't discuss them with anyone who has not pulled out a dial caliper and LOOKED at the "difference" dimensions of .005 and .0065 and possibly .0075.
