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7.62mm

scn

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I have a .308 cal. bolt action rifle that was my FIL's. In doing some cleaning/rearranging, I came across a box of Winchester 7.62mm cartridges that are 147 gr FMJ. From looking on the internet, it appears that they are OK to shoot in a .308, but wanted to confirm from our experts on here. They wouldn't be legal for any hunting, but could be used for other things.

Thanks, Steve
 
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Hunter 257W

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Not exactly. They’re loaded to different specs, with 308 being a hotter load.
Yeah but it's the same cartridge. Two shooters handload for the 30-06 and their loads vary in pressure and overall length, etc, but that don't mean they are shooting different cartridges. They can be fired in the same gun unless one of them is a nut that pushes things to the breaking point of course trying to make his 30-06 into a 300 H&H Magnum.
 

Jcalder

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Yeah but it's the same cartridge. Two shooters handload for the 30-06 and their loads vary in pressure and overall length, etc, but that don't mean they are shooting different cartridges. They can be fired in the same gun unless one of them is a nut that pushes things to the breaking point of course trying to make his 30-06 into a 300 H&H Magnum.
I’ve always heard not to fire a 308 in a 7.62 rifle. Just like you don’t fire a 556 in a 223 chamber.
 

Hunter 257W

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The chamber is larger in 7.62 and a 308 round will fit "loose" in the chamber resulting in higher than normal pressure
I've never been all that interested in military semi-autos so don't recall the exact chamber dimension differences but firing any cartridge in a chamber that it fits loose into will LOWER pressures rather than raise them compared to a tight fitting chamber. The case can expand freely to fill the loose chamber, the same amount of gas working inside a larger volume chamber gives lower pressure.
 

jlanecr500

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Pressure rating: The 7.62x51 SAMMI spec is 50,000 CUP or 58 000 psi max.
The 308 SAMMI spec is 62 000 psi max.
No big deal.

Chamber length or headspace:
The 7.62x51 chamber headspace spec is .005" longer than the 308 spec. This is to accommodate ammo made in many different countries in battle rifles.
The bottom line is: If it chambers in your gun ( bolt fully closes into battery position) then it is ok to use.
Period.
 

Wiley

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LOTS of rounds will fit chambers and the bolt close on rounds that are not for that weapon. One in particular is the M1 Garand. Regular/commercial 30-06 ammo should never be fired in one even though it’s chambered in 30-06. As to the 7.62, 308 ammo fits the chamber but is loaded to higher pressures. Every loading manual that I have points these issues out. I’ll trust those books before I take advice from an Internet forum in something that could get me maimed or killed.
 

Hunter 257W

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LOTS of rounds will fit chambers and the bolt close on rounds that are not for that weapon. One in particular is the M1 Garand. Regular/commercial 30-06 ammo should never be fired in one even though it’s chambered in 30-06. As to the 7.62, 308 ammo fits the chamber but is loaded to higher pressures. Every loading manual that I have points these issues out. I’ll trust those books before I take advice from an Internet forum in something that could get me maimed or killed.
The difference between 58,000psi and 62,000psi is within the normal variation between different loads listed in a manual for the same cartridge. There is no danger whatsoever in damaging the rifle or harming the shooter with swapping these two loads.

What you are mentioning with the Garand is true as far as long term damage to the gas system goes but it's not going to do any harm to the receiver nor is it a risk for harming the shooter. Also the context of JLanecr500's comment regarded only the 7.62NATO and 308 Winchester when he said "if it chambers and the bolt closes,, it's safe to fire".
 

Hunter 257W

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LOTS of rounds will fit chambers and the bolt close on rounds that are not for that weapon. One in particular is the M1 Garand. Regular/commercial 30-06 ammo should never be fired in one even though it’s chambered in 30-06. As to the 7.62, 308 ammo fits the chamber but is loaded to higher pressures. Every loading manual that I have points these issues out. I’ll trust those books before I take advice from an Internet forum in something that could get me maimed or killed.

I will say however that I agree fundamentally with your comment about trusting published loading manuals rather than information from a internet forum such as this. Unless you know that you know that you know you are correct stick to the manual. :) Especially when it comes to suggested load data!
 

swd

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To directly answer the OP’s question, you can safely shoot 7.62x51 in a .308.

Expanding on that answer, you CANNOT safely shoot .308 in a 7.62x51 chambered firearm.
 

GMB54

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Never had a problem with Lake City 7.62x51 ammo fired in 308Win bolt actions. Many many years ago that stuff was cheap at gun shows. Even the National Match 168gr were dirt cheap. The brass was maybe slightly thicker so reload data is not exactly the same but from a safety standpoint its safe to shoot in any modern 308 bolt action.
 
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7mm08

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LOTS of rounds will fit chambers and the bolt close on rounds that are not for that weapon. One in particular is the M1 Garand. Regular/commercial 30-06 ammo should never be fired in one even though it’s chambered in 30-06. As to the 7.62, 308 ammo fits the chamber but is loaded to higher pressures. Every loading manual that I have points these issues out. I’ll trust those books before I take advice from an Internet forum in something that could get me maimed or killed.
But you’re Wiley.......
 

DaveTN

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As has been said here, the chambers are longer on a NATO chamber. It won’t make any difference with new ammo, but you shouldn’t reload the thinner walled .308 ammo shot in a NATO chamber. It would be possible to have a case rupture. (Of course that’s a possibility with any reloaded ammo)
 

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