Just to Make Sure I Don't Blow Something Up

[DavidCBaker]

From everything I read, I can shoot a Winchester 7.62 147 gr FMJ in my a rifle that's chambered for .308, right? I don't want to be nervous when I pull the trigger tomorrow.

[Guest JHatmaker]

Yes, they just say not to shoot .308 in a 7.62 (kinda like the whole 5.56/.223 thing)

[DavidCBaker]

Whew. Thanks!

[MacGyver]

It's actually the reverse of the .223/5/56 argument. It's okay to fire 7.62 in a rifle chambered for .308, but may not be okay to fire .308 in a rifle chambered for 7.62. While they are approximately the same size dimensionally, 7.62 is spec'd to have a thicker wall thickness. There probably wouldn't be a problem with a newer rifle, but in an old Mauser or something similar there could be.

Here's a link if you are interested:

7.62x51mm NATO or 308 Winchester? What's the Difference?

[Motasyco]

Could someone elaborate on the .223/5.56 thing. I don't want to blow up either. I've been shooting 5.56 in my M&P15.

[Guest JHatmaker]

It's actually the reverse of the .223/5/56 argument. It's okay to fire 7.62 in a rifle chambered for .308, but may not be okay to fire .308 in a rifle chambered for 7.62. While they are approximately the same size dimensionally, 7.62 is spec'd to have a thicker wall thickness. There probably wouldn't be a problem with a newer rifle, but in an old Mauser or something similar there could be.

Here's a link if you are interested:

7.62x51mm NATO or 308 Winchester? What's the Difference?

That's what I stated above. You can shoot 7.62 in a .308, similar to how .223 can be shot in a 5.56, but not the other way around if the rifle is chamber only for .223.

Edited July 10, 2009 by JHatmaker

[strickj]

Could someone elaborate on the .223/5.56 thing. I don't want to blow up either. I've been shooting 5.56 in my M&P15.

If your rifle is marked 5.56 then you may shoot both 5.56 and 223.

If your rifle is marked 223 then you may only shoot 223.

[Motasyco]

If your rifle is marked 5.56 then you may shoot both 5.56 and 223.

If your rifle is marked 223 then you may only shoot 223.

I ran (well, actually walked fast) to the safe to check and I couldn't find it on the rifle but I checked the S&W website and it says 5.56 or .223. I guess I'm safe. Thanks!

[MacGyver]

Sorry for the confusion Hatmaker, I wasn't criticizing your post. Since David asked about shooting 7.62 in a .308 - that is the reverse of the .223/5.56 argument. You can shoot either in a rifle marked 5.56, but not shoot 5.56 in a .223. Unlike the 7.62 where depending on the vintage/headspace you can get in trouble shooting commerical .308. I should have been more clear in my post.

[Garufa]

M1 Garands and M1A's have a gas system designed for a specific pressure and bullet. The GI issue rounds for those rifles are loaded to a LOWER pressure than commecial rounds which are usually designed for more hunting-oriented shooters. Higher pressure.

Garands in particular are prone to ruination with continued use of high pressure commercial rounds. Basically it bend the operating rod. Adjustable Gas-plug can be installed to prevent this. I assume M1A is the same - have no experience with them.

Fast forward to the 5.56/.223. The AR, NATO or whatever you call it 5.56mm is much higher pressure than the commercial .223 round. Guess it has to be to make that teeny boollit do anything.

[Mike.357]

Garands in particular are prone to ruination with continued use of high pressure commercial rounds.

Prvi Partezan sells a 150 grain 30-06 that works well in Garands near as I can tell.

Felt recoil is definitely lower than M2 ball ammo. The round also looks identical

but to be safe I will stick to shooting them out of Garufas Garand.

[Guest gcrookston]

Hatmaker has a pretty good answer to the problem, but let me elaborate. About the time 7.62x51 Nato was introduced, .308 was introduced commercially. It had thinner walls on the brass and so there could be an issue of expansion (worst case scenario, stuck brass).

When .223 was introduced the pressures were much lower than when the 5.56 Nato came out a few years later.

Throughout the 60's and 70's and into the early 80's it was not safe to interchange either the 5.56 or 7.62 with it's civilian counterparts .223 or .308.

However, I personally have shot much of these contrary calibers in guns made after 1985 with not ill effect and don't hesitate to recommend you all do the same. But, let me warn you, I have witnessed a 1960's vintage M700 barrel in .223 that failed a 5.56 round (the receiver was fine) and like wise I have experienced split cases of 308 in an Armscorps M14 receiver/GI barrel.

I have a Savage .223 that will eat anything you can feed it (made circa 1995) and a Springfield Super match with a Krieger 7.62 barrel that lives on .308 Federal Match for sub-moa groups...

[Guest JHatmaker]

Sorry for the confusion Hatmaker, I wasn't criticizing your post. Since David asked about shooting 7.62 in a .308 - that is the reverse of the .223/5.56 argument. You can shoot either in a rifle marked 5.56, but not shoot 5.56 in a .223. Unlike the 7.62 where depending on the vintage/headspace you can get in trouble shooting commerical .308. I should have been more clear in my post.

No that's cool , I just got confused cause I thought you were saying what I said was backwards, and I thought I was going

So...Who's on first?

[DavidCBaker]

Shot 20 of the rounds today, and the only thing that got blown up was some bright orange clays, so that was a relief.