Spanish Mauser FR-8 (7.62 Nato or 308 Win)

[ORHunter79]

Hello,

I have a Spanish Mauser F8 that is stamped 7.62 Nato. From what I read online, some say it's ok to shoot .308 win through it, some say it's not.

I thought about selling this thing, cause I bought this to use as a handy truck gun for hunting and finding 7.62 Nato SP is hard.

I have to admit I have tried .308 win through it using Tulammo which run at 42,700 psi. Here is a link:http://tulammousa.com/products/centerfire-rifle-cartridges/308-win-fmj/

The primers bulge back a little after firing it. So I'm not sure if I want to try full power .308 loads.

What are your thoughts?

 

[morcey2]

FR-8's are built on Spanish M43 large ring mauser receivers, which are incredibly strong. They're chambered in 7.62 NATO, but they should safely shoot 308 Win. The caveat is that the 7.62 chamber is slightly larger than the 308 Winchester and if you reload, the 308 brass won't last very long at all. If it headspace is like other FR-8's I've seen, it'll close on the 308 No-Go gage, but not the field and won't close on the 7.62 No-Go.

If the headspace is excessive, you can have the primer back out. BUT it can also happen if chamber pressure is too low to force the cartridge base back to the bolt face. I have that problem with domestic 8mm mauser loads in all of my 8x57 rifles. If the Tulammo really runs at 42700 psi, that's probably the problem.

If it were mine, I wouldn't hesitate to shoot both in them. And that's coming from someone who's been described as 'paranoid' on the safe side of issues like this.

BTW, nice gun. I need to get one.

Matt

 

[303tom]

You tell me what the difference is ?

 

[R.W.Dale]

Just to add to the information above A no-good gauge would fit in in my fr8 with very slight drag on closing .


Fireformed and then neck sized brass lasted just fine
posted via tapatalk using android.

 

[W L Johnson]

I have a Spanish Mauser F8 that is stamped 7.62 Nato. From what I read online, some say it's ok to shoot .308 win through it, some say it's not.

That's mostly come about because a lot of people believe that 308 is higher pressure than 7.62x51 (7.62 NATO), it's not. You'll keep seeing 7.62x51 quoted as being 50,000 PSI vs 62,000 for 308. Right numbers, wrong units of pressure, 7.62x51 is 50,000 CUP (copper units of pressure) not PSI. This came about because they were tested using two difference methods. People not knowing what CUP is, or not noticing or not even caring, keep changing CUP to PSI without converting the numbers. It's very much the same thing as when people confuse inches with centimeters.

They are in fact virtually the same pressure when using the same units of pressure. Even if their was a big difference, 7.62 NATO chambers are proofed (per NATO Docs) to 75,000 PSI, but bear in mind that doesn't mean yours, being and older mil-surplus, is.

There is however a head space different that you have to watch out for. It's usually not an issue on most rifles but if your head space is borderline one way or the other it becomes one. And as the others before have pointed out, gauges go a long way in helping. But it doesn't hurt to have a gunsmith check the headspace.

 

[Trent]

Morcey is on the money.

My personal experience with shooting 7.62x51 military surplus in bolt guns is 7.62 tends stick in chambers reamed for commercial 308. Surplus 7.62 ammo I've tried would seize the bolt right up. Never had a commercial 308 load do that to my 308 bolt guns. This makes since - although the OD is the same, a full power 7.62 NATO surplus is designed to be shot in machinegun and full auto chambers which are typically larger / looser than 308. Full power 7.62 seizing up a bolt gun chambered for 308 is pretty common, in my experience.

Over the years I've learned to feed the 7.62 surplus in to my G3 or CETME, and use commercial 308 or hand loads for the bolt guns.

This being said I have no experience whatsoever with that pretty rifle you have shown above. I have a 1933 Spanish Mauser, but it's in it's original 7x57mm config.

Mauser receivers were forged from the stuff of legend and myth. Just kidding on that - however, they ARE built very strong.

Yes, your casings MAY fire form a bit larger in a 7.62 NATO chamber (it all depends on the reamer the outfitter used when making it.) HOWEVER if you neck size for reloads, this should NOT be an issue, as you only "stretch" the brass once, and it's not a really BIG stretch (as long as your headspace is good).

Keep 308 brass shot in it separate from any other 308 rifle brass you may be collecting, neck size, and you should be good to go for a long, long time.

 

[303tom]

I shoot reg. .308 hunting rounds in mine. I actually trust Factory .308 in my FR-8 more than I do in my 2A & 2A1`s & I use them in those.

 

[ORHunter79]

Thanks for all the advice. I'm going to go out here in the next few days and try some SP Winchester ammo. I really love this little rifle and hope it'll make a good hunting rifle. I'll post results whether it be nothing happened, backed out primers or me loosing my face......I'll post that after I get better of course....Thanks all.

 

[jonnyc]

As all have correctly pointed out, the "two" rounds are one-in-the-same, just really a difference between military and commercial chambers. I have found Tula and Wolf 7.62/.308 to be pretty hot, and I stopped using it in my 2A1.

 

[NCsmitty]

If your FR-8 passes the headspace gauge check, it will be fine with any ammo, be it milspec or commercial 308.

It's the FR-7 small ring Mauser in 7.62 that's questionable with commercial 308 ammo because it's a pre-98 action.



NCsmitty

 

[paintballdude902]

never had a problem firing .308 in mine

 

[35 Whelen]

This is a good thread. I honestly expected alot of the same ol' internet myths of the 308 Win being loaded to higher pressures than the 7.62x51. Incidently, (and if some of you have already seen this, bear with me) here: 7.62 NATO Pressure vs. commercial 308 Winchester is a fantastic post over this very subject. It's seven pages long, but the author has some good credentials and infallible information.

35W

 

[ORHunter79]

This is a good thread. I honestly expected alot of the same ol' internet myths of the 308 Win being loaded to higher pressures than the 7.62x51. Incidently, (and if some of you have already seen this, bear with me) here: 7.62 NATO Pressure vs. commercial 308 Winchester is a fantastic post over this very subject. It's seven pages long, but the author has some good credentials and infallible information.

35W

Great Article. Thanks.

 

[303tom]

There ain`t a nickels worth of difference between the .308 Win. & the 7.62 NATO ............

 

[desidog]

As the date on your receiver will indicate, your rifle was made before NATO and its standardized ammo existed. The FR-8 was chambered for 7.62 Cetme. Pressure should be fine with .308win, but as others have mentioned, with popping primers you should check the headspace.