Ruger SFAR 308 / 7.62 NATO Ammo

[Bedfordtec]

I recently bought one of the new Ruger Short Frame Auto Rifles (SFAR) in 308. Finally got my Primary Arms 1X6 Scope and Aero Precision mount. Going to test fire and sight in this week. I have a bunch of Cold War battle rifles like the M1A1, FN-FAL, CETME, BRN-10, and G-91. However, I am a bit leery of shooting FMJ 7.62 NATO rounds through it. About 40+ years ago I bought my first deer rifle… a beautiful Browning BLR in 308. I was a USMC 2nd LT and asked the store owner if I could/should use military 7.62 NATO ammo in it as it was common ammo. I knew it would chamber. The gentleman said that the military ammo was too hot for it… not that it would burst the chamber/barrel but would cause excessive wear. He said commercial ammo was better. Don’t remember the weight but I bought two boxes of Winchester soft point hunting rounds and I believe I have half a box left in my ammo Locke. It was right on at 100 yards with open sights so I was happy. Only deer hunted a couple of times and no kills. Anyway, is FMJ 7.62 NATO ammo ok to use in the Ruger SFAR or is commercial ammo better. I have US, South African and Portuguese and a few other types in battle packs. Thanks for your help.

 

[Pat Riot]

According to the Ruger website the SFAR is built for .308 and 7.62 NATO

https://ruger.com/products/sfar/models.html

 

[LoonWulf]

AFAIK .308s spec is 2K psi or so higher than the 7.62s spec....Considering that the BLR,BAR, and BPR were chambered for 300WM and 7MM both of which spec 60K+ and ALSO generate significantly more bolt thrust, I'm inclined to say your source was probably running on bad/out of date info.
Might have just been the "levers arnt as strong as other action types" theory etc.

 

[adcoch1]

AFAIK .308s spec is 2K psi or so higher than the 7.62s spec....Considering that the BLR,BAR, and BPR were chambered for 300WM and 7MM both of which spec 60K+ and ALSO generate significantly more bolt thrust, I'm inclined to say your source was probably running on bad/out of date info.
Might have just been the "levers arnt as strong as other action types" theory etc.

Beat me to it, the 308 has a slightly higher pressure spec, and most x51 NATO loads aren't full pressure, just up to velocity specs anyway.

 

[Havok7416]

7.62 NATO as already stated, is effectively a slightly watered-down version of .308 Win. Even then, I'm not getting excited over a 2k difference in pressure (in favor of the .308). By the time you wear something out with that pressure difference you will have put ungodly amounts of ammo through the weapon.

 

[lysanderxiii]

Where, exactly are you people getting the idea that ammunition loaded to military specifications is "watered-down," "weaker," or lower pressure? The SAAMI pressures are measured by transducer at mid-case, the military pressures are measured at the case mouth. The values are different because the pressure measurement location is different.

 

[powermad]

Most don't know that the pressures measured are not the same as well.
CUP and PSI are not the same and can't be converted.

IIRC in 1985 HP labs conducted a test using the same pressure test for 7.62 NATO and .308
7.62 was slightly less.

If you have a 7.62 NATO chambered rifle like a FAL then .308 may have a problem if the headspace is out of SAMMI specs.
When I built one I set the headspace for SAMMI minimum and shot everything through it.

 

[Pat Riot]

7.62 x 51 NATO max pressure
https://en.m.wikipedia.org/wiki/7.62×51mm_NATO

.308 Winchester max pressure
https://en.m.wikipedia.org/wiki/.308_Winchester

7.62 is 2000 PSI less than .308.

I find it fascinatingly stupid how hard it is to find accurate info on cartridge pressures between the .308 Winchester and 7.62 x 51.

 

[mshootnit]

I would get some Hornady Black 168 gr. 308 to run through it. Good shooting reasonable priced load. Designed for MSRs.

 

[Bcwitt]

Not every salesman knows what they are talking about. I wouldnt doubt he was just pointing to a more profitable item for him.

 

[Demi-human]

Back in the day…
When Garands were more widely used, there was a common knowledge that the pressure burn rate of the power was a serious issue. Too slow a burning powder could put too much pressure to the op-rod, bend it, and cause the rifle to cease functioning.
Many humans equate this to the hunting ammo being more powerful or “hotter”.
Nope. Just a different burn rate.
That this mythology continues, and even threads itself into other areas, like handloading, rather than being educated out, is an astounding event. I suppose “Don’t” travels better than the luggage of knowledge.

That we had a similar coincidental “teething” issue with the M-16 is sadly, not comical.

The SAMMI difference, like the measurement process, is a non-starter for me. That is the pressure difference between magnum and standard rifle primers. Just doesn’t interest me when it comes to general rifle operations.

Way back then, as now, I suspect @Bcwitt has a very compelling reason. As well, I’m glad they shot well, even if you haven’t gotten anything, yet.

As for the Ruger, find the best ammunition, whose price you can stomach, and use it without worry. It’s built for it. I agree the Hornady Black is very good for the price.


May we request an update to this thread with a range report of the Ruger?
I’m interested!

 

[Bcwitt]

Back in the day…
When Garands were more widely used, there was a common knowledge that the pressure burn rate of the power was a serious issue. Too slow a burning powder could put too much pressure to the op-rod, bend it, and cause the rifle to cease functioning.
Many humans equate this to the hunting ammo being more powerful or “hotter”.
Nope. Just a different burn rate.
That this mythology continues, and even threads itself into other areas, like handloading, rather than being educated out, is an astounding event. I suppose “Don’t” travels better than the luggage of knowledge.

That we had a similar coincidental “teething” issue with the M-16 is sadly, not comical.

The SAMMI difference, like the measurement process, is a non-starter for me. That is the pressure difference between magnum and standard rifle primers. Just doesn’t interest me when it comes to general rifle operations.

Way back then, as now, I suspect @Bcwitt has a very compelling reason. As well, I’m glad they shot well, even if you haven’t gotten anything, yet.

As for the Ruger, find the best ammunition, whose price you can stomach, and use it without worry. It’s built for it. I agree the Hornady Black is very good for the price.


May we request an update to this thread with a range report of the Ruger?
I’m interested!

I was just trying to make the
Point that you need to do your research before you buy.

 

[A526051]

Here's my target from yesterday. Ruger SFAR 16" Primary Arms SLK Raptor Hornady 168 Black. I think I'll get some

 

[mshootnit]

wow good shooting.

 

[bfoosh006]

I'd suggest buying quality 308 / 7.62x51... surplus included, and research it first.

For instance, ZSR 308 Lot 15 is now responsible for 4 separate kabooms.

 

[Bcwitt]

I'd suggest buying quality 308 / 7.62x51... surplus included, and research it first.

For instance, ZSR 308 Lot 15 is now responsible for 4 separate kabooms.

Well thats good to know. Thanks. Any other lots to be weary of?

 

[bfoosh006]

Well thats good to know. Thanks. Any other lots to be weary of?

As far as I have read... Just Lot 15.