FGMM .308 vs 7.62

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kilo7788

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Feb 2, 2010
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#1
I searched for the answer but could not come up with anything conclusive. I have been hunting around for the cheapest FGMM 175s. I keep seeing the FGMM 7.62 like in the link below. What is the difference? I know the technical specs on both rounds respectively. On the federal site it does not differentiate between .308 and 7.62 but this link it does? On this site it is also a tad mroe expensive. Should it be as acurate as the .308? Am I to expect the lower Muzzle velocities from the lower pressure of the 7.62 load?

7.62 FGMM
 
#2
Re: FGMM .308 vs 7.62

http://www.6mmbr.com/308Win.html

.308 Win vs. 7.62x51--The Straight Scoop
Before we go much further, we want to address the oft-posed question "Are the .308 Winchester and 7.62x51 NATO one and the same?" The simple answer is no. There are differences in chamber specs and maximum pressures. The SAMMI/CIP maximum pressure for the .308 Win cartridge is 62,000 psi, while the 7.62x51 max is 50,000 psi. Also, the headspace is slightly different. The .308 Win "Go Gauge" is 1.630" vs. 1.635" for the 7.62x51. The .308's "No-Go" dimension is 1.634" vs. 1.6405" for a 7.62x51 "No Go" gauge. That said, it is normally fine to shoot quality 7.62x51 NATO ammo in a gun chambered for the .308 Winchester (though not all NATO ammo is identical). Clint McKee of Fulton Armory notes: "[N]obody makes 7.62mm (NATO) ammo that isn't to the .308 'headspace' dimension spec. So 7.62mm ammo fits nicely into .308 chambers, as a rule." You CAN encounter problems going the other way, however. A commercial .308 Win round can exceed the max rated pressure for the 7.62x51. So, you should avoid putting full-power .308 Win rounds into military surplus rifles that have been designed for 50,000 psi max. For more information on this interesting topic, read the following articles: Gun Zone's 30 Caliber FAQ; Cruffler.com Technical Trivia, June 2001; and last, but not least, Steve Redgwell's .308 vs 7.62x51 Analysis, which really provides a definitive explanation. Reloaders should also note that military ammo often is made with a thicker web. Consequently the case capacity of 7.62x51 brass is usually less than that of commercial .308 brass. You may need to reduce recommended .308 Winchester loads by as much as 2 full grains, if you reload with military 7.62x51 brass, such as Lake City or IMI.
 
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#5
Re: FGMM .308 vs 7.62

Ask Federal.
laugh.gif


It's FGMM: they packaged it the way they wanted to when they went from the white box to the red box. I have some that says .308, but it's of the 168gr SMK variety.

Am I missing something?

 
#13
Re: FGMM .308 vs 7.62

crimped primer, annealed brass that hasn't been polished, prob a true 50,000 psi max but i would like to know if they gauged off the 7.62 or .308 GO/NO Go for the chamber, of if they just used diff brass but kept to the .308 FGMM specs...
 
#14
Re: FGMM .308 vs 7.62

I'm so happy I found this thread. I had seen the 7.62 ammo on Palmetto's site, but had been leary to order it. Thanks to this thread, I've now got 80 rounds headed my way.
 
#15
Re: FGMM .308 vs 7.62

I was always told 7.62 ammo in a .308 rifle is a good to go, vise versa is a no go but, that mainly applies to older 7.62 rifles. Some newer 7.62 rifles should be able to handle the difference in ammo. I personally just would not put .308 ammo in a 7.62 rifle .
 
#16
Re: FGMM .308 vs 7.62

do the primers have the sealant stuff on them and is there sealant where the bullet is seated? Might be worth getting if it is truly milspec, be good addition for the long term storage SHTF.
 
#17
Re: FGMM .308 vs 7.62

Interesting to note here, GAP is now rolling all of their rifles 7.62 NATO instead of .308 WIN. I looked up the pressures of each, and I noticed the difference and got concerned. However, GAP reassured me that there is no difference between their rifles. Seems like it would make more sense to roll them .308 WIN, but eh oh well. I guess this is a good example of the difference not really making a difference.
 
#18
Re: FGMM .308 vs 7.62

Didn't want to bring up an old thread, but seems like this is the most recent and informational thread on this.

I have been trying to find more info on the FGMM 175 308 vs 7.62 and haven't got anything solid.

What I have found is the 7.62 might possibly have slower velocity which is slightly worse and the 7.62 has cimped primers.

So if I plan on reloading after a couple months and using the brass of the factory ammo then the 7.62 won't be a good choice right? It's much harder to reload brass that had crimped primers correct?

Oh and I got 3 boxes of the 175 7.62 from palmetto and agree that they look really dirty. There's no dents or anything, just not polished up like most commercial stuff. I have only tried them at 100 yards but they seemed to work just as well as the polished up 168's, so don't really care if the bras isn't polished.
 
#20
Re: FGMM .308 vs 7.62

I've shot 150 rounds through my 5R and a Chrono and it is dead on, I just ordered 500 more rounds. Only issue I've had is need the swage tool on the primer pocket when reloading for $19.95 a box it's hard to beat.
 
#21
Re: FGMM .308 vs 7.62

I agree the 7.62 FGMM is not as polished as the 308. I noticed that it left more residue on the exterior of my rifle than the 308 (green residue), but to be honest at 100yds they shot almost identical sub-MOA groups out of my Noveske N6 with the 7.62 being slightly tighter. YMMV.
 
#22
Re: FGMM .308 vs 7.62

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ss10ring</div><div class="ubbcode-body">I've shot 150 rounds through my 5R and a Chrono and it is dead on, I just ordered 500 more rounds. Only issue I've had is need the swage tool on the primer pocket when reloading for $19.95 a box it's hard to beat. </div></div>
So its something thats easy and fast to work around when reloading then?

$20 is hard to beat, but the 308 168's are 20 also in other places and I dont shoot 600+ yards often yet so 168's would do. Thats why I was asking the question.
 
#23
Re: FGMM .308 vs 7.62

To resurrect a thread, bottom line: is there a POI shift from FGMM .308 to FGMM 7.62? I'm not reloading it, just shooting it. I don't want to set up Atrag on the 7.62 load only to find out that .308 is going to have different downrange data.
 
#24
Re: FGMM .308 vs 7.62

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Aequitas 1/1</div><div class="ubbcode-body">To resurrect a thread, bottom line: is there a POI shift from FGMM .308 to FGMM 7.62? I'm not reloading it, just shooting it. I don't want to set up Atrag on the 7.62 load only to find out that .308 is going to have different downrange data. </div></div>

From what I've seen it really depends on the gun, My 700 5R with a 20" 1x10 loved them and was super consistent. Two friends tried them in 24" 1x11.25 700 5Rs and they shot like a shotgun pattern. Best bet is to test a few boxes and see what you barrel thinks of them
 
#25
Re: FGMM .308 vs 7.62

Excellent advice. In better circumstances I'd do exactly that. Problem is I'm overseas, have a new rifle (GPS Defense 18"bbl) being delivered to my FFL awaiting my arrival, and I'm taking the new rifle to a LR school the next week. I'm going to have basically enough time to put a 100yd zero on the rifle and head out. Was trying to get the ammo ordered and sent to the school ahead of time. GPS recommends the Black Hills 175gr. I hated to pass up the FGMM for such a ridiculously low price. I may just have to put all my eggs in an unknown basket and take my chances. Not the best of options, but I'm short on others.
 
#26
Searching google and want to bring this thread back life. I understand the differences between the 7.62 and 308 chambering but looking for an answer to the question that seems to get danced around in this thread. What is the velocity difference between the two FGMM 175 Sierra loads of 308 and 7.62? Would love to hear chrono results between the two different flavors in the same rifle.
 
#27
I always assumed the FGMM .308 was for Bolt Guns and FGMM 7.62X51 was for Gas Guns. Using that logic both can be used in a Bolt Gun but only the FGMM 7.62X51 should be used in Gas Guns as the FGMM .308 may be too harsh on the gas system. But it could also be a marketing ploy to use FGMM .308 reject lots as FGMM 7.62X51 as its usually cheaper.
 
#29
I might be wrong( happened once), but I believe the chamber pressure for 7.62 is in CUP, not psi. It's actually higher than .308, but I don't remember the number off the top of my head, but possibly somewhere near 65,000 psi. Don't quote me on it though, do your own research.
 
#30
I'm not referring specifically to FGMM- but to .308 & 7.62 in general.

I understand that .308 is the higher pressure round in terms of SAAMI, but the 7.62 round was not really designed or meant for the .308 chamber.

My experience has been that expanded 7.62 brass will expand more than "normal for .308" in the .308 chamber. Will it shoot? Most likely.

But the walls of the 7.62 are slightly thicker and often have harder primers which may contribute to problems with ejection and reliability. I believe it would not be out of the question that one might inevitably get a case stuck to some degree.

I would NEVER recommend running 7.62 in a .308 bolt gun. Just my opinion and experience.

Your gun, your choice.

----

Although military ammunition works well in sporting rifles, using sporting ammunition in military rifles is usually not recommended. 7.62 NATO ammunition is loaded to a maximum average pressure of 50,000psi and proof tested at 67,000psi. For reliable feeding in the field, military 7.62 NATO rifles have over sized chambers and military brass is made thick to allow expansion to the chamber walls without cases splitting. Sporting .308 ammunition is made to the same sized outside dimensions as 7.62 NATO ammunition but lacks the thickness of brass to flow and fill a loose military chamber with the possibility of split or ruptured cases as a result. Commercial hunting ammunition can be loaded up to 62,000psi. Incidents of sporting ammunition rupturing in military rifles are rare, considering commercial ammunition is not usually loaded to high pressures, but incidents have been recorded.

from:
 
#31
Here's the difference between the federal 175 gold medal match and the 7.62x51

We all know about FGMM 168 and 175 in 308, no description required

The 7.62x51 is an over-run from the SOCOM MK316 contract. It is loaded with the same brass as the FGMM but it does not undergo a tumbling process to make the brass shiny. It is also loaded with a different powder as per the SOCOM specs to achieve a certain MV and temperature sensitivity. It's faster and shoots better in my opinion than the 175FGMM

The contracts require a certain percentage of over-runs so the agency can reject a certain percentage of Ammo. The over-runs, in this case, are offered to the civilian market repackaged as FGMM 7.62x51. This ammo is outstanding and you should buy it whenever possible
 
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#32
This is interesting. In my testing in my Sr25 I found the 7.62 loading to shoot significantly better than the 308 loading. Hearing that it was a match loading essentially for the m110 program, it makes sense that it runs more accurate in my ECC.
 
#33
The 7.62x51 FGMM isn’t as shiny and the primer is crimped. Both 7.62x51 FGMM 175gr and the .308 FGMM 175gr shot interchangeably in my rifle. Same zero same dope. If you want to reload the 7.62x51 brass you have an additional step in the process.
 
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