What is the difference between Federal Premium .308 GMM with 175 gr. SMK and the Federal Premium 7.62.51 mm with the 175 gr. SMK loads?
Thanks
Thanks
-
Having trouble using the site?
Contact support
Difference between .308GMM & 7.62X51 w/175 SMK
- Thread starter Jerry m
- Start date
I'm no ballistician, but I'll share what I've read. In the similar guideline of "you can shoot .223 out of a 5.56 chamber but not the other way around" I read that you *can* shoot 7.62 out of a 308 chamber but not the other way around, meaning 308 is run to higher pressures? I had a box of each about ten years ago, shot them through both an AR10 and 308 Savage. Similar results. I didn't have a chrono then but the group sizes were very similar from each rifle.
Standby and someone will be along shortly to disagree with completely different experiences.
Standby and someone will be along shortly to disagree with completely different experiences.
The only difference is packaging, and . . . marketing.
I've fired both and saw no difference.
Unfortunately, due to the way that the marketing folks at Federal behave... You would have to get down to the specifics on the package.
At present, they offer the 175 SMK version, as well as their own 175 grain bullets. I think they have one that is a hunting oriented version called Terminal Ascent, and another that is like a close copy of the SMK.
The reason you would have to be more specific with how your packages are marked, is that in the past you could be talking about different versions that are no longer commercially marketed.
The GM762M2 has a military case. I have some of that brass and it is better than the regular GM brass. It has a hard case head and holds up better.
If its loaded on Lake City brass, yes. Top end of the load chart Ive found I need to pull 2gr out vs any other brass. So if 45 is the max on commercial brass, the max on LC is 43. Not a hard and fast rule, but pretty close.
The rest is all loaded on commercial brass which varies slightly in capacity, but not to the degree LC brass does.
The only difference is packaging, and . . . marketing.
I've fired both and saw no difference.
^ Same here...as long as we're talking the Federal stuff.
The .308 had the standard FC marked brass, and the 7.62x51 had the FC plus the year ('14). Both shot the same however.
Found this on Target Sports USA.
"I contacted FEDERAL with these same questions I'm seeing here. their response was. GM308M2 175gr is loaded to SAAMI specs. GM762M2 and M118LR are identical loads to military specs. They also said that usually the GM762M2 was slightly more accurate." - RICK (06/09/2017)
What is interesting is that FGMM 308 175 was found to be about 41.8 gn of IMR 4064 and M118 Mk 316 Mod 0 was listed as 41.745 gn of IMR 4064 with a Federal case and FGMM primer. This was back in the 2009-2014 time frame. Federal had a contract to produce the M118 Mk 316 Mod 0 Special Long Range after it developed the Round for NAVSEA Crane after issues showed up with M118 LR in Afganistan (the RL-15 issue).
The general consensus in that timeframe was that the rounds were the same but the case markings were required to be different. Whether the cases were actually different no one was certain at the time.
"I contacted FEDERAL with these same questions I'm seeing here. their response was. GM308M2 175gr is loaded to SAAMI specs. GM762M2 and M118LR are identical loads to military specs. They also said that usually the GM762M2 was slightly more accurate." - RICK (06/09/2017)
What is interesting is that FGMM 308 175 was found to be about 41.8 gn of IMR 4064 and M118 Mk 316 Mod 0 was listed as 41.745 gn of IMR 4064 with a Federal case and FGMM primer. This was back in the 2009-2014 time frame. Federal had a contract to produce the M118 Mk 316 Mod 0 Special Long Range after it developed the Round for NAVSEA Crane after issues showed up with M118 LR in Afganistan (the RL-15 issue).
The general consensus in that timeframe was that the rounds were the same but the case markings were required to be different. Whether the cases were actually different no one was certain at the time.
What is loaded in military 7.62 M118LR
I have a bunch of LC10 M118LR ammunition and it shoots fantastic. Does anyone know the powder/charge used in 2010 Lake City M118LR? Thanks
www.snipershide.com
M118LR is different from MK316 (GM762) which is different from FGMM 308 commercial ammo. Three different cases, three different powders, and two different primers. Same 175gr Sierra matching bullet.
The primers are crimped in Federal’s 7.62x51 FGMM load and the brass isn’t polished. You’ll have to take care of the crimp before seating a new primer if you handload. I never had to adjust my zero between the two FGMM175gr loads and I don’t remember my dope changing either.
M118 Long Range is prior to M118 Mk 316 Mod 0 Special Long Range. When the FGMM box changed from the orange box to the current design the powder in FGMM changed. The new load seemed to be about 40 gn of what may have been AR-Comp.
snipercentral.com
History of the M118 Ammunition
In the late 1950’s the United States military adopted the M14 battle rifle and M60 machine gun as standard combat arms incorporating the 7.62x51mm NATO cartridge which was the newly adopted NATO ro…
snipercentral.com
These days, it's AR-Comp for the 168 and 175 SMK Premium packages . . . according to recent sources from within Federal.
Last edited:
It averaged 40.7 grs and made 2700 FPS and that charge weight shoots awesome in my 175gr loads. I love the powder.
Back in March of last year I took apart 10 cases from a box of Fed Premium Gold Medal to inspect and take some measurements and compare with the other 10 cases from the box. Average powder weight for those 10 cases was 41.2 grs and the powder definitely looked like AR-Comp powder rather than the large log like IMR-4064. Out of my 26" Krieger barrel the average velocity for the 10 cases I took apart and uniformed the powder load was 2609 fps and the other 10 that were factory loaded averaged 2605; pretty close to the velocity of 2600 fps stated on the box.
I don't load the 175 SMK's much any more, though I still have several hundred sitting around, as I like the 169 SMK's much better. . . even when shooting out to 1000 yds, which I load with 41.1 grs AR-Comp to get 2700 fps. I even have some of the 177 SMK's that work real well with 40.8 grs of AR-Comp giving me a velocity at 2640 fps.
It's all good!
For those wondering still, this is what FGMM 7.62 looks like.
I've had this brass stored for a few years now after firing them 4 times and only just now measured their case head thickness. I found the FGMM 7.62 case heads averaged .202" in thickness and the Win. .308 cases measured .200"; not a lot of difference and well within variances one can find from one lot to another.
How do they compare to other brands? Well . . .here some case head thickness:
Lapua - .171"
Peterson - .185"
Starline - .210"
Alpha - .183"
When I weigh the cases, I can find no real discernable difference in weights. PS: all these cases have been uniformed, like. . . trimmed, primer pocket depth, neck turned, flash hole deburred.
Last edited:
Right after Sandy Hook, when consumables started trickling in - FGMM308 was also sold unpolished as such.
This was during that time when either PSA or Primary Arms had them on sale for $14 or $16 for a box.
I could be wrong in relation to M118 but most mil-spec's for cartridges for rifle require that visible evidence of mouth anneal be present. That would tend to mean that the cases are not cleaned after the annealing. I would guess that this might explain the differences in the FGMM cases. Just used overrun of mil-spec cases or selling M118 as FGMM!
That’s cuz when Federal was making M118LR they used a new type of case. Prior to that M118LR had a plain LC case without a primer crimp and a special LC LR head stamp.
Federal developed a new case where the head stamp read FC on top and the year on the bottom. Superb quality case. Completely different than commercial FGMM. These are not commercial cases with a military head stamp. They are hard at the base like lapua.
Federal developed a new case where the head stamp read FC on top and the year on the bottom. Superb quality case. Completely different than commercial FGMM. These are not commercial cases with a military head stamp. They are hard at the base like lapua.
The FGMM 7.62x51 brass kicked the crap out of the LC LR brass that I have (in regards to case capacity consistency). I couldn't get SD below 10 to save my life when I was reloading the LC stuff, and finally did an H2O capacity test. Bingo...there was where the issue laid.
I think I had an ES of .5gr H20 with the Federal stuff. It was around 1.5gr with the Lake City (same year '12 LR brass). This was done with a sample size of 20. I still have the results at the house, but the ballpark numbers here are pretty damn close.
I think I had an ES of .5gr H20 with the Federal stuff. It was around 1.5gr with the Lake City (same year '12 LR brass). This was done with a sample size of 20. I still have the results at the house, but the ballpark numbers here are pretty damn close.
