FGGM 308 load

I doubt all lots of Federal Gold Medal Match 308 ammo has the same charge weight. They probably load to velocity specs and if it's within pressure specs, they do that for the powder lot used. I've shot a few different lots of it as well as Remington and Hornady match ammo; each lot's charge weight for a make was different. To me, that says they're loading for velocity and pressure specs just like arsenals did loading 7.62 NATO M118 and M852 match ammo.

Across several barrels, I've seen no significant accuracy difference in a 3 grain spread of IMR4064 under Sierra 168's through 41 to 44 grains through 300 yards in range. That's what I've observed shooting at least 20 shots per test. Of course, if one shoots 3 or 5 shots per test group, their size can have a 3x or more spread across them and their centers are not at the same place relative to aiming point. The first group is not always the smallest; or largest, for that matter.

One reason a rifle shoots new FGMM ammo best compared to reloads with its fired cases is the bolt face is not square with the chamber axis. Case heads are out of square from first firing and they smack the bolt face at different points around it when fired causing more barrel whip in that direction. That can add a half MOA or more to group sizes. Military teams learned that back in the '60s with their 7,62 NATO match conditioned service rifles. Their bolt faces were never squared up and test groups strung from 7 to 1 o'clock right angles from the bolt lug axis when in battery. Bolt action rifles tend to string shots horizontally from this issue as their lugs are at 12 and 6 o'clock when fired.

tcoz said:

The load I'm shooting out of my 308 Savage 10 FCP is 42.2gr IMR-4064 with 168gr Hornady HPBT Match bullets. Accuracy (precision) is acceptable at MOA to slightly sub-MOA but since I'm still getting accustomed to the rifle, it might be on me. I shot a box and a half of FGGM loaded with 168gr SMKs and been consistently closer to 0.5-0.75 MOA so I'd like to see if I can duplicate that load with the same results.
I've read in a few different places that 42.8gr of 4064 is the FGGM load so I'm asking whether anybody here can verify that. I have a box of 168 SMKs to use.
I've already tested my rifle up to 43.5gr with absolutely no pressure signs so I'm not planning to work it up again. I'd just like to get some confirmation of the FGGM load.
Thanks guys.

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I've heard Federal has switched to RL-15 for their FGMM .308 load.

Reloader 15's in the same speed range as Varget to IMR4064.

I think one will be hard pressed to tell the difference between all three; if they test properly to have at least 95% statistical significance for each.

Bart B. said:

Reloader 15's in the same speed range as Varget to IMR4064.

I think one will be hard pressed to tell the difference between all three; if they test properly to have at least 95% statistical significance for each.

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I shoot a 30-06. Bullets range 150gr. to 168gr IMR4064 works the best for me. I just go for hunting accuracy out to 200-250 yds.

168 amax is good and less $.

popper said:

168 amax is good and less $.

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I like to shoot GMAX.

My thoughts are that if you load with a Sierra 168 SMK to 1.80in OAL, Federal brass and primers, and use enough powder to get to 2600 ft/sec velocity at 10 feet away from the barrel that you are spot on for matching the FG parameters. At least that is my experience.

My thoughts are that this is a perfect example of why you need a chronograph, your loads are so close to the max recommended pressures that you should monitor velocity so that you have some idea of what your pressures are.

Since you are using a Hornady bullet you should use the Hornady reloading manual and their newest manual (the 10th edition) doesn't list IMR 4064 for the .308 / 168gr combination, most likely because they felt that better powders exist for this application. Since they don't provide any powder charge recommendations I used my QuickLoad software to see what kind of internal ballistics you might have and even though I don't have enough specifics to really make a good estimate about your load I can say that you are so close to being over the SAAMI max pressure that I'd be careful. I'd also suggest that your process of estimating over pressure isn't very accurate, in fact, I don't believe that very many people really know how to read over pressure by looking at primers or cases, that's why I'd recommend using a chronograph. Muzzle velocities are directly related to pressure so a specific powder will produce very consistent velocities in specific barrels, that's a far more reliable way to estimate when your pressures are getting too high. Don't forget, a hot load developed when ambient temperatures are low will probably be quite a bit hotter when the ambient temperatures are much higher.

I understand, it sucks when stupid people make stupid rules to stop other stupid people from doing stupid things.

I used to work at a gun range and I've actually seen people walk forward of the firing line while it was still hot - it's amazing how some people have lived as long as they have.

If you look at the Hodgdon online reloading data you'll notice that they show powder charge recommendations for both the Barnes 168gr TTSX and the Sierra 168gr HPBT, notice that they have different max powder charges, this is because of differences in the dimensions and materials of the bullet. This is why I recommend using the reloading manual of the company that produced your bullet, differences in the bullets (even of the same weight) will produce differences in the pressures. A lot of people complain that Hornady produces lighter loads, that's because most of Hornady's bullets are shaped in such a way that they produce higher pressures. Usually you'll find that a Hornady bullet has more of it inside the case when it's seated to the same cartridge length as another brand of bullet. Quite often Hornady bullets have longer shanks (the straight area along the bullet's profile that is full diameter) and that increases the friction between the bullet and whatever it contacts.

Then there are differences in case volume that will have an effect on the pressure. I've seen a lot of people claim that volume doesn't make much difference but that all depends upon the kind of shooting you're doing. If you want very hot, long range loads that are built for accuracy then it's very important to be aware of case volume, on the other hand, if you're just a plinker that likes to blast away at cans from time to time then who cares, build a nice middle of the road load that works reliably and you'll be happy.

Also the chamber of the rifle will have an effect on the pressure, that's the hard part with QuickLoad, it can't predict the chamber dimensions and you will always have some variation between the real world and what the software predicts. I have a new 30-06 that I'm starting to work with and I always get 50 to 100 fps of error in my load predictions, I haven't figured out if it's the powder or the rifle's chamber but something is giving me higher pressure. I can adjust QuickLoad to match up with the real world chronograph numbers but it's a surprise when I can usually get predictions that are within a 25 fps for my semi-auto rifles. That's why I was careful to not say what your pressures were, I don't know how far off QuickLoad is, if your velocities are 100 fps slower than it is predicting then you might have a top end load but not exceed the SAAMI max, on the other hand you could have a load that is 100 fps faster and then you'd have pressures that were dangerously high.

I don't trust reading the primer, it works when you are really experienced with your rifle and know what to expect because you've compared what you see to pressure and velocity info that was verified but when you are simply comparing what you see to pictures that others have shown then I'd be cautious. Bolts and firing pins are different and they will create different impressions on the brass, extrusions on the brass around the firing pin indent can be created by a firing pin hole that is too large but it can also be mistaken for extrusion due to a hot load.

Quick load's rep told me their software calculates a guess or average for its output numbers. No adjustments for different powder and primer lots, bullet diameter shape & jacket details, no variables for chamber, bore and groove dimensions as well al how the barreled action is held when fired. Users should take calculated data to compare loads for general information. Never ever the exact numbers you and your stuff does with a given load.

"...like to see if I can duplicate that load..." No, you don't. You want to use the SMK's instead of the Hornady Match bullets with IMR4064 and work up the load for your rifle. You cannot get the same lot or even close to the same lot of powder Federal used anyway.
"...most likely because they felt that better powders exist..." More likely some MBA got mad at another MBA. Or they decided there was enough IMR4064 data and just didn't bother testing it again.
"...the Barnes 168gr TTSX..." Is a solid copper hunting bullet. Not a match bullet. An A-Max, a Hornady Match bullet and an SMK are not hunting bullets. Unless you're hunting varmints. Even Barnes' site data(all of which is about the bullet weight and nothing else.) is different than Hodgdon's. Perfectly normal anyway. Manuals are just like that.
"...using a Hornady bullet you should use the Hornady reloading manual..." Nope. Who made the bullet makes absolutely no difference at all.
"...I trust QuickLoad..." That's like trusting a programmer not to blame the hardware for his mistakes.

Sunray said:

You cannot get the same lot or even close to the same lot of powder Federal used anyway.

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Did you get that info from Federal?

Last time I talked with a Federal rep, he said they use regular commercial powders reloaders use. That way, their load data is easy to use by customers. Their actual charge weights in their match ammo may vary a grain or more because they load for velocity and pressure specs. Accuracy changes are insignificant across different lot charge weights .

I've weighed charge weights of four makes and different lots of 308 Win match ammo. Almost a two grain spread in charge weights. Accuracy equal across all.

Sierra does not work up new loads each time a new lot of components are used. Nor for a new test barrel.

Bart B. said:

One reason a rifle shoots new FGMM ammo best compared to reloads with its fired cases is the bolt face is not square with the chamber axis. Case heads are out of square from first firing and they smack the bolt face at different points around it when fired causing more barrel whip in that direction. That can add a half MOA or more to group sizes. Military teams learned that back in the '60s with their 7,62 NATO match conditioned service rifles. Their bolt faces were never squared up and test groups strung from 7 to 1 o'clock right angles from the bolt lug axis when in battery. Bolt action rifles tend to string shots horizontally from this issue as their lugs are at 12 and 6 o'clock when fired.

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Bart, I just wanted to say that I thoroughly appreciate your contributions to this forum. Posts like this are pure gold; something I'd never learn on my own.

This posts touches on something that's been bugging me for a while. What role does new brass play in accurate reloads? My focus is largely pistol, and I've noticed that factory match ammo shoots better than reloads. I've read the military pistol teams use brand new starline brass (again, for pistol) that's hand trimmed to length. They'll reload it one time, for short line use, then discard.

With respect to rifle brass, is it possible or worthwhile to resquare the case heads? Also, are modern rifles, with tighter manufacturing tolerances, better with respect to square bolt faces vs bore?

Thanks.

I'm not familiar with Savage floating bolt heads: this might help:

http://www.savagearms.com/firearms/model/12FCLASS/

Click on the floating bolt head then watch the video. It doesn't show the case head to bolt face details.

Call them then ask them about it.

John C said:

What role does new brass play in accurate reloads?

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Not much except if accuracy is better with new cases compared to your reloads with them, either your reloading tools and/or their use ain't too good, or the rifle bolt face is cockeyed and not square with the chamber axis.

Just stuffing a proven suite of primer, powder and bullets in new cases, that has always produced ammo that shot virtually equal to what reloading those fired cases do.

The only thing the floating bolt head in a savage does is ensure both recoil lugs make full contact with the receiver. It's still possible for the bolt face to be out of square with the chamber. The nice thing is you can order new bolt heads and change barrels to go from a 223 to a 22-250 or a 308 or a 6mmbr or whatever with no gunsmithing