Sleuthing the Federal Gold Medal match load... Mk 316 Mod 0?

[Rprecision]

Rprecision, what rifle are you using? That load should be on the mild side... could it be the brass just needs to be FL sized fully? What about Federal factory GMM, does it show any pressure signs when you shoot it (or have you tried it yet)?

Its a AI AE MKIII running a AINA 1/10 Bartlien 5r, 18.5" Barrel, TBAC 30-P1.

These cases are full length sized, Trimmed to 2.000" shoulder bumped back .003-004" with a Forester FL Match Die. They don't have any problems going in......

Of the 60 Rounds of 175 FGGM I have, I have shot 10, which shot very well 1/4 MOA, with zero pressure signs.

I was going through the brass shot above and one of the WLR loads has a ejector swipe.

In other load development the gun usually shows pressure signs before published or known max data, just never seen it .2 grains over start (41.5 Published)

I'm all ears if you got suggestions, I know FC brass is not great, I just happen to have a pile of it.

 

[Twoboxer]

Have you by chance compared the water capacity of a disassembled FGMM case vs your reload case(s) (after resizing)? Yours should be larger, which wouldn't help finding the cause . . . but I'm having trouble accepting the primer as the sole reason.

 

[poink]

It smells scientific, it has a scientific talk, but it doesn't have the scientific walk. Smell, look and weight doesn't mean its the same powder. You need a mass spectrometer to be sure. You also need a better scale to get an accurate reading. The one you are using can vary a few tenths by means of simple air current. And using a powder measurer is the least reassuring thing about this video. You could be totally right, it could be the same exact load. But your method is severely flawed.

 

[JMGlasgow]

Tag for later.

Anyone try the match-burners instead of SMK?

 

[doctordoctor]

It smells scientific, it has a scientific talk, but it doesn't have the scientific walk. Smell, look and weight doesn't mean its the same powder. You need a mass spectrometer to be sure. You also need a better scale to get an accurate reading. The one you are using can vary a few tenths by means of simple air current. And using a powder measurer is the least reassuring thing about this video. You could be totally right, it could be the same exact load. But your method is severely flawed.

I bet mass production uses scientific methods to load ammo

 

[Dan Newberry]

Having a more precise scale wouldn't necessarily help us prove that FGMM is the Mk316 load, since the powder lot variations might necessitate slight changes in charges weights from one lot of ammo to another.

On the ejector swipe and pressure signs on the reloaded brass, it could simply be that the brass has endured through one firing (the factory load), and cannot stretch and flex back a second time to a sufficient degree to prevent case trapping and ejector swipe. With virgin brass, we can get away with more pressure, but on subsequent firings the case spring-back may not be good enough to work with that same pressure level again.

The next node down from the 41.7 grain load would be at 40.5 grains. I would guess you'd see 2450 fps or so in that area, or maybe even a little more since you have a faster barrel with a tight chamber.

Dan

 

[918v]

+1

I have two lots of 4064, one needs .5grs less powder to reach the ideal velocity.

 

[Rprecision]

Having a more precise scale wouldn't necessarily help us prove that FGMM is the Mk316 load, since the powder lot variations might necessitate slight changes in charges weights from one lot of ammo to another.

On the ejector swipe and pressure signs on the reloaded brass, it could simply be that the brass has endured through one firing (the factory load), and cannot stretch and flex back a second time to a sufficient degree to prevent case trapping and ejector swipe. With virgin brass, we can get away with more pressure, but on subsequent firings the case spring-back may not be good enough to work with that same pressure level again.

The next node down from the 41.7 grain load would be at 40.5 grains. I would guess you'd see 2450 fps or so in that area, or maybe even a little more since you have a faster barrel with a tight chamber.

Dan

Thank you for the information.

+1

I have two lots of 4064, one needs .5grs less powder to reach the ideal velocity.

Something I have considered, you may have a good point ! I am going to try a few loads below around 40.5 up to 41.0

 

[JMGlasgow]

I did an OCW test with the FGMM as a test base. I started at 41.3 of IMR4064 and ended at 42.5 in .2gr increments. Settled in 41.7 with a node range in between 41.5 and 41.9. This was using FC brass and CCI 200 primers. Loaded to 2.85 COAL. Shot some of the best groups I've ever shot with this load. Chronographed at 2670 avg out of my 24" Savage barrel that has over 3000 rounds down it. These were tested with the Barnes match burner 175 bullets.

I also tested using RL15. I also modeled that around the M118LR. My rifle really liked the clone load also. Settled on 43.1 of RL15. Same COAL, brass, and primer as above. I have not Chronographed this load yet though.

 

[Rprecision]

Rprecision, what rifle are you using? That load should be on the mild side... could it be the brass just needs to be FL sized fully? What about Federal factory GMM, does it show any pressure signs when you shoot it (or have you tried it yet)?

Here are my final results from duplicating this load.

A few things came up since my original post. (1) Sticky extraction was isolated to a sizing problem. the standard Forester NM Sizing die was not getting the body dimensions down to what they needed to be. A small base die made a world of difference. Additionally, knocking the shoulder back more (.007 ish) to match the factory FGMM dimensions helped. I don't plan on getting more than a few reloads out of this stuff. (2) FGMM Primers is the secret to making this load work in my gun. WLR's had vertical stringing, still a MOA load but not like this.

It was touched on in this thread but I think there is real gains to be had by segregating FGMM brass by weight. The 100 round bag of once fired I used to load this up varied by as much 8 grains. I ended up with around 85 of them that fell between 176-178.5.

 

[ArmyJerry]

This is a great thread

 

[maximvickers]

Dan gave me this load information back in May when myself and two friends attended his long range shooting class. In our discussion I said I could not load anything that shot as well as the FGMM ammo in my 308. So I took his info home with me. Loaded up ammo using prepped FGMM brass, GM210M primers, 42.8 grains of IMR 4064. This picture shows my best 5 shot group at 100 yards.

 

[mveto]

Tagging this for later, need to find some 4064 and give this a go. Great read.

 

[sib1948]

I've found IMR 4064 42.8 gr is the best load for SMK 168 & 175 gr bullets. Berger 185 gr VLDs require 43.9 gr IMR 4064 for best performance!

 

[secondofangle]

I stumbled across this thread, and it reminded me of 1998 when I had my first M1A rifle and I was reloading for it and contrary to my previous reloading experiences, I COULD NOT beat the 168 grain FGMM load. In fact, my reloads were WORSE than the FGMM ammo, to my chagrin. So I resorted to doing just what Dan did, and 16 years ago I tore apart a FGMM cartridge and identified IMR 4064 as the powder with about 41.5 grains IIRC in those days, and BINGO. 1/2 MOA reloads just like the factory loads. Talk about reverse engineering.

I was a big federal brass guy from the early 1990s forward, then when I started reloading magnum cartridges in 2004 after a several year hiatus in reloading, somebody on the ar15.com forums told me to stay away from federal brass, it's too hard and doesn't work well with repeated firings. After that I went to Win and Nosler brass and have never looked back.

 

[M40_A1]

...told me to stay away from federal brass, it's too hard and doesn't work well with repeated firings.

Actually, the common understanding is that it's too soft, and the primer pockets open up after a few firings, even with "moderate" loads. Unfortunately, Lapua seems to have become this way lately as well.

 

[DMcyclocross]

Tag for reference.

 

[Aimsmall55]

This is a great thread. Many thanks to Dan for getting it rolling.
I was shooting with Sean Little a few months ago ( Sean owns Vapor Trail Tactical.. A training course. He is a well known Former Marine Scout Sniper and helped test and design the newest addition of the M118LR military sniper ammo, and he told me that in his basic conclusion during all the test was that 42.0 IMR 4064 with a 175 shot the "most consistently accurate and repeatable of all loads tried". He also said it didn't matter what brass you used... Lapua, Lake City, Federal ect... 42.0 was it. They were shooting the M24 and M40. That being said I took him up on the idea to try 42.0 with a 178 amax out of a .308 Custom with a Stiller Tac 30 action , a 28" HV Bartlein 1:11.25 and boy oh boy. Guy knows his stuff.



FYI. , the dot is 3/4" sticky I bought at Walgreens.



I loaded up 60 rounds but just haven't had time to shoot at distance. However , the SD and ES were really low with an average MV of over 2700 fps.

 

[Aimsmall55]

Anyone try this load with the 178 amax, shoot any good any adjustments needed?

Read below

 

[corn_dork]

Well I haven't taken the time to really read through what everyone on here has said, but I wanted to share what I've experimented with. I did see the spec sheet posted on the first page for the load and figured I'd try it to the letter and shoot it next to Federal 175gr SMK load. And I mean to the letter, Federal GMM cases (FL sized and trimmed to 2.005"), 41.74gr IMR-4064 (weighed on a Gem Pro 250), Federal GMM large rifle primers, Sierra 175gr SMK, COL 2.82"...here's what I got. Also my rifle has a 22" barrel in case you're all wondering.

<a href="https://www.flickr.com/photos/126861136@N03/15488698582" title="IMG_2165 by Ned Champness, on Flickr"><img src="https://farm4.staticflickr.com/3937/15488698582_62645e9245_z.jpg" width="480" height="640" alt="IMG_2165"></a>

And here's Federal GMM 175gr SMK factory ammo...

<a href="https://www.flickr.com/photos/126861136@N03/15465939496" title="IMG_2166 by Ned Champness, on Flickr"><img src="https://farm3.staticflickr.com/2948/15465939496_38883857f5_z.jpg" width="480" height="640" alt="IMG_2166"></a>

Damn near same point of impact and within almost 20fps of each other.

 

[Aimsmall55]

Well I haven't taken the time to really read through what everyone on here has said, but I wanted to share what I've experimented with. I did see the spec sheet posted on the first page for the load and figured I'd try it to the letter and shoot it next to Federal 175gr SMK load. And I mean to the letter, Federal GMM cases (FL sized and trimmed to 2.005"), 41.74gr IMR-4064 (weighed on a Gem Pro 250), Federal GMM large rifle primers, Sierra 175gr SMK, COL 2.82"...here's what I got. Also my rifle has a 22" barrel in case you're all wondering.

<a href="https://www.flickr.com/photos/126861136@N03/15488698582" title="IMG_2165 by Ned Champness, on Flickr"><img src="https://farm4.staticflickr.com/3937/15488698582_62645e9245_z.jpg" width="480" height="640" alt="IMG_2165"></a>

And here's Federal GMM 175gr SMK factory ammo...

<a href="https://www.flickr.com/photos/126861136@N03/15465939496" title="IMG_2166 by Ned Champness, on Flickr"><img src="https://farm3.staticflickr.com/2948/15465939496_38883857f5_z.jpg" width="480" height="640" alt="IMG_2166"></a>

Damn near same point of impact and within almost 20fps of each other.

That's crazy!! Id say your SLEUTHING THE HELL OUT OF IT. Great info!!

 

[M40_A1]

Well I haven't taken the time to really read through what everyone on here has said, but I wanted to share what I've experimented with. I did see the spec sheet posted on the first page for the load and figured I'd try it to the letter and shoot it next to Federal 175gr SMK load. And I mean to the letter, Federal GMM cases (FL sized and trimmed to 2.005"), 41.74gr IMR-4064 (weighed on a Gem Pro 250), Federal GMM large rifle primers, Sierra 175gr SMK, COL 2.82"...here's what I got. Also my rifle has a 22" barrel in case you're all wondering.

For reference, was the range 100 meters as the targets say? And what size are the squares? Thanks.

 

[918v]

What's nice about that load is it delivers .5 MOA accuracy and single digit SD.

 

[SDLocal76]

Tag

 

[sig2009]

Does anyone have any measurements on the 175gn GMM base to shoulder?

 

[Downtown]

This may help, but this thread is four years old and the original posters may be long gone.

 

[sig2009]

Thanks. Just what I was looking for. Yes. I found the thread yesterday.

 

[Downtown]

Pleased to be of assistance.

 

[sig2009]

Thanks again

 

[Shootingblanks]

Awesome thread.

 

[riverside jeep]

great info, thanks guys!

 

[edd1e22]

Has anyone sleuthed the FGMM 185gr juggernaut load? If so, would love to get the data as I just got some projectiles I'd like to load up to match.

 

[Billiam1211]

My 308 shoots 175gr FGGM into 1-inch groups consistently at 200 yards. I've tried IMR 4064, RL-15, Varget, and H4895 and a few other powders and a whole ton of bullets. If there's anything I've learned, it's that shooting a ladder test and running with the best shooting group is still the most efficient way to go.

If I didn't live in a crap state, I'd run 175gr FGMM and be done with it. It's actually easier for me to order powder and bullets and reload since I can't have ammo delivered to my house :|