How can I get my 308 reloads to be as good as out of the box168gr Fed GMM

[hank jacobs]

How can I get my 308 reloads to be as good as out of the box168gr Fed GMM which shoots sub .5 moa out of Rem 700 SPS Tactical

Hi everyone, I am a newbie here and hope to get to get some advice.
I started reloading 4 months ago and am still not able (after 400 rounds) to match Fed GMM.

To cut the story short I am currently trying to reduce the variables and decided to pull the bullets from the FED gold medal match 168 gr factory loads to reseat them into the original brass leaving primer, powder charge, seating depth, unchanged.

I used the following procedure:
A) Unload fed 168 GMM using Unload Hammer
B) Necksize unloaded brass either using a
Lee collet die
and more recently I have also be trying an
RCBS neck sizer with expander ball
C) Refill with Orig. Powder and Re-seat the bullets to original depth using lee seater (nothing special)
D) Measured bullet runoff to make sure it on par or better than what it was.

I have been very carful at this and repeated this now several time. However back at the range I can only get 0.8-1MOA with these which means something is already off either with the seating step or with the neck tension..? or with something else? Before unloading (to reduce the variables) I was reloading adding many more steps. Results were 0.7-1 MOA as well but I had no clue where the problem could be. Now the error needs to be in steps A-D above. But where?

What should I do…?

In a few weeks I should be getting a few more dies to try. Specifically a 1. Forster Ultra Micrometer Seater Die and a 2. Redding Competition Bushing Neck Sizer Die together with a 336 Diameter Titanium Nitride Bushing to see if this helps.

Anyway I am getting frustrated that I cannot get close to what the factory ammo delivers. And that I have to keep buying stuff without getting anywhere near the factory loads..

Can someone shine some light into what is going on?

[jwrowland77]

....

[overthere]

If I am reading it you are essentially taking the GMM cartridges apart and then reassemble using the same powder and bullet (after neck sizing) is that correct?

How do the bullets look after you pull them with the inertia hammer? I have had cases where the tips of the bullets get a bit banged up when I use an inertia hammer, even if I have padding at the bottom of the bullet catch.

To eliminate that as a variable you could try seating new Sierra MK 168s instead of the pulled ones.

[hank jacobs]

bullets look ok. and I do have some sierra MK 168 as well so I will try them next time..

Yes original power

[kilimanjaro]

Try the new bullets as mentioned, that might work.

Are you weighing the powder charge, checking that?

Part of me is saying, "Perfect is the enemy of good".

How are your loads doing with new brass, new powder, new bullets?

Take your mike and see what a fired reloaded round measures out before resizing, and compare it to the fired factory round before resizing, and then compare to a factory round. Shoulder, angle, neck length, etc.

[Jimro]

Ok, if you want to duplicate Fed GMM...

Buy Sierra 168gr SMK bullets.
Buy virgin Federal Premium brass.
Buy Federal GMM large rifle primers.
Buy a jug of IMR4064.

Assemble the rounds, do a ladder charge, five rounds each with the following charges.

41.5
42.0
42.5
43.0
43.5

Five rounds each.

Find the two groups that impact closest to your FedGMM lot.

Then fine tune the powder charge until the POI is the same between your handloads and the commercial lot.

Don't expect the same performance after the brass has been shot once.

Jimro

[1stmar]

So out of the box they shoot .5 moa and your reloads are .8 moa? How many shots in a group? How many groups n the avg? What distance? Did you compare on the same day?

Bottom line do you have enough statistical data and a solid base as well as the same conditions to say there is a difference ?

[hank jacobs]

1stmar, I think I do have enough statistical data. Total 40 rounds of delaborated have been shoot and over the last year 500 factory loads of FED GMM. On the days of the comparisons I did shoot 10 rounds factory and 10 rounds reassembled, gain 4 different days

Here the data on the FED GMM that I acquired from 15 rounds

Out of the box Concentricity Most about 0.0025’ a few better a few worth .. 0.003’
Brass 183gr std 1gr Maximal 2gr range
Powder 42.74 gr std 0.23gr Maximal 0.62 gr range
Projectile 168.3gr std 0.06gr small*. Maximal 0.12gr range
Length 71.05 mm STD 0.0021
Case Length 50.93mm STD 0.0012
Bullet Length 30.48 mm STD 0.0023

* need to repeat this one to confirm this unbelievable number, out of the box Sierras MK 168 gr have a larger spread..

I wanted to establish these numbers to know what is needed to get 0.5 MOA in factory loads..

I kept within this range when I reassembled… Powder loads were adjusted to be within 0.03 gr .. again using the powder that is inside the factory FED GMM ammo. Anyway, I still believe that something is going wrong in the reseating or neck sizing..

What could this be..?

[F. Guffey]

I exercise the leaver policy, I do not purchase new ammo but, if I did I would leaver like I founder.

In a few weeks I should be getting a few more dies to try. Specifically a 1. Forster Ultra Micrometer Seater Die and a 2. Redding Competition Bushing Neck Sizer Die together with a 336 Diameter Titanium Nitride Bushing to see if this helps.

Anyway I am getting frustrated that I cannot get close to what the factory ammo delivers. And that I have to keep buying stuff without getting anywhere near the factory loads..

I would suggest you find someone that gets results with fewer tools that are not expensive. Then I have to ask: Is this a plug for Federal GMM ammo?

F. Guffey

[1stmar]

Hank how many shots in a group did you shoot? I believe the metrics you are looking at ( bullet weight, run out. powder charge variation...) are all within the acceptable range and well within the variability you would get from fed gmm. If you are simply using neck sizing dies, how many times has the brass been reloaded? Lee collet die should perform well for you, the neck tension should be sufficient for what you are doing if you follow the adjustment steps. Do you size rotate case and resize again?

[Rimfire5]

I'm not sure whether you are trying to just duplicate Federal match ammo or trying to get the best accuracy out of your rifle.

You've picked the 'gold standard' of .308 ammo to try to duplicate.
You may not know that there are actually 2 different Federal Premium Gold Match factory ammos that use 168 SMK bullets. The older, now discontinued, Blue and Buff colored box was loaded at 2600 fps muzzle velocity and the newer Maroon and Gold box is loaded at 2650 fps.

I have used both versions and found my rifles seemed to shoot the older 2600 fps ammo slightly better. That led me to testing velocity variations to see what the rifle liked best. I still have a few boxes of the old Blue and Buff around to test new rifles.

First, have you determined whether the Federal Premium Gold Match SMK factory ammo uses Federal 210M or 210 Large rifle primers. For me the 210M match primers gets slightly better results.

I have 3 Savage bolt action .308s that I load for and have loaded just under 9,000 .308 rounds over the last 3.6 years. I have used Federal, Remington, Winchester, Nosler and Lapua brass with 210 and 210M primers and have gotten good results with all of them so the brass wasn't the differentiator. I have settled on Lapua brass with Federal 210M match primers based upon results and because Lapua brass seems to keep consistent neck tension over more reloads per case. In fact, my Lapua brass cases get retired when the primer pockets get loose after about 16 reloads not when the necks split or neck tension begins to vary as is the case with the other brands of cases.

Two of the Savages have more 175 grain bullets in (9) their top 25 loads than the 168 grain bullets (8) and the other has more 168 grain bullets (23) in its top 25 loads. The other bullets are all 150/155 grain bullets.

Almost all of my best 168 gr loads (all better group averages at 100 yards than factory Federal Gold Match 168 gr SMKs) with the .308s with 5 different powders. The 8 top 25 loads with two of the rifle are 168 gr loads and are generally loaded slower than factory speeds. The slowest load in the most accurate 168 grain loads was 2525 fps and the fastest load of the top 168 loads with each bolt action rifle is 2625 fps. The other rifle has 23 of 25 of its top load using 168 grain bullets and the fastest 5 are 2675 fps. It is what the rifles perform best with using the powders that I have tested. Only one of the rifles has some of its 168 grain loads faster than 2650 fps muzzle velocity. That rifle also happens to have a very deep chamber compared to the two other newer Savage rifles.

I have had the best results with N140 and H4895 powders with all three rifles. 80% of the top 25 loads with each rifle used N140 powder.
Reloader 15 and Varget have had better than factory results with some loads but not good enough compared to N140 and H4895 to make the top 25 loads in each of my .308 rifles. The preponderance of N140 in the top 25 loads may be due to its superior metering versus the larger grain powders.

If you want to get the best accuracy from your rifles, you probably need to experiment with different powders rather than just pulling factory ammo apart. Factory ammo tends to favor velocity over accuracy because velocity sells. My rifles seem to shoot best a speeds slower than factory speeds. Most shoot best when the seating depth is matched to the individual rifle's chamber depth. My rifles generally like to have bullets seated 20 thousandths shorter than the measured chamber depth.

I think your approach to duplicating the Federal Gold Match SMK ammo to achieve the best accuracy is not practical because:
1) you probably can't duplicate the neck tension of the factory after pulling the bullets and resizing.
2) it is too expensive to waste the good factory ammo that sells for up to $36 a box. I'm loading my most accurate loads for $ 9.40 a box.
3) there are probably better powders you could find that your rifle prefers if you did some experimentation.
4) you can't buy the exact powder over the counter that Federal uses even presuming that they consistently use the same powder mix over a long period of time. (I have also been told by three different people that claim to know that Federal uses "xxx" powder in their Gold Match .308 ammo - all claimed a different powder. So much for people in the know.) Good luck finding out what Federal actually buys each time they buy their huge lots of powder.

Admittedly, I have experimented with powders, velocity, and seating depth to get the best accuracy. I have never tried to use "factory powder", mainly because I could never afford to buy that much factory ammo to pull apart and, secondly, I never believed that the factory ammo necessarily used the best available powder.

[jwrowland77]

I agree with all the above except #4. The powder they use in their gold match is IMR 4064, which you can buy. It says right on their msds sheet IMR 4064. I have 15lbs of it sitting in my house.

[hank jacobs]

Hank how many shots in a group did you shoot?
5 shots

I believe the metrics you are looking at ( bullet weight, run out. powder charge variation...) are all within the acceptable range and well within the variability you would get from fed gmm. If you are simply using neck sizing dies, how many times has the brass been reloaded?

this was the brass and powder and original bullet pulled apart and put together again to test if the neck sizing and setting is reducing the accuracy in my setup.


Lee collet die should perform well for you, the neck tension should be sufficient for what you are doing if you follow the adjustment steps. Do you size rotate case and resize again?

[COLOR="rgb(160, 82, 45)"]No[/COLOR]

[hank jacobs]

I am not sure if I was sufficiently clear. But I think something is wrong with neck tension or seating.. The goal of this exercise to take apart the factory ammo that perform well is only to test if it still performs well if I put it back together. If not something is not right in the way I do things..
Again I know that my error needs to be there.
Unless the assumption is wrong that you cannot take apart a Factory loaded ammo and put it back together and assume that it will shoot the same even so the case, load, bullet, and seating depth is the same?

[jwrowland77]

I've taken apart factory ammo that was given to me to make it more consistent powder wise, but it shot better after I out stuff back together.

Are you resizing the neck after taking apart to get proper bullet hold? Or are you just seating the bullet and relying on the bullet hold that's still there after taking bullet out?

[hank jacobs]

i am neck sizing using lee collet die.. and perhaps this is where the problem is..

[Unclenick]

There was a claim from a board member that at one time the powder in the GMM was switched to Reloader 15, but I know the Mk 316 M. 0 sniper ammo Federal put together to improve the high temperature performance of M118LR dropped the RL15 and went back to IMR4064. I expect the GMM followed suit.

Note that the process for IMR4064 has changed. The old process was dropped by Valleyfield plant in Canada that makes it as too expensive and inefficient,. A report by a board member at The Shooter's Forum was the new version has a shorter, fatter looking grain. I've not seen any myself, and am anxious that a different grain configuration may not provide the same equivalent immunity to exact charge weight that the old version seemed to provide.


Hank,

Several possibilities occur to me. One is that the inertial bullet pulling is lengthening the case slightly and changing the shoulder angle slightly near the neck. Federal cases are notoriously soft to begin with, and are even softer in the annealed area at the neck and shoulder/ The ability of the cases to self-center as the firing pin drives the shoulder of the case forward against the chamber shoulder is important to accuracy. If it extends even slightly near the neck and shoulder junction, that can jam the throat before centering the rest of the case and may even tip the bullet slightly.

A second thought is that you are changing the bullet pull unfavorably or making it less consistent. For one thing, after the bullets are seated in the brass for awhile, they bond to it slightly, increasing bullet pull. This is why SAAMI pressure standards include a value called the Maximum Probably Lot Mean (MPLM), which is a higher pressure than the Maximum Average Pressure (MAP) that the ammunition is loaded to. It is to allow that pressure can increase over the life of the lot, and allows future random samples may average higher than the MAP. If you are introducing variability in the bullet pull, you will likely also have increased MV SD over your chronograph. That and average velocity difference are the first two comparisons I would have made after finding the precision difference in the two loads.

Also, when you use the inertial puller, you are probably spreading some graphite powder from the powder grains up against the neck. That will tend to reduce bullet pull and lower mean velocity if it is happening. Again, a chronograph would tell you.

The Lee Collet Die is a great tool, but it has a learning curve. It is easy to size inconsistently with it if you use a fixed stop, as the brass doesn't always have exact same thickness all around from one case to the next. Also, many folks end up using a drill and 600 grit wet/dry sandpaper to adjust the mandrel diameter of these dies down a half thousandth or so for slightly more bullet pull if they are having consistency problems.

Try standing on a scale and seeing that your pressure on the handle is the same from one case to the next. You can also stand on the scale during seating to see if the seating pressure is consistent. If not, you've introduced a variable. Buying new Federal brass to load as-is would let you get a comparison., but, again, you should also see an increase in MV SD with your chronograph if you are not being consistent with seating and bullet pull force.

One test for the above issues, collectively, would be to partially pull and then reseat some GMM rounds and see if they still producing the same velocity and are still grouping as well as before. If loosening the neck grip drops velocity and precision, the neck bond may be an issue as may the graphite.

Did you decap and re-prime when you used the Collet die? If so, primer seating variation can cause serious accuracy issues. It's because an inadequately seated primer can suffer short ignition delays. These are on the order of milliseconds, so the shooter can't tell they've happened by sound or feel, but it has the same effect as having your gun's lock time varying. The exact position of the muzzle is affected by firing mechanism vibration and shooter muscle variability, so, if the lock and bullet barrel times aren't consistent, it winds up slightly off position at bullet exit. Mostly, not seating primers hard enough is the issue.

Finally, it has been observed before that cartridges that have been transported can shoot at lower pressures than those loaded at the shooting bench. This is because vibration packs the powder some. It happens in the measure and again in the shipping and other transportation. One technique that can help mimic this is to charge the case, then hold it against the lid of an operating vibratory tumbler to settle the powder before seating. A drop tube can help, too. You could try doing the vibration afterward as well, but it may take longer as the pre-seat settling is less likely to be jammed by compression. The old GMM I have was all slightly compressed.

[hank jacobs]

rimfire thanks for the response.. again I was doing this to reduce the variables since I have not seen any sub moa using my reloads.. So something is wrong..

In the reloading experiments prior to what is described above I used the n140 and n150
I did start out with the n140 41gr, 41.5gr, 42gr, 42.5gr, 43gr but everything was around 1 MOA, bullet 168 sierra match kings. Not done much with the n150, only produced hunting rounds with 44gr also about 1MOA. It provides a better case filling.

Where is the sweet spot in your rifles using the n140.. ?

I might give this a second try...

[Brian Pfleuger]

I wonder:

Measure concentricity as purchased. Measure concentricity after pulling and before sizing. Measure after sizing and before seating. Measure after seating.

(Oh, and listen to UncleNick. He's the samurai guru ninja master jedi of this stuff.)

[lll Otto lll]

i am neck sizing using lee collet die.. and perhaps this is where the problem is..

Duplicating Federals neck tension would be better accomplished using a Redding Type S neck sizer.
The Lee collet die can be made to work but you'll need to experiment with different sized mandrels.
What ever you do, don't run an expander ball through the neck.

[Jimro]

Try 42.3 gr of N140, or 42.5gr of N150. According to Sierra that should be about 2600 fps under a 168SMK.

Also try some different primers, Wolf Large Rifle is a good place to start, as are CCI BR-2s.

Jimro

[cw308]

Hank, Did you measure case length of the Federal round before removing the bullet. Than neck size to the same case lenght & OAL to the ojive. I can understand what your doing and why it wouldn't? I reload with Federal FC 308 cases, fed. 210M primers, IMR 4064 40.5 grains & neck size with RCBS standard neck die. Works very good for me 3/4" and better at 200 yds. I shoot 20 timed rounds per range trip and yes I clean after every shoot. I camover slightly when neck sizing with almost 0 headspace .010 jump.You checked the runout, I would agree it's somewhere in the case neck.

[Bart B.]

One difference between ammo is the new cases are full length sized to minimum specs and the resized fired ones are neck only sized. I've never got best accuracy with neck only sized cases. New ones always shot bullets best. Full length sized .308 cases have produced best accuracy for decades. Dies without expander balls with neck diameter a couple thousandths less than a loaded round makes the straightest case necks on cases and lets bullets have the least runout.

Another difference may be case heads. New cases have case heads quite square with the case axis. If the rifle's bolt face is out of square with the chamber axis, firing a new round will flatten its head against that bolt face. Sizing it won't make its head squared up again. When that round is fired, it will impact the bolt face different ways each time. That causes the barreled action to whip more in one direction and the bullet will leave in a different direction than if everything was squared up.

If the resized case mouths have a sharp edge from trimming and debuting, it often scrapes off bullet jacket particles unbalancing the bullet. Pull some seated bullets from reloaded ammo and see if that's happening.

The primers used in reloads have a different lot number. The difference between Federal primer lots was why I quit using them. Tulammo primers may be the most consistant from lot to lot and they're a favorite with competitors. But differences usually don't show up at ranges 300 yards and shorter.

There's a 1 to 2 grain spread in powder charge weight where accuracy with 168's from .308 cases stays excellent. It's about impossible to tell what charge weight is best. A 3/10ths grain spread in charge weight will easily produce 1/4th inch accuracy at 100 yards. You don't need to weigh charges for use at ranges up to 400 yards.

Sierra 168's have good tolerance for how far back from the rifling they can be seated to. Hundreds of top ranked competitors seat them to a 2.800" cartridge length to fit box magazines. They'll shoot the same load over the 3000 round life of the barrel as the rifling erodes away increasing bullet jump to it by almost 1/10th inch. No significant loss of accuracy.

[hank jacobs]

lots of good suggestions..

Unclenick.. Well your writeup is very interesting and detailed thank you a lot. It gives me a lot to think about and try. I have prepared another 10 rounds that I will try tomorrow at the range.. if i get to it.. Again reassembled… don’t expect any surprise.. I will see if I can implement some of your suggestions next time I reload.. I will have to get a balance from the neighbor.. and yes bullet pull could be the cause.. Others are also suggesting that it could be in the neck…
So should I expect better consistency using a Redding Competition Bushing Neck Sizer Die? I ordered one.. and hope that this will be a fix.. Well only got one 336 diameter bushing which means not much to adjust in terms of tension. I do not have a chrono yet...

Your suggestion: "One test for the above issues, collectively, would be to partially pull and then reseat some GMM rounds and see if they still producing the same velocity and are still grouping as well as before. If loosening the neck grip drops velocity and precision, the neck bond may be an issue as may the graphite."… Will try this.. going down to the basement to prepare 4 …. done … will take them to the range.. and report back..

Your suggestion: "Did you decap and re-prime when you used the Collet die? If so, primer seating variation can cause serious accuracy issues.” yes you are right I did using the Lee die.. .. and honestly did not think about this…. what should I look for? checked the rounds for tomorrow..and they seem to be in all the way…

Again many thanks to the suggestions..



Cw308. Thanks for your response and questions as well: Back to your Questions "Hank, Did you measure case length of the Federal round before removing the bullet." No. I only measured the case length after pulling the bullets and it was 50.93 mm = 2.00512´ after unloading with unloading hammer..
Do you see an issue here?

your comment " Than neck size to the same case lenght & OAL to the olive." Yes, did neck size using lee collet die that graps the entire neck if this is what you mean… and NO did not measure OAL to the ogive.. only OAL to the tip. OAL to the tip was measure before (original) and in the reassembled rounds. They were pretty close. Do you see an issue here?


"I can understand what your doing and why it wouldn't? I reload with Federal FC 308 cases, fed. 210M primers, IMR 4064 40.5 grains & neck size with RCBS standard neck die. Works very good for me 3/4" and better at 200 yds. I shoot 20 timed rounds per range trip and yes I clean after every shoot. "


CW308 How do you clean? just curious… I was told not to clean … AND in terms of primers I got GM210M as well to play with once I got the neck tension bullet setting issue worked out.


"You checked the runout, I would agree it's somewhere in the case neck

This gives me some confidence that it might be in the case neck..

[cw308]

In measuring the case lenght,I was wondering if you were changing the shoulder of the case when you are resizing, If you measured OAL from head to tip, your measurements are close, but from the ojive is much more accurate. Preping my brass, I go alittle overboard, but I only shoot 20 rounds at a time. With 20 rounds I use the same cases each time,until any kind of problem, such as loose primer pockets or splits,than I dump all 20. I tumble the brass every time, clean the inside of the necks with a 30 cal bronze brush,clean the outside of the necks & base of the case with a few twists using 0000 steel wool. Neck size with a standard RCBS neck die,with a slight cam over, lightly lube inside & out of the necks than clean with alcohol,uniform the primer pockets, trim cases each time to 2.010 chamfer necks inside & out, and last I press the case mouth into the 0000 steel wool pad to smooth things up. Told you I go alittle overboard. My seater is the Redding comp. die. Hope I helped in some way. Chris