AR10 using 178gr Horniday ELD-M Bullets Powder Suggestions

KittieKatt · Dec 24, 2024

I have a 20" rile gas system ballistic advantage 1:10 twist barrel on an AR10.. I looked for some bullets and found the 178gr ELD-M bullets with a great BC and a decent price..

We tried Varget as the first powder and I am questioning if the gun just does not like it. We tried 41.7gr, 41.9gr, 42gr, 42.1gr, 42.2gr, and 42.3gr.. our best standard deviations were at 41.9gr followed by 42.1gr.. but we could not get a group better than about 2-3 inches at 100 yards.

The husband had this same issue with his AR15 a few years back and swapped powders and it took it from 2-3 inch groups to sub moa.. I am wondering if this is a similar case.. I am thinking it may be..

What are some loads people are getting sub moa groups with for an AR10? powder, grains, OAL?

Cascade Hemi · Dec 24, 2024

There is no guaranty any known load will be sub MOA in your rifle. Alternate powders to try are 4064, RE15, 8208, etc.

RegionRat · Dec 24, 2024

We will assume this is 308 WIN based on it being an AR10 sized rig and the bullet weight.

It is probably the bullet and not the powder, but that is just a guess based on lots of years of experience with SR and AR10s.
We can only guess from the keyboards. I have not used the Ballistic Advantage barrels so I don't know what reamer they run.

H4895
IMR4895
IMR4064
N140
N150
RE-15
W748
H335
etc.

Varget is in the right neighborhood for an AR gas system in 308, so the rig should have shown you much better performance. But don't give up yet.

I'll show you a list straight from Hodgdon that is good for the 308 gas system.

Depending on the chamber, you may want to try a less aggressive tangent ogive like an SMK and see if there isn't a drastic improvement right at magazine length.

It may be possible to get a box of FGMM ammo to make the trial less painful. You would get a preview without too much effort or needing to sit on components you abandon. Just my opinion, but a 308 AR that doesn't run FGMM under 1.5 MOA is not a good sign.

For background, has this rig ever shot tight with any other recipe?

The Varget you started with in this thread is one of the most popular ones for your rig, and known to be above average due it the properties. Service Rifle loads are usually lower pressure than bolt gun loads because they also need to be kind to the gas system and Varget does pretty good in those respects too.
I'll paste in some of the Hodgdon web site data for a 175 grain load and you will see the list of other powders for the Service Rifle as well as the bolt guns.

You can see that the Varget should have shown you something in the neighborhood of 42 to 43. I would tell you to try H4895, but you cannot find that these days and I honestly don't think the odds are it will solve your issues based on what we know now.

If the rig has ever shot any other bullet well, I would never tell you not to try those 178 ELDM but you may want to mimic the bullet style that already worked, that is if there is one?
Merry Christmas and Happy New Year!

KittieKatt · Dec 24, 2024

RegionRat said:
We will assume this is 308 WIN based on it being an AR10 sized rig and the bullet weight.

It is probably the bullet and not the powder, but that is just a guess based on lots of years of experience with SR and AR10s.
We can only guess from the keyboards. I have not used the Ballistic Advantage barrels so I don't know what reamer they run.

H4895
IMR4895
IMR4064
N140
N150
RE-15
W748
H335
etc.

Varget is in the right neighborhood for an AR gas system in 308, so the rig should have shown you much better performance. But don't give up yet.

I'll show you a list straight from Hodgdon that is good for the 308 gas system.

Depending on the chamber, you may want to try a less aggressive tangent ogive like an SMK and see if there isn't a drastic improvement right at magazine length.

It may be possible to get a box of FGMM ammo to make the trial less painful. You would get a preview without too much effort or needing to sit on components you abandon. Just my opinion, but a 308 AR that doesn't run FGMM under 1.5 MOA is not a good sign.

For background, has this rig ever shot tight with any other recipe?

The Varget you started with in this thread is one of the most popular ones for your rig, and known to be above average due it the properties. Service Rifle loads are usually lower pressure than bolt gun loads because they also need to be kind to the gas system and Varget does pretty good in those respects too.
I'll paste in some of the Hodgdon web site data for a 175 grain load and you will see the list of other powders for the Service Rifle as well as the bolt guns.

View attachment 8576585

You can see that the Varget should have shown you something in the neighborhood of 42 to 43. I would tell you to try H4895, but you cannot find that these days and I honestly don't think the odds are it will solve your issues based on what we know now.

If the rig has ever shot any other bullet well, I would never tell you not to try those 178 ELDM but you may want to mimic the bullet style that already worked, that is if there is one?
Merry Christmas and Happy New Year!

I guess I missed a bit in my post trying to give all info.. yes it is 308.. This is a brand new build and thus far we have only shot that bullet out of it.. I had started with it because of the BC and wanting to try long range with it.. If you have another suggestion on bullets I am all ears.. We did try factory load for Horniday ELD-M 178gr rounds.. the results were not good.. you mention a FGMM factory loaded bullet. what is that one?

KittieKatt · Dec 24, 2024

Cascade Hemi said:
There is no guaranty any known load will be sub MOA in your rifle. Alternate powders to try are 4064, RE15, 8208, etc.

I am well aware of this.. but I also know that with this being a brand new rifle build that getting input from others on things that have worked in a similar build gives me a narrower starting point than just everything but what I have tried thus far..

RegionRat · Dec 24, 2024

KittieKatt said:
.. you mention a FGMM factory loaded bullet. what is that one?

One of the first things to try and take advantage of, is history.
https://snipercentral.com/history-m118-ammunition/
When you think about the M14 in 308WIN and all the GOV research behind that evolution, it should be viewed as an advantage since their budgets are huge compared to an individual's.

Try to stick with the 175 Sierra Match King version rather than the 168 SMK. The 175 SMK will handle flying through sonic transition much better than the 168 SMK, so if you ever to make it out past the 600 yard line, the 175 SMK will be in your favor.

Cascade Hemi · Dec 24, 2024

KittieKatt said:
I am well aware of this.. but I also know that with this being a brand new rifle build that getting input from others on things that have worked in a similar build gives me a narrower starting point than just everything but what I have tried thus far..

You didn't list your brass. A 10 or 15 shot pressure ladder is your friend. 178ELDM isn't very common so getting known data may be a challenge. 168SMK and 175SMK are more friendly to that platform and have tons of load data. There is also a 308 service rifle load data thread.

308 Winchester AR Only

post your 308 AR loads here

www.snipershide.com

KittieKatt · Sunday at 7:19 AM

Cascade Hemi said:
You didn't list your brass. A 10 or 15 shot pressure ladder is your friend. 178ELDM isn't very common so getting known data may be a challenge. 168SMK and 175SMK are more friendly to that platform and have tons of load data. There is also a 308 service rifle load data thread.

308 Winchester AR Only

post your 308 AR loads here

www.snipershide.com

We are using Lapua brass first use. We did try the 168gr ELD-M with Varget (43.2, 43.4, 43.6) this weekend.. accuracy was still not as good as I wanted.. but it did seem better than before. I need to still put the speeds and such into my spreadsheet to see SD and all that jazz.. it seemed like 43.4 was the best.. I had 4 rounds (two of them keyholed) within 1/2" ish.. 2 more almost keyholed just about 1/4" away..

wvfarrier · Sunday at 8:13 AM

N-550 has been working well for me.

Doom · Sunday at 12:06 PM

Let's get this up front a little late in the process. The 308 chamber is not likely to be friendly to any ELD-M bullet, especially when limited to magazine length. It can happen but that bullet is a secant ogive bullet and the chambering is designed around a tangent ogive bullet. That is why the 168 and 175 SMK bullets are the standard in the 308 in terms of accuracy.

You didn't mention the SD but that is mostly about case preparation. With Varget or IMR 4064 you should be about 43 gn +/- and about 2550 fps with a 168 gr bullet and 42 gn with a 175 gn bullet at 2500 fps. As for other powders the standard has been IMR 4064 and H4895 for years. In newer powders AR-Comp or similar has been used in the FGMM series. This is not a long range cartridge. It is realistically a 800 yd cartridge in a 24" bolt action rifle. In a 20" barrel it is more of a 600 yd rifle.

The 308 is probably has the most information of any cartridge in history. It's simple to load for but you have to have realistic exceptions. In an AR platform get real sub MOA consistently is very good. Getting less that .75 MOA is excellent. Pushing for higher velocities is like to not improve accuracy.

The advice from @RegionRat is spot on.

secondofangle2 · Sunday at 12:47 PM

I agree with trying FGMM 168 or 175. I could never beat that with reloads in my gassers.

Since you can’t find RL15 ANYWHERE, I’d get some IMR 4064. And use Sierra SMK not ELD-M

sinister · Sunday at 2:50 PM

Self-loading rifles seldom feed and shoot VLD and ELD bullets well -- they tend to be longer than magazine length for best contact seated to the leades or with minimal free-bore jump. Highpower shooters will single-load them through the ejection port door for medium-range (600 yards) and long range (800, 900, and 1,000-yard) matches in the Service Rifle category.

A magazine-length Sierra 168 will usually go around 850 yards before showing trans-sonic transition issues. A Sierra 175 needs 2550 fps muzzle velocity to stay stable and accurate to 1,000 yards.

Original poster's rifle photo shows it on a bipod. Take that off and build your most solid, consistent firing position off sandbags (fore-and-aft).

redbullitt · Monday at 2:15 AM

I agree with the above comments suggesting a bullet more like the 168 or 175 smk. I bet that ogive shape will be much friendlier to a magazine length restricted rifle. Depending on what you need the rifle to do, that bullet may be just fine.

I've had very good luck with 42.5 +/- grains of varget and a 175 smk in several ar10s. I only spent a little time with the eldms there... OK results, but didn't want to waste them when my bolt gun loves em and the ar10 does great with 175s.

For giggles, you could try a quick workup of single feed 178eldm not seated to mag length, but close to the lands. Likely not worth it other than curiosity... and primer cost now has really curbed my curiosity lol.

Totally agree with above posts to try some 168 or 175 fgmm to get a baseline.

I see mention of keyholes? Nothing you're shooting should be even close to keyholing. If you can rule out weird holes from target backer etc, then I'd be looking there for issues to explore. 168g supersonic keyholes should not be happening here.

Maybe we should be looking at the barrel a bit, the gas port, muzzle device, crown etc to figure out the keyholes.

Some photos of bore and crown could be helpful!

tekmann2377 · Monday at 4:53 PM

A few things, use a good rest IE sandbags instead of a bipod, try good quality factory ammo (FGMM), and give some other bullet weights a try (155-168 gr). You are much more likely to get tangent ogive bullets like the 175 SMK to shoot more easily.

It may also be possible that your BA barrel does not shoot that well either. If you try the above and are unable to develop a consistent load of adequate accuracy the barrel may just suck and the best solution is replacing it with something better shooting, instead of wasting $$$ of components.

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AR10 using 178gr Horniday ELD-M Bullets Powder Suggestions

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