AR10 using 178gr Horniday ELD-M Bullets Powder Suggestions

[KittieKatt]

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]

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

 

[RegionRat]

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]

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]

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]

.. 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]

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