6 ARC powder consensus for heavies in AR

LEVERevolution (LVR) is probably the best optimized powder for the cartridge, giving the best balance of velocity/pressure. It’s dirty AF though, especially suppressed, but that’s a small price to pay for performance.

CFE223 is also in the same zone though not quite as popular.

I’ve tested a lot of different powders for 6ARC shooting 95s to 110s and LVR basically works best across the board. If you wanted to choose a powder that was also good for .308WIN, for example, Varget and TAC are decent options. I didn’t get great performance out of them, but not bad. N540 kind of surprised me how well it shoots, though velocities were about 100fps slower out of a 16.5” barrel.

The reason we all end up with so many powders is different barrels like different powders. You should probably get a load sorted and then when you know what shoots best buy more of that.

For Grendel based cartridges you can shoot anyone of:

TAC
8208
4895
Varget
CFE223
LeverRevolution
2520
StaBall

H4350 is tool slow, but you can use Varget with 6ARC. It’s just not a great powder for it, from what I’ve found.

+1 on LeveRevolution being the general favorite for 6ARC. It's a progressive burn-rate powder, so it maintains peak pressure for a longer time interval, hence where the velocity comes from. Downsides are it can be dirty, and some have found it to have a high ES.

As @Dogtown said, Vit N540 is another good choice, cleaner, but a bit less velocity. Also, it has a very hot flame temp due to the nitro glycerin (double-base), so barrel life can suffer. N140 is cooler (single base), but you'll sacrifice another ~50ft/sec.

A final one I hear mentioned often is AA2520. Less velocity again, but good ES/SD and clean. Just tends to be temp sensitive.

And when I say "N540 kind of surprised me", shooting ten round strings with a variety of powders loaded nowhere near max, N540 produced noticeably more consistent results (lowest SD/ES and tightest MR). Specifically I was using 26.5gr of N540 with 103 ELD-X and GM205MAR loaded to 2.245" COAL. But it's still kind of slow at 2350fps and might be worth playing around a bit with higher powder charges.

gopherslayer said:

I’m trying to consolidate my powder stock so I don’t have 10 different powders for my rifles. Looking at dumping the Grendel and going 6 ARC and strictly shooting 95gr-108gr. 18-20” barrel.

I would like to believe that factory ammo would be consistent but my experience with Grendel during the last drought was different lots were all over the map accuracy wise so if I go this route I’ll be committed to me doing the loading. I started loading for the Grendel but lost interest in it.

So which powder should I start buying for the ARC?

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I wouldn’t dump Grendel just yet.

Look at the velocity you can get with 90gr TNT or 95gr V-MAX vs the 6mm.

Also, something has been going on with powders I think because data for some of the common ones has changed noticeably. Especially 8208XBR.

I was going to add a 6mm AR all these years and never got around to it, but when I ran the numbers and compared to what I’m seeing with 6.5mm 100gr Hornady ELD-VT, 105gr Sierra Blitzking, and 107gr SMK, they overlap with the 6mm and out-perform it at most of the ranges, given the same barrel lengths.

I used real-world data I’m seeing at 700-1000yds with Grendel, then compared with Hornady’s doppler radar program for the 6mms. That new 100gr ELD-VT load is really flat and they aren’t even pushing it.

N540

Dogtown said:

And when I say "N540 kind of surprised me", shooting ten round strings with a variety of powders loaded nowhere near max, N540 produced noticeably more consistent results (lowest SD/ES and tightest MR). Specifically I was using 26.5gr of N540 with 103 ELD-X and GM205MAR loaded to 2.245" COAL. But it's still kind of slow at 2350fps and might be worth playing around a bit with higher powder charges.

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You might have to turn down the gas a wee bit running N540 near max pressure.

LRRPF52 said:

I wouldn’t dump Grendel just yet.

Also, something has been going on with powders I think because data for some of the common ones has changed noticeably. Especially 8208XBR.

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I was recently considering going ARC over my current Grendel. I'll bite. What's up with 8208 XBR? I decided against ARC just based on the lack of good data for 8208 XBR and 107s (I have 3500 107s on the shelf and about 16 lbs of XBR on hand) and ordered a new Grendel barrel yesterday instead.

JR1200W3 said:

The reason we all end up with so many powders is different barrels like different powders. You should probably get a load sorted and then when you know what shoots best buy more of that.

For Grendel based cartridges you can shoot anyone of:

TAC
8208
4895
Varget
CFE223
LeverRevolution
2520
StaBall

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Which staball?

Staball HD, MATCH, or 6.5?

I need to try LeveRevolution. I was pushing Varget/CFE at max loads (105/107s) that were over pressure in my AR arcs. I had to back the loads off to almost where my Grendel was performing well.

LVR is great for speed, but it's not super temp stable, and the ES numbers can get pretty big.

The weird thing about LVR: it seems to improve SD/ES the closer I get to max. I don't know why, but if I do mild charges between 26-28gr I get pretty big numbers, but when I start to approach 30gr they improve significantly. I may just be an outlier though.

Dogtown said:

The weird thing about LVR: it seems to improve SD/ES the closer I get to max. I don't know why, but if I do mild charges between 26-28gr I get pretty big numbers, but when I start to approach 30gr they improve significantly. I may just be an outlier though.

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Interesting. I used it in a 6.5 Timberwolf (6.5 Dasher basically) back in the day and wasn't anywhere near max. That might explain the wild swings I got.

rothgyr said:

I was recently considering going ARC over my current Grendel. I'll bite. What's up with 8208 XBR? I decided against ARC just based on the lack of good data for 8208 XBR and 107s (I have 3500 107s on the shelf and about 16 lbs of XBR on hand) and ordered a new Grendel barrel yesterday instead.

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Charge weights and velocities from several years ago are different now that Hodgdon’s updated their data for Grendel. They used to have 40 published loads, then went to 170, now 135 for Grendel. Biggest changes were 8208XBR and the addition of CFE223 and LVR, which they didn’t have for years. Hornady was first to publish Grendel data with CFE223 and LVR, which were the fastest powders for 123-129gr.

Their data shows considerably-faster speeds with the same charge weights. Chamber pressures changed a lot too.

90gr TNT on 8208XBR used to be 31.0C max 2794fps at 42,400psi.

Now it’s 31.1gr max at 2992fps at 50,400psi.

That’s an 8,000psi jump at basically the same charge weight, with 200fps more mv.

For H335 under 90gr TNT, their charge weight dropped about a grain, velocity increased 80fps, pressure went up 1,000psi.

I’m not sure if powder formulations deviated during Wuhanflu or what, but there have been noticeable changes.

Another reason why I collect as many sources for reloading data as possible and start at recommended start loads, run pressure ladders over a chrono to see the trend and any departure from the trend.

And another reason to buy one lot and not from several. I'm glad most of my stash is from the same lot, yikes.

rothgyr said:

And another reason to buy one lot and not from several. I'm glad most of my stash is from the same lot, yikes.

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Until you open it and it dries or draws in humidity

<sad_trombone>

I prefer my arc to my grendel. I have also learned to prefer some of the slower ball powders for both of them with heavy bullets. Mp501 which is supposed to be around the 2520 area. Runs pretty close with three good ones. LVR, cfe223, and 2520. In my experience varget and 8208 are tougher on brass and probably tougher on the gun also. Unless it's for light bullets. My 6 arc liked 8208 with the 65 vmax. My gredel likes h335 with the 107smk.

Add AR Comp to your list if you can find it / afford it...

CaptNemo said:

Add AR Comp to your list if you can find it / afford it...

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Is it fast enough?

I also heard a rumor that alliant powders was going to suspend commercial distribution for the foreseeable future. I don't know that I would try to get hooked on meth if meth was going to go away.

Is a powder made for 223 fast enough.
Yes. It is on the little faster than needs to be side even I bet.

supercorndogs said:

Is a powder made for 223 fast enough.
Yes. It is on the little faster than needs to be side even I bet.

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A yes would do. You don't have to be a cunt about it.