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New 6mm Advanced Rifle Cartridge

What Muzzle Devices are guys finding most effective with 6ARC. I have a thread protector for my build I'm assembling today. Suppressor to come. But want a good brake for the interim.
 
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" in stock at Optics Planet"...bahahaha

:unsure: Hmmm, it says "backordered" and "ships in 6-9 months" now, but when I ordered it said "In Stock" and "Ships in 1-3" days or something like that, I think it showed how many were in stock as well. I don't order from them terribly frequently, but I don't recall ordering anything that was labeled as in stock, ready to ship and not getting it in a reasonable amount of time.... Are they known for pulling such shenanigans?

Edit: I also got a "Your item is being prepared for shipment" email this morning so...?
 
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gtscotty
maybe you got lucky and they actually had it in stock, but 8/10 times they aren't truthful with what is actually in stock... used to be ok years ago, but refuse to order from them any more
 
I never bother with different buffer weights, I always just use a standard carbine buffer and adjustable gas block. Makes adjusting for ammo/suppressor/other things on the fly super easy.

That’s my approach now too. There are special cases where I’ll use an extra heavy or light buffer but mostly I use standard carbine or occasionally H1 and tune the gas correctly.

In my observation most of the heavy buffer recommendations are from guys who don’t want to tune the gas system. It’s true that heavy buffers are easier to install than most gas tuning methods, but if you have to experiment it’ll probably cost you more in the long run anyway, and you’re stuck with higher reciprocating weight.
 
Has anyone tried Reloder 17 in the 6mm ARC yet? Playing around with the latest update of QL, it seems that for bullets on the medium heavy to heavy end of the scale, RL17 is often in the top two or three powders for predicted velocity. The compression levels are higher than many of the ball powders, but still seem like something you could reasonably accomplish with a drop tube and a little bit of crunch. QL is off base sometimes, but it has piqued my curiosity about RL17 for this application.

I haven’t tried it because I’m pretty sure you’d have to compress the living crap out of it to get anywhere near the best ball powders. (This kind of prediction is one reason I dislike QL.)

What charge weight is it showing on the top end and for what bullet weight? I do have RL17 and could drop some in a case to see how much compression it would take.

Somebody on another forum said Hodgdon’s 2021 manual has Staball 6.5 data for this too, which seems like totally the wrong powder to me, but I haven’t seen the data. Anyone here see that?
 
I haven’t tried it because I’m pretty sure you’d have to compress the living crap out of it to get anywhere near the best ball powders. (This kind of prediction is one reason I dislike QL.)

What charge weight is it showing on the top end and for what bullet weight? I do have RL17 and could drop some in a case to see how much compression it would take.

Somebody on another forum said Hodgdon’s 2021 manual has Staball 6.5 data for this too, which seems like totally the wrong powder to me, but I haven’t seen the data. Anyone here see that?

What kind of bullets do you have, and what barrel length are you shooting?

Here's the 103gr ELDx @2.26" out of a 20" tube. 103% is not what I would call "compressing the living crap out of it" just a little crunch.

1610229594017.png


108gr ELD @ 2.26" - Crunchier
1610229885247.png


95gr BT @ 2.26" - Crunchiest
1610230124309.png


QL estimates that some of my crunchier .308 Varget loads have had fill ratios quite a bit higher, if their density numbers for RL17 are accurate all of these should be do-able. I have some left over RL17 from a ways back, I'll certainly be giving it a try once all my parts get here, I was just curious if anyone had taken a crack at it to date.

StaBall is in the newest QL update, but the program estimates with it look screwed up compared to Hodgdons load data, which IME is usually reasonably accurate.
 
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What kind of bullets do you have, and what barrel length are you shooting?

Here's the 103gr ELDx @2.26" out of a 20" tube. 103% is not what I would call "compressing the living crap out of it" just a little crunch.

View attachment 7524061

108gr ELD @ 2.26" - Crunchier
View attachment 7524067

95gr BT @ 2.26" - Crunchiest
View attachment 7524074

QL estimates that some of my crunchier .308 Varget loads have had fill ratios quite a bit higher, if their density numbers for RL17 are accurate all of these should be do-able. I have some left over RL17 from a ways back, I'll certainly be giving it a try once all my parts get here, I was just curious if anyone had taken a crack at it to date.

StaBall is in the newest QL update, but the program estimates with it look screwed up compared to Hodgdons load data, which IME is usually reasonably accurate.
FYI- StaBall 6.5 in my first tests actually has lower velocity than the Quickload predictions, different yet similar cartridge. The Hodgdon data seems "optimistic".
 
This is a random question

I have about 80 brass casings of once shot factory Hornady eld match 6mm arc, is it sellable on the forum here
 
This is a random question

I have about 80 brass casings of once shot factory Hornady eld match 6mm arc, is it sellable on the forum here

Once you get 100 (useful... don't go spamming to get 100 posts or the mods will yank your account) posts the 'for sale' section of the forum opens up and you can post in there.
 
Once you get 100 (useful... don't go spamming to get 100 posts or the mods will yank your account) posts the 'for sale' section of the forum opens up and you can post in there.
Thanks, ill probably just pay to be a member as I'm on this forum way too much anyways
 
FYI- StaBall 6.5 in my first tests actually has lower velocity than the Quickload predictions, different yet similar cartridge. The Hodgdon data seems "optimistic".

Interesting, what cartridge were you loading it in? I've only used it in .30-06, and it has done well velocity-wise with a few different bullet weights, but I've read posts by plenty of folks that seem to be happy with it in 6mm GT, 6.5 CM, and 7mm-08.

That said, I think it's probably too bulky for best velocity in 6mm ARC, I've always heard that compressing ball powder can get peakier, quicker than most extruded. The StaBall ARC data on the Hodgdon site is compression limited and fairly anemic:

103gr VTAC - 30.7C gr @ 2,611 fps
107gr Sierra hpbt - 30.0C gr @ 2,557 fps
110gr A-Tip - 30.3C gr @ 2,555 fps

That's from a 24" barrel, they have a few different powders that are faster, and CFE 223 is much faster.
 
I have a question for all of you that already have setups going.

I have read on several threads that people have successfully used standard pmags (although they weren't using standard capacity 30 round mags) and they worked just fine. I am wondering if anyone has tried using standard 20 round (or 10 round) mags for 6 ARC?

If you have experimented around with that in any way please help me cut the chase as to what makes them not compatible with a standard mag.

I am pretty sure I will need to buy mags eventually, but that plan might get moved up rather quickly in the coming weeks. If you know which brands of mags are good to go please let me know.

---
On a side note I bought a stripped upper and a handguard today that will eventually become my 6ARC build. What I wanted (matching set to my lowers) finally came back in stock and I was the first in line.

I've read a TON about the differences between type 1 and type 2 bolts so I think I am good there. I just need to settle on a barrel (and a barrel length) next. I have several complete BCG for 5.56 as back ups, so I think once I decide on a barrel I will buy a couple of bolts and use the carrier(s) I already have.

I will go back and re-read this whole thread just to refresh myself on the latest news.
 
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My ASC mags haven’t had any issues and they are cheap ($13 something at primary arms) so I would just buy some instead of trying to use something else not made for it.
Same, I've been using ASCs with no feeding problems, except one of the 15 rounders in my Grendel doesn't lock on empty sometimes. Also bought some of the new Duramags that are supposed to be good. I tried using both my PRI 6.8 waffle mag, and Pmag 20 rounders with a Grendel specific 3d printed follower and neither of them worked for me.
 
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My ASC mags haven’t had any issues and they are cheap ($13 something at primary arms) so I would just buy some instead of trying to use something else not made for it.
With those mags, can you tell me with the 15 and 25 round mags if it hinders movement from a bipod (IE the mag hitting the ground)?

I would like to get as much capacity as possible while still not having an issue with a mag that's too long for my intended use.
 
Since I just ordered my parts today and still need more parts before I can complete my build I am somewhat hesitant to put all my eggs in one basket when it comes to mags of one flavor. Ideally I would be able to test a given variety of mag before stacking them deep. I guess I am kind of antsy due to the political situation.
 
ASC 15 rounders here as well. No problems.

E-lander 25's work if I don't run suppressed, but the fouling from a suppressor causes them to gum up and the bolt outruns the magazine. The 25 rounders of any flavor have the same issues as 30 round 5.56 mags as far as height and bipods go. I run 15's almost exclusively anymore, and 20 rounders for 5.56/300 b/o for that reason.
 
ASC 15 rounders here as well. No problems.

E-lander 25's work if I don't run suppressed, but the fouling from a suppressor causes them to gum up and the bolt outruns the magazine. The 25 rounders of any flavor have the same issues as 30 round 5.56 mags as far as height and bipods go. I run 15's almost exclusively anymore, and 20 rounders for 5.56/300 b/o for that reason.
The height issue is the main thing. 15 rounders seem like they would be good to go for my purposes.

If you have a 15 rounder laying around if you could measure the OAL that would be awesome. I want to see how long they are compared to a 20 round PMag.

I would be comfortable starting to stack those up (15 rounders).

As for suppressed, I shoot suppressed all the time. I have never had an issue with 30 round mags gumming up. 300BLK or 5.56.... anyway stacking a bunch of 15 rounders would be ok. I saw some mags that are 20 rounders as well. That's kind of in the middle as to clearance for shooting from a bipod and/or bags.
 
The tapered jacket is the significant difference with the ELDX. From my own testing of the ELDX and Interlock bullets in a few different calibers, I’m not convinced the interlock ring actually does much, if anything, but the tapered jacket goes a long way to limiting expansion. It’s possible the lead core may be a harder alloy too, some manufacturers do that but I’m not sure about the ELDX in particular. That can also have a big effect.
Thanks Yondering.

Along the same lines, does anyone have an idea how the Hornady Black and TAP loads compare to the ELD-M and -X loads for accuracy and possible hunting?

Hell, are the TAP rounds even in existence yet? I’m on a couple of waiting lists but no joy.
 
With those mags, can you tell me with the 15 and 25 round mags if it hinders movement from a bipod (IE the mag hitting the ground)?

I would like to get as much capacity as possible while still not having an issue with a mag that's too long for my intended use.

I can tell you the 15 rounders don't hinder it at all. I didn't buy any 25rd mags because I didn't figure I would ever have a use for them with what my plans are for my ARC.
 
On ARFCOM someone mentioned they the new ASC ARC specific red follower mags seem to have a different profile and present the round higher than the blue follower Grendel mags. From the pics he posted, it looks to me like the ARC mags just have more cutout in the feeding area in the front of the mag well, and that the follower height would actually be about the same. Does anyone have both so they could confirm?
 
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I just bought three of these mags. That was the limit they would let me purchase. It says it's 6ARC specific. Tell me what you guys think. Someone said these are simply ASC mags with a different label on them. It's kind of hard to tell what's going to work since I have no way to actually confirm function yet.

Edit: I wanted to add that I went ahead and bought a few mags because I didn't want to get caught with my pants down later on if the you know whos' decide to pull something crazy.

 
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I just bought three of these mags. That was the limit they would let me purchase. It says it's 6ARC specific. Tell me what you guys think. Someone said these are simply ASC mags with a different label on them. It's kind of hard to tell what's going to work since I have no way to actually confirm function yet.

Edit: I wanted to add that I went ahead and bought a few mags because I didn't want to get caught with my pants down later on if the you know whos' decide to pull something crazy.

The AR-Stoner Grendel mags are ASC mags, and it looks like these are too, you can read the "A" and "C" of "ASC" embossed on the top of the follower in the second product photo.
 
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The AR-Stoner Grendel mags are ASC mags, and it looks like these are too, you can read the "A" and "C" of "ASC" embossed on the top of the follower in the second product photo.
I am guessing that's saying it's GTG.

I actually called ASC and asked their technician on the phone what the differences were and he specifically said that red followers were for 6ARC, blue 6.5 grendel.

If these are being sold as 6ARC compatible and with the reviews I've seen from many (including here) I am confident stacking these up.
 
I am guessing that's saying it's GTG.

I actually called ASC and asked their technician on the phone what the differences were and he specifically said that red followers were for 6ARC, blue 6.5 grendel.

If these are being sold as 6ARC compatible and with the reviews I've seen from many (including here) I am confident stacking these up.
...did the ASC Tech by any chance say what the differences were between the followers other than color or is that all it is, a color change?
 
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I bought 30+ magazines last year and didn't spend more than 48 cumulative seconds thinking about it, much less several minutes writing about it and making phone calls.
 
I bought 30+ magazines last year and didn't spend more than 48 cumulative seconds thinking about it, much less several minutes writing about it and making phone calls.
So do you want a reward or something?

I will go see if we have any cookies that I can give you.
 
Just pointing out that the endless mental masturbation is a lot more difficult than just ordering a few magazines.
 
Just pointing out that the endless mental masturbation is a lot more difficult than just ordering a few magazines.
Well if we were talking 5.56 that's one thing, but even there you have tons of mags that are less than optimal.

However since this is a relatively new thing, and there are a metric crapton of people reporting mag issues with various setups (that were originally intended for the Grendel cousin), it's worth discussion. And now throw into the mix that apparently at least one company is now making mags that are specific to the caliber, so that to me is worth knowing before blowing cash on something that may or may not actually function.

I measure twice and cut once, or try to. If you don't do that, that's fine. It's your money. But as for me I am trying to not reinvent the wheel here and learning from other people's experience.

It's really no different than an experience I had at a local store. A guy when to check out with a whole basket full of 9mm Makarov for his new Glock. The cashier said, "Are you sure?" His response, "It says 9mm on the box don't it?!" She then said "Fine. It's your money, but we don't do refunds on ammo. "
 
But its not a new thing. If a bunch of magazines have worked perfect with 6.5 Grendel for years, and then those same magazines have worked perfect when said 6.5 is necked down to 6mm, those same magazines should work perfect when that 6mm cartridge has its shoulder shortened a tiny bit. Any company that says a newfangled follower can somehow recognize a .030" shoulder difference is selling you a bridge.

Your analogy would be closer if the Glock said 9mm Parabellum on the side and the customer wouldn't buy ammo labeled 9x19.
 
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Little bit of an update from me: finally getting my 6ARC out on TARGETS! Settling on a 105gr Berger Hybrid over 29.3grs of Lever (thanks @Yondering for your range reports on this load). Its doing a hair under 2700fps from my 20" AR at 35-45*F, v nice SD/ES and precision. We will see how it does as temp changes.

Obviously, 2700fps from a 0.53ish G1 BC bullet ain't outperforming typical bolt gun loads from long barrels, but it is still massive step up over a 5.56mm AR and a good bump over a 6.5G (I was getting 2450fps-ish w/ a 123gr there).

I'm seeing this in the range reports: over the 30 or so targets I have deployed on my farm, I'm making good hit % on most of them, about what the stats would say (its not close to my 6x47 w/ a 105gr doing 3050fps).

Do I love this cartridge/gun? No, but I like it.
Will I use this cartridge/gun? Yes, both in the informal 'buddy matches' I do and for varmint control.
Would I recommend it to a buddy? Yes, depending on their objectives.
Would I do anything different? Outside of the short-stroking I had, nothing major. I should have gone to Lever quicker, as I was screwing around w/ extruded powders too long, despite advice on here and my experience loading 6.5G.
 
Little bit of an update from me: finally getting my 6ARC out on TARGETS! Settling on a 105gr Berger Hybrid over 29.3grs of Lever (thanks @Yondering for your range reports on this load). Its doing a hair under 2700fps from my 20" AR at 35-45*F, v nice SD/ES and precision. We will see how it does as temp changes.

Obviously, 2700fps from a 0.53ish G1 BC bullet ain't outperforming typical bolt gun loads from long barrels, but it is still massive step up over a 5.56mm AR and a good bump over a 6.5G (I was getting 2450fps-ish w/ a 123gr there).

I'm seeing this in the range reports: over the 30 or so targets I have deployed on my farm, I'm making good hit % on most of them, about what the stats would say (its not close to my 6x47 w/ a 105gr doing 3050fps).

Do I love this cartridge/gun? No, but I like it.
Will I use this cartridge/gun? Yes, both in the informal 'buddy matches' I do and for varmint control.
Would I recommend it to a buddy? Yes, depending on their objectives.
Would I do anything different? Outside of the short-stroking I had, nothing major. I should have gone to Lever quicker, as I was screwing around w/ extruded powders too long, despite advice on here and my experience loading 6.5G.
Awesome, glad to hear it’s working so well.

One thought, and this is partly personal bent and partly experience - there’s probably another 60-100 fps left to go in that load, and in all three of my barrels with 105s Lever shoots best turned up to max (meaning max for good case life, still getting ~10 loads per case with Lapua) once I dialed in on the optimum seating depth.

Of course your current load will probably do exactly that in the summer, from what I’ve seen.
 
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But its not a new thing. If a bunch of magazines have worked perfect with 6.5 Grendel for years, and then those same magazines have worked perfect when said 6.5 is necked down to 6mm, those same magazines should work perfect when that 6mm cartridge has its shoulder shortened a tiny bit. Any company that says a newfangled follower can somehow recognize a .030" shoulder difference is selling you a bridge.

Your analogy would be closer if the Glock said 9mm Parabellum on the side and the customer wouldn't buy ammo labeled 9x19.
Exactly. The people who think this is really something new need to do a little research. All Hornady did was change it just enough to be proprietary and then do pressure testing and sell factory ammo. I know that’s a simplification but that’s about all that affects us.

Most magazine issues I’m hearing about come back to either a poorly tuned gas system, or doofuses using 5.56 mags.

Edit - to add to this, if you wouldn’t use 9mm mags for your 40 S&W pistol (hopefully most here are smart enough not to), then why use 5.56 mags for a Grendel or ARC case? The difference from 5.56 is greater than 9mm from 40.
 
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What kind of bullets do you have, and what barrel length are you shooting?

Here's the 103gr ELDx @2.26" out of a 20" tube. 103% is not what I would call "compressing the living crap out of it" just a little crunch.

View attachment 7524061

108gr ELD @ 2.26" - Crunchier
View attachment 7524067

95gr BT @ 2.26" - Crunchiest
View attachment 7524074

QL estimates that some of my crunchier .308 Varget loads have had fill ratios quite a bit higher, if their density numbers for RL17 are accurate all of these should be do-able. I have some left over RL17 from a ways back, I'll certainly be giving it a try once all my parts get here, I was just curious if anyone had taken a crack at it to date.

StaBall is in the newest QL update, but the program estimates with it look screwed up compared to Hodgdons load data, which IME is usually reasonably accurate.
I tried that RL17 load in my 19” with the 105 BTHP (which Hornady lumps into the same data as the 103gr). You’re right about the compression; a full case held around 34gr which surprised me.

When I got up to 30.8gr, velocity was 2660 fps; not too slow but not great. However there was a significant extractor imprint on the Lapua brass, so it’s clearly way over max ARC/Grendel pressure and I didn’t fire any more.

RL17 has a reputation for spiking hard when it hits max. It’s also fairly sensitive to temperature, so I don’t see much advantage to it in this application. However it does make me wonder about RL16, which is fairly temp stable and is a better substitute for RL17 in the Creedmoor. Maybe worth looking into.

In comparison, my Lever load does 2780 fps from the same barrel with excellent case life, and Lever seems to be a lot more forgiving as you push up to max

This is what I’m talking about with QL predictions. As a tool to generate thought and try new possibilities it’s great, but it’s ranking of which powders deliver best velocity seems to leave a lot to be desired.

StaBall has been absolutely garbage in my 6.5 Creedmoor. Maybe some batches are better than others? Mine is giving velocity 200-300 fps slower than advertised from the same barrel length (no pressure signs) and even pushing a couple grains over listed max doesn’t get it there but gives ES of around 100 fps. Something isn’t right there.
 
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Little bit of an update from me: finally getting my 6ARC out on TARGETS! Settling on a 105gr Berger Hybrid over 29.3grs of Lever (thanks @Yondering for your range reports on this load). Its doing a hair under 2700fps from my 20" AR at 35-45*F, v nice SD/ES and precision. We will see how it does as temp changes.

Obviously, 2700fps from a 0.53ish G1 BC bullet ain't outperforming typical bolt gun loads from long barrels, but it is still massive step up over a 5.56mm AR and a good bump over a 6.5G (I was getting 2450fps-ish w/ a 123gr there).

I'm seeing this in the range reports: over the 30 or so targets I have deployed on my farm, I'm making good hit % on most of them, about what the stats would say (its not close to my 6x47 w/ a 105gr doing 3050fps).

Do I love this cartridge/gun? No, but I like it.
Will I use this cartridge/gun? Yes, both in the informal 'buddy matches' I do and for varmint control.
Would I recommend it to a buddy? Yes, depending on their objectives.
Would I do anything different? Outside of the short-stroking I had, nothing major. I should have gone to Lever quicker, as I was screwing around w/ extruded powders too long, despite advice on here and my experience loading 6.5G.
Glad you got things worked out.
What primers and brass are you using by chance?

I have some Sta-ball and RL16 saved for CM.
 
what is the brass life of this 6mmARC compared to 224V from an AR?
So far I’ve got 5 loads out of a piece of hornady brass. no cracking or signs of failure yet. Loading leveRution powder under 105 Berger’s and I’ve loaded some 108 eld’s. Dirty dirty powder But best velocities. Still tuning but I’ve run up as high as 25.6gr I think. Data is in the shop. I can reply later with approximate data
 
So far I’ve got 5 loads out of a piece of hornady brass. no cracking or signs of failure yet. Loading leveRution powder under 105 Berger’s and I’ve loaded some 108 eld’s. Dirty dirty powder But best velocities. Still tuning but I’ve run up as high as 25.6gr I think. Data is in the shop. I can reply later with approximate data
Looks like you're running really light loads, Hornady's max for 108gr/110gr with LVR is 29.7gr, and Hodgdon's max is 28.2gr. Light loads might be why it is so dirty. I've been looking for LVR for a month or so, but it's long gone around here.
 
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Looks like you're running really light loads, Hornady's max for 108gr/110gr with LVR is 29.7gr, and Hodgdon's max is 28.2gr. Light loads might be why it is so dirty. I've been looking for LVR for a month or so, but it's long gone around here.
I am wrong. I shouldn’t have included the data. Im not in front of my info. i tried to recall it but I do know I went beyond hornady‘s max. Also this is from a 24“ bolt gun. Not gas. Uintah Precision complete upper
 
My Odin Works barrel and Aero BCG came in, but the muzzle end of the barrel looks a bit gonzo... There is some kind of unevenely ground area at the muzzle, the bore is noticeably off-center in the crown, and there's no undercut between the threads and the shoulder.
IMG_20210116_105619760~01.jpg

IMG_20210116_110921312~01.jpg

IMG_20210116_110902716~01.jpg


Has anyone elses Odin barrel looked like this? I want to mount up and go shoot, but I think I probably ought to call them up and get it fixed first.... Don't need an extra hole in any of my cans.
 
I'm glad you posted this. I'm shopping for a barrel now. Keep us posted on how they handle it.
 
Speaking as a machinist who turns his own barrels:

The lack of undercut at the shoulder is normal, that centers a crush washer if you use one. Some barrels have that and some don’t; it just depends on the method used to thread it.

Looks like they cut the crown off-center and also forgot to deburr or chamfer it. Not impressive at all, but maybe it was just a bad one that slipped through in a time when companies are rushing to get stuff out the door. I’d ask them to make it right, if it were mine.
 
In regards to 18” barrels, what is the preferred gas length now that you guys have had some time shooting them? Standard rifle or a rifle +1”? This would be primarily suppressed.
 
Take calipers and measure thread OD to groove on opposite sides of the barrel and see if the bore is off center in the threads or if they just ran the crown recess off center.