New 6mm Advanced Rifle Cartridge

[tomcatfan]

Am I the only one who hopes those pressures and velocities are a little conservative?

I remember when I first started reloading I got all excited and loaded up 200 rds of 9mm ammo based on the middle of the charge weight in my Hornady manual based on my components. I went to the range, and the rounds were so light in charge that they wouldn’t cycle my M9 at all. I learned a valuable lesson that day on load development.

 

[steve podleski]

Hornady is giving away FREE 6mmARC data for their 108 and 110s, so I am taking the liberty of posting here. (Posted originally on the 6mmARC.com forum.)

View attachment 7368198

Don't see any load data and barrel length that gives the advertised 2750fps.

 

[7mmShooter]

2740fps with LVR or CFE223 Max Charge in a 24". Close enough, barrel to barrel will vary more than that anyway

 

[steve podleski]

2740fps with LVR or CFE223 Max Charge in a 24". Close enough, barrel to barrel will vary more than that anyway

True. I missed that! Good to see it.

I've noticed with LeveRevolution that there is more gas in the gas tube by the recoil of the BCG.

 

[Gtscotty]

Am I the only one who hopes those pressures and velocities are a little conservative?

No I'm there with you, from the load data, with temp in-sensitive powders it basically gives the same velocities with 108gr ELDs as a grendel does with temp in-sensitive powders and 123gr ELDs. An extra 0.015 G7 bump, but that seems to be about it, I was hoping for better velocities without having to resort to known temp sensitive options like LVR and CFE223. The A-Tips have better BCs, but I'm not realistically going to spring for A-Tips to run through a gas gun, maybe some folks will.

I'd also be interested to see data with lighter bullets as well, 105s through 95s could be useful.

I do wonder if Hornady is using a ball or extruded powder in their factory loads, they seem to be faster than any of the load data they supplied.

 

[ormandj]

No I'm there with you, from the load data, with temp in-sensitive powders it basically gives the same velocities with 108gr ELDs as a grendel does with temp in-sensitive powders and 123gr ELDs. An extra 0.015 G7 bump, but that seems to be about it, I was hoping for better velocities without having to resort to known temp sensitive options like LVR and CFE223. The A-Tips have better BCs, but I'm not realistically going to spring for A-Tips to run through a gas gun, maybe some folks will.

I'd also be interested to see data with lighter bullets as well, 105s through 95s could be useful.

I do wonder if Hornady is using a ball or extruded powder in their factory loads
, they seem to be faster than any of the load data they supplied.

I wonder if a new powder might be in the works. There’s a pretty big gap with the temperature insensitive stuff in this burn rate. Also reading about the sensitivity, I don’t see any real numbers. Maybe it’s not that bad, I’ll have to chronograph. Since the pressure curves are not linear with temperature, it may be a non-issue at the temperatures I shoot.

I know it's something most of us are spoiled past doing, but it's easy enough to track velocity vs. temperature and correct/extrapolate accordingly.

I don’t know about you, but memorizing a dope chart for 100m-1000m is about the limit for me. Trying to do it for multiple temperature increments is another level. I don’t like to constantly be on my phone or looking at cards to shoot at distance. I guess I can remember offsets based on temperature changes. Just another variable to mess with my groups!

Thoughts on CFE223 vs. LVR? I like the idea of not worrying about copper fouling but not if it’s at the expense of accuracy, temperature, or pressure sensitivity. I’ve never touched either of these two powders, but looks like I’ll be picking some up.

 

[Gtscotty]

FWIW, it's available in the Hornady Reloading application on your phone, you just select the free load data. It may not be there forever, though, so good to take a screenshot if you need to save it locally.

It's also available in .pdf form on the website for those who don't want to mess with the app.

Temporary Hornady Load Data

 

[lennyo3034]

I plan to try 110 SMKs in this. Little better BC than 110 ATIP. Less consistent accuracy but I’m not going for absolute accuracy in a gas gun. Good bit cheaper than ATIPs too.

 

[Ledzep]

I don’t know about you, but memorizing a dope chart for 100m-1000m is about the limit for me. Trying to do it for multiple temperature increments is another level. I don’t like to constantly be on my phone or looking at cards to shoot at distance. I guess I can remember offsets based on temperature changes. Just another variable to mess with my groups!

Thoughts on CFE223 vs. LVR? I like the idea of not worrying about copper fouling but not if it’s at the expense of accuracy, temperature, or pressure sensitivity. I’ve never touched either of these two powders, but looks like I’ll be picking some up.

0-600 usually (play with the numbers on jbm and verify) you can create a cheat sheet or dope card that will work basically within a click. Anything past 500-600 I'm using a Kestrel and/or phone app that's going to require temp input. If you figure X fps per 20 degrees from a baseline it's pretty quick and easy.

 

[ormandj]

Spoke to Hodgdon, they suggested that CFE223/Leverevolution will have the same temperature stability. I'll just buy some LVR based on case fill and other's experience here.

 

[jbailey]

I don’t know about you, but memorizing a dope chart for 100m-1000m is about the limit for me. Trying to do it for multiple temperature increments is another level. I don’t like to constantly be on my phone or looking at cards to shoot at distance. I guess I can remember offsets based on temperature changes. Just another variable to mess with my groups!

@ormandj, not that I want to spend anymore of your money (we all buy too much gear, right?!?!), but I will say the temp curve feature on the Kestrel AB is amazing. What you do is shot the load in as many temps as you can, 20*F, 55*F, 85*F, etc, and plug those temps and MVs into the Kestrel. Kestrel will then model the MV curve. I have found these resulting curves are very accurate (+/- 2 or 3 fps). I have used 2000MR in a 308 for years with this feature and it has consistently produced good results (and this out out to very long ranges for a 308).

RE the temp sensitive powders. I remember this same game with the 6.5G. Win 748, BLC2, 2520, ball powders where you stuff the case, trying to move the 123 to a speed that produces a less than rainbow drop chart. In the end, I moved down to a 107gr 6.5mm SMK and had great results.

I'm looking to do the same game plan with the 6ARC. I'm going to see what 95gr SMK, the 95gr Berger Classic Hunter, and the Flatline 88gr and 95gr will all do. Looking for 2900fps or faster from 20" AR, as a farm gun out to 800yds or so. Yotes and ground hogs are on notice!

 

[steve123]

I can tell you from experience that when I tried AA2520(temp sensitive) in my 6mmART40, with a load worked up in summer and then shot in winter, that I thought my scope was broke, and that was only 600Y.
Since my goal is always a 1st round hit, I swore off extra velocity in favor of temp stability from then on.
6 ARC is a little cartridge - don't try to make it what it isn't, in fact don't do that with any cartridge, which was my lesson learned the hard/expensive way.

 

[ormandj]

@ormandj, not that I want to spend anymore of your money (we all buy too much gear, right?!?!), but I will say the temp curve feature on the Kestrel AB is amazing. What you do is shot the load in as many temps as you can, 20*F, 55*F, 85*F, etc, and plug those temps and MVs into the Kestrel. Kestrel will then model the MV curve. I have found these resulting curves are very accurate (+/- 2 or 3 fps). I have used 2000MR in a 308 for years with this feature and it has consistently produced good results (and this out out to very long ranges for a 308).

RE the temp sensitive powders. I remember this same game with the 6.5G. Win 748, BLC2, 2520, ball powders where you stuff the case, trying to move the 123 to a speed that produces a less than rainbow drop chart. In the end, I moved down to a 107gr 6.5mm SMK and had great results.

I'm looking to do the same game plan with the 6ARC. I'm going to see what 95gr SMK, the 95gr Berger Classic Hunter, and the Flatline 88gr and 95gr will all do. Looking for 2900fps or faster from 20" AR, as a farm gun out to 800yds or so. Yotes and ground hogs are on notice!

I've already got one (4DOF model) that pairs with my Leica RF and provides firing solutions. I just like shooting from memory/milling for ranging more, when possible. I'll see if the 4DOF version can do the temperature curve, I believe it has modeling for powder temperature/pressure curves, so should achieve the same end result. Thanks for the tips, I guess I'll just have to move out of the stone age and carry a few extra batteries and devices with me. At least they are small!

 

[janttony]

I do wonder if Hornady is using a ball or extruded powder in their factory loads, they seem to be faster than any of the load data they supplied.

I’ve been wondering about this myself. Or some of that magical Superformance powder they’re known for.

 

[awpk03s]

Still anxiously awaiting my 20” CMMG upper, 3 weeks in. I’ve got some Hornady Black ammo ready to go, and a good stash of CFE 223 for whenever I get some dies in hand.

 

[NH4X]

Still anxiously awaiting my 20” CMMG upper, 3 weeks in. I’ve got some Hornady Black ammo ready to go, and a good stash of CFE 223 for whenever I get some dies in hand.

Im interested to see how cfe223 does in this round.......please post results when you have data......im thinkin it might be on the slow side of burn rate. But who knows, it might work ok.
Edit: just saw hornadays reload data......cfe223 may be the go to powder.....even tho its sensitive to temp.

 

[Ledzep]

CFE223 shot best vs. LVR and AA 2520 with 103 ELD-X's in my CZ527 Bolt gun. Understand this is a little bit over the 52,000 PSI gas gun limit, but with 30.0gr I'm at 2707fps in an 18" barrel and it shot 10 shots at 1.6" at 200yd.

ETA: AA2520 was similar in the 6 ARC to how I remember it in the 6.5 Grendel. Everything is great and then pressure lays on quick. Not a real steady progression from everything being okay to extreme primer flow into the FP hole.

 

[awpk03s]

I’m planning CFE 223 just based on what’s I’ve read in this thread, and the Hornady published data.... and I’ve got a real burner load worked up for 64gr bonded soft points in .223, so it’s available in my stash already haha.

I have not experienced the temp instability personally as of yet, but I also haven’t shot it a great deal - and I did load workup in the summer heat to begin with.

 

[MichiganMitten]

Is there an app or program that allows reloaders to estimate the barrel pressures for various powders and different grain bullets?

 

[Silverjay]

Quickload

 

[alamo5000]

I have 16 unopened pounds of CFE 223. Now I just need a 6mm ARC and some brass. It would be pretty nice to have just one powder (more or less) for my 5.56 SBR (and potentially the 6 ARC.) That said stocking more than one powder is the least of my concerns provided there is decent availability of whatever I settle on... Stuff like Retumbo (obviously for a different cartridge all together) is forever out of stock with no ETA. I assume this is because of supply line issues but who knows.

There are several powders that fall around the same burn rate but according to the Hornady load data that was published several of them despite similar burn rates still don't give the same results as CFE223. I am not expert enough to know the subtle nuances in powder characteristics to tell you why this is so.

That said if 6ARC takes off I think we will see a few more options for powder pop up. Also once they get out into the wild more people will try different powders. I am definitely curious. N133 is near in burn rate but who knows if it will produce velocity results in this cartridge.

 

[alamo5000]

Don't see any load data and barrel length that gives the advertised 2750fps.

They have 2740 FPS listed and that is more than within the margin of error for temperature (as well as barrel) differences day to day. If it's 80 degrees one day and 60 degrees the next you typically will be able to see small velocity variations even with the best powders.

I found this quote regarding Varget (hear me out)... but I mentioned that because it's known as a very temperature stable powder.

"Hodgdon Varget was the second least temperature sensitive powder in this test, with 46 fps of variance in muzzle velocity between temperatures of 25° F and 140° F."

Source:

Powder Temp Stability: Hodgdon Extreme vs. IMR Enduron

The goal of this field test was to quantify the temperature stability of the popular Hodgdon H4350 a...

precisionrifleblog.com

I should also add that this cartridge is for both bolt guns and gas guns. Bolt guns per Hornady's info and load data says bolt guns have different published load data than gas guns.

 

[ormandj]

Did anybody ever get an H2O/capacity measurement on a fired case? I've modeled the case in gordon's reloading tools, now I just need an accurate measure of case capacity (fired). Also, did anyone else notice that the case diameter at the base is improperly converted into metric on the SAAMI drawing? .441" is not 10.44mm.

 

[Raufoss]

Anyone have any guesses of what kind of velocities the 6mm ARC might be able to achieve with hand loads and a 26" barrel in a bolt gun? Wondering just how close it might be able to get to a Dasher.

Well case capacity is 39gr so I am pretty sure 2850/2880 fps ish is total achievable with 105’s.

 

[MPrimo]

Took the plunge ... Ordered a Craddock barrel and bolt. Have everything else ... waiting ...

Not everything ... scope??? NX8 maybe? Suggestions ...

 

[alamo5000]

Anyone have any guesses of what kind of velocities the 6mm ARC might be able to achieve with hand loads and a 26" barrel in a bolt gun? Wondering just how close it might be able to get to a Dasher.

On the gas gun side it lists 2785 fps out of a 26" barrel for 108-110 projectiles. I would think it's safe to assume even faster velocities out of a bolt gun.

That's around 150 to 200 fps shy of what you get out of a Dasher with a 26" barrel. If Raufoss is correct in his estimate that will put the 6 ARC within 100 fps as a 6 Dasher out of the same length barrel.

" Of the guys that were loading in that very popular band (32.3-32.5gr of Varget) and running the popular 105gr Hybrid from a 26” barrel, they reported average muzzle velocities from 2925-2975 fps."

Source:

6mm Dasher Load Data – What The Pros Use

I’m really excited about the next few articles! Each year I survey the top-ranked precision rifle s...

precisionrifleblog.com

 

[Constructor]

On the gas gun side it lists 2785 fps out of a 26" barrel for 108-110 projectiles. I would think it's safe to assume even faster velocities out of a bolt gun.

That's around 150 to 200 fps shy of what you get out of a Dasher with a 26" barrel. If Raufoss is correct in his estimate that will put the 6 ARC within 100 fps as a 6 Dasher out of the same length barrel.

" Of the guys that were loading in that very popular band (32.3-32.5gr of Varget) and running the popular 105gr Hybrid from a 26” barrel, they reported average muzzle velocities from 2925-2975 fps."

Source:

6mm Dasher Load Data – What The Pros Use

I’m really excited about the next few articles! Each year I survey the top-ranked precision rifle s...

precisionrifleblog.com

A Dasher will push a 95smk to 3200 out of a 22" barrel using N550, a 105 to 3050.

 

[alamo5000]

A Dasher will push a 95smk to 3200 out of a 22" barrel using N550, a 105 to 3050.

I'm pretty sure it's possible and I was about 95% confident that someone would question the data so I put the source of my data up for the specific barrel length quoted.

 

[Constructor]

I'm pretty sure it's possible and I was about 95% confident that someone would question the data so I put the source of my data up for the specific barrel length quoted.

What I posted was out of a gas gun too not a bolt.

 

[ormandj]

Well case capacity is 39gr so I am pretty sure 2850/2880 fps ish is total achievable with 105’s.

I thought 6mmBR was 39gr H2O capacity, are you sure that's correct for 6mm ARC? That seems higher than I'd expect - I'm hoping someone has measured.

 

[Ledzep]

I measured 33.8 and someone else had 34.5 on ar15.com

 

[jbailey]

for the guys that are reloading 6ARC-
WOULD YOU MIND SHARING YOUR BRASS AND DIES TYPE AND SOURCE?
Are you necking down 6.5G brass? Will that work without other mods?

thanks much!

 

[ormandj]

for the guys that are reloading 6ARC-
WOULD YOU MIND SHARING YOUR BRASS AND DIES TYPE AND SOURCE?
Are you necking down 6.5G brass? Will that work without other mods?

thanks much!

Dies are the Hornady dies (from Midway USA) - I had back-ordered it when it first came up for purchase, brass is from fired 108gr ELD-M Hornady 6mm ARC loaded ammo. They sell the brass by itself, too.

I've called the major players in the reloading world (Forster/LE Wilson/Giraud/AMP/etc) and they are all planning things, Giraud had a working solution for now, AMP just wanted some fired cases, etc - so more options should start showing up soon.

 

[awpk03s]

Midway USA has RCBS small base die sets available for 6mm ARC.

 

[trdjohn]

MidSouth posted pic hornady ARC dies they got in stock, mine has been on back order since mid June, but got email saying it'll ship soon

originally put order for BA barrel, but dropped that and changed to 18" odin, that was mid June too, supposedly the next batch will be finished soon, and I should be in that group...anyone got their odin barrel yet, how's it shoot, how's the gas system run, how's the chamber?

 

[Yondering]

I’ve been wondering about this myself. Or some of that magical Superformance powder they’re known for.

Definitely not commercial Superformance, the burn rate is way too slow. If they're using a ball powder, based on their own data it'd have to be something very similar to Lever, but probably not a commercial grade you can buy.

CFE223 shot best vs. LVR and AA 2520 with 103 ELD-X's in my CZ527 Bolt gun. Understand this is a little bit over the 52,000 PSI gas gun limit, but with 30.0gr I'm at 2707fps in an 18" barrel and it shot 10 shots at 1.6" at 200yd.

In 243 LBC, CFE223 worked really well for me with the 95gr VLD. However, in the heavier weights, particularly with the 105gr BTHP, Lever shoots significantly better in my rifles. Both are capable of similar velocity, but Lever is more accurate and has a very wide accuracy node right up at max.

for the guys that are reloading 6ARC-
WOULD YOU MIND SHARING YOUR BRASS AND DIES TYPE AND SOURCE?
Are you necking down 6.5G brass? Will that work without other mods?

thanks much!

It's more than just a neck down, you have to push the shoulder back too, about .030". It's not a big deal, but does leave the potential for a donut at the base of the neck. (That's partly why most of the 6mm Grendel-based wildcats were just a simple neck down, like the 243 LBC I use.)
Lapua brass is awesome of course and readily available in 6.5 Grendel, but not sure when or if you'll see any for the 6 ARC.

Midway USA has RCBS small base die sets available for 6mm ARC.

Friggin RCBS. Skip the small base dies unless your barrel has a really tight chamber. Otherwise you're just overworking brass and throwing away some accuracy.

 

[Constructor]

Friggin RCBS. Skip the small base dies unless your barrel has a really tight chamber. Otherwise you're just overworking brass and throwing away some accuracy.

Hornady dies are small base too they just don't say it.

RCBS FL dies size the brass .002" under minimum diameter chamber size. RCBS SB size brass .004" under minimum diameter chamber size. ALL Hornady dies size brass .004 under minimum diameter chamber size. Forster FL size brass .002 under minimum chamber size.

 

[Ledzep]

My resized cases out of a Hornady die set come out .0025-.0030 under SAAMI min spec.

ETA: checked some 6.5 Creedmoor cases. SAAMI chamber, Hornady FL die, diameters are .0025-.0032" under SAAMI min chamber. For sure a few tenths worth of spring back on the case. I'd guess .003-.0035 under SAAMI min if a guy was to cerosafe the die.

 

[Constructor]

My resized cases out of a Hornady die set come out .0025-.0030 under SAAMI min spec.

springback.
About 10 years ago I measured brass coming out of specific dies because of some issues people were having. Then I called every manufacturer of dies and talked to the engineers and asked them what the design diameter was and the post above is what they told me. Redding would not answer the question. On top of that Hornady has been making all of the custom dies(batches of 50 at a time) I have made for the wildcats for over 10 years.

 

[skyrep]

I measured 33.8 and someone else had 34.5 on ar15.com

I measured 34.4 with once fired Hornady 6mm ARC Brass.
my measured velocity with Hornady 105 bthp Black was:
Avg: 5 shots 2733 fps - SD: 13.3
avg: 10 shots 2739 fps - SD: 17.9
All from 22" 1-7.5 twist Bolt Uper AR (Uintah Precision) and an Aero Precision Lower.

 

[tomcatfan]

This guy is getting 2+ moa with his CMMG. Many people are saying it’s the ammo, considering Hornady is the only game in town, really?

I get that hand loading can improve loads sometimes, but I’ve never had a rifle shoot horrible with reputable match grade ammo and magically shoot amazing with my reloads. Thats just me though.

 

[ormandj]

This guy is getting 2+ moa with his CMMG. Many people are saying it’s the ammo, considering Hornady is the only game in town, really?

I get that hand loading can improve loads sometimes, but I’ve never had a rifle shoot horrible with reputable match grade ammo and magically shoot amazing with my reloads. Thats just me though.

It's a CMMG barrel. They're a complete crapshoot of a barrel when it comes to accuracy. I've got one in a Colt (5.56) that shoots very well, but every other CMMG I've seen has been a 2+ MOA barrel even with match ammo. I got this one in trade, and it's my first/last that I'll personally own. You can sometimes find a load that'll work, but CMMG is not the direction to go if you want accuracy, regardless of cartridge.

 

[tomcatfan]

2+ moa for this cartridge is unacceptable. The round was designed for long range, and IMO 600 yds is not long range. I have more than 1 small frame AR that is more than capable hitting targets at 700 yds. At 2+ moa, this would perform worse than my 223 wylde rifles even when accounting for better BC bullets.

 

[Yondering]

Hornady dies are small base too they just don't say it.

RCBS FL dies size the brass .002" under minimum diameter chamber size. RCBS SB size brass .004" under minimum diameter chamber size. ALL Hornady dies size brass .004 under minimum diameter chamber size. Forster FL size brass .002 under minimum chamber size.

You must be talking about sizing diameter at the shoulder? That's a bit different than at the base, and nothing except small base dies that I've ever measured size that small at the base. That's the problem with small base dies when they aren't needed.

 

[jbailey]

2+ moa for this cartridge is unacceptable. The round was designed for long range, and IMO 600 yds is not long range. I have more than 1 small frame AR that is more than capable hitting targets at 700 yds. At 2+ moa, this would perform worse than my 223 wylde rifles even when accounting for better BC bullets.

Yes, I would agree 2moa and its a POS. I will tell you I had a 6.5G and the cartridge is a PRECISION cartridge, showing its 6PPC roots. I had no trouble getting well under 1moa handloads. 6ARC cartridge will shoot if the rifle and shooter can.

 

[Constructor]

You must be talking about sizing diameter at the shoulder? That's a bit different than at the base, and nothing except small base dies that I've ever measured size that small at the base. That's the problem with small base dies when they aren't needed.

The base and the shoulder, they said all diameters including .004" tension at the neck.

 

[Blaster7Romeo]

How much factory ammo has made it out there yet ? And any reports about it ?

 

[ormandj]

How much factory ammo has made it out there yet ? And any reports about it ?

Not sure on how much total, but I was able to pick up 20 boxes (108gr ELD-M) fairly easily a month ago. I reload, so haven't been in the market since, I just needed the brass.

 

[Yondering]

The base and the shoulder, they said all diameters including .004" tension at the neck.

That definitely does not match what I'm measuring, on anything except actual small base dies (not Hornady). All my other dies including Hornady don't size the base diameter very much (less than .001") on minimum spec chambers, because it's not needed. However, some size the shoulder diameter more than others, and Hornady dies are one of those, in most cases sizing the shoulder diameter .004"-.006" smaller, compared to Forster and others at only .002"-.004" depending on the cartridge. Interestingly, the Lee dies I'm measuring (including my 6 PPC dies which work for the 6 ARC and other 6mm Grendel-based wildcats) size the shoulder diameter less than Hornady and are closer to Forster dimensions. That Lee 6 PPC FL size die actually works very well for my 243 LBC chambers, matching the body dimensions closely.
When I say shoulder diameter, I'm referring to the body diameter at the shoulder/body junction, just using fewer words.

Based on that, I don't consider Hornady dies to be small base dies like what RCBS makes. IMO true small base dies that size the base diameter down more than needed for most chambers are a detriment to accuracy. I've achieved very good accuracy with Hornady dies though, if care is put into getting low rounout and adjusting dies to match the shoulder datum dimension in the chamber.
YMMV.

 

[awpk03s]

That most recent video with the CMMG is pretty unflattering.