New 6mm Advanced Rifle Cartridge

Not linear. Usually from a 70 degree baseline going cold (-20 degrees) will be about half the fps/deg value that going up to hot (140 degrees) will with *most* rifle spherical powders. That being said, I think if you keep it under 100 degrees it would smooth that out a lot and make it much more linear. Somewhere around 1.5-2 fps per degree sounds about right for LVR, if you take a look at Lennyo's numbers.
Thank you sir. I've got all kinds of mixed info when asking about it. Everything from info similar to yours...all the way to 'powder sensitivity is over exaggerated'. LVR is not a bad powder by any means in my opinion, but I choose more stable for where it may matter most. I can't always shoot the difference in plus or minus 40-60 fps (for example only), but I want to reduce variables to accurately gauge my personal performance.

I still have 12lbs or so of LVR, it's great. I'm getting ready to load some for this weekend doing positional practice for an upcoming match.
 
108eldm box ammo
26” bartlein m24 barrel turned to fit
2775fps
Palmetto state monolith .556 can.
Superlative arms piston system
Trigger tech diamond
Seekins upper and lower

Gun built by Andy at River City Rifles
This thing is awesome.
 

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Thank you sir. I've got all kinds of mixed info when asking about it. Everything from info similar to yours...all the way to 'powder sensitivity is over exaggerated'. LVR is not a bad powder by any means in my opinion, but I choose more stable for where it may matter most. I can't always shoot the difference in plus or minus 40-60 fps (for example only), but I want to reduce variables to accurately gauge my personal performance.

I still have 12lbs or so of LVR, it's great. I'm getting ready to load some for this weekend doing positional practice for an upcoming match.
LVR sucks if you go from 70-100, in my experience. Somewhere in the high 70s to low 80s pressure shoots through the roof if you develop a load that works well below that, at least that's what happened when I tested the powder. That's ~half the year in Texas, from morning to noon, so it's a pain. If you develop a load above, and then it cools, velocity will fall off a cliff.

As long as your climate stays out of crossing that 'danger zone' (which is likely 6ARC specific, different powders behave differently in different cartridges, which is why you'll see a lot of feedback saying different things), LVR is great for speed. RL26 in 6.5CM is exactly the same, I cannot use it in TX since I shoot from dawn to dusk quite often.
 
It's more or less the same for me. I'm in SW Louisiana so weather is pretty much yours a few hours later. I know where my Max is at 95*, as far as what I can get at lower temps...I could care less. I use it for practice fodder, same with my Hornady BTHPs. All the H4895, VV and bergers get saved for matches / classes until availability improves.
 
108eldm box ammo
26” bartlein m24 barrel turned to fit
2775fps
Palmetto state monolith .556 can.
Superlative arms piston system
Trigger tech diamond
Seekins upper and lower

Gun built by Andy at River City Rifles
This thing is awesome.
This is a great looking rifle! I am wanting to build something similar with Seekins. How do you like the feel of the Seekins upper / lower? Anything you would do different now that you have it in hand?

Couple more questions for you:
What grip?
What Arca rail?
What XLR buttpad?
 
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This is a great looking rifle! I am wanting to build something similar with Seekins. How do you like the feel of the Seekins upper / lower? Anything you would do different now that you have it in hand?

Couple more questions for you:
What grip?
What Arca rail?
What XLR buttpad?
Thanks! No I wouldn’t change anything really I really like the seekins upper and lower. Fit is perfect and tight.

Ergo vertical grip
Sawtooth rifles arca rail
I think it’s an xlr tactical butt stock
 
Thanks! No I wouldn’t change anything really I really like the seekins upper and lower. Fit is perfect and tight.

Ergo vertical grip
Sawtooth rifles arca rail
I think it’s an xlr tactical butt stock
Excellent, thanks... that is just about the same build I am looking for, but maybe with a JP Bolt carrier and silent capture spring.
 
FWIW, I just put 5x8lb jugs of LVR for sale on the classifieds section for folks in TX. I’m too lazy to maintain winter/summer loads, and I travel a bunch to shoot, so it doesn’t do me any good. Best speed in this cartridge, but don’t expect a -20F to 110F stable single load.

On a second note, @thelaststraw, you’ve found N140 stable in 6ARC?
 
I don't know yet about N140s performance in the heat. I've only been using it for a few weeks now and It hasn't been in the 70s even in SW Louisiana when I get to the range. It is a dream to work with though. Very similar case fill to H4895 and getting good velocity too. Super clean with a suppressor....cleanest powder I've loaded in anything to date. I'm having high ES just today actually but I think it may be a neck tension/brass prep issue. But it was also the first time I ran more than 5 across the Magnetospeed (20rds).
 
I don't know yet about N140s performance in the heat. I've only been using it for a few weeks now and It hasn't been in the 70s even in SW Louisiana when I get to the range. It is a dream to work with though. Very similar case fill to H4895 and getting good velocity too. Super clean with a suppressor....cleanest powder I've loaded in anything to date. I'm having high ES just today actually but I think it may be a neck tension/brass prep issue. But it was also the first time I ran more than 5 across the Magnetospeed (29 rds).
I love VV powders, in general, for many of the reasons you mentioned. They just cost a good bit and can be a bit harder to find. I’ve got a local source with a bunch so I’ll pick up a pound or two to try out. It sounds like VV is advertising newer lots as temperature stable; the older stuff I used was not, they must have changed the formulation. Thanks for the tip!
 
From what I've heard the 5xx are faster and a little touchy in temp compared to the 1xx powders. I don't know personally, just what I've read lurking around F class types. They are pretty particular about the smallest details.
 
I just found an 18” Odin barrel for a price I couldn’t pass up, so I guess I am getting into the 6mm ARC game. From reading through this thread I understand this barrel is not super well regarded due to the rifle+2 gas having short dwell time, but I’m not sure how worried I should be about it. If I am only running factory ELD M and X loads with a carbine SRS buffer setup and a Seekins Select gas block, do y’all think I should be ok? It will probably be run suppressed 90% of the time, but I’d like the option to use it without the can too. It seemed like most of the problems came with rifle buffers, poor-fitting gas blocks, or lighter varmint loads, so I am hoping I won’t have to switch buffer systems to get it running.
 
I have no experience with that specific barrel. I do run a suppressor nearly always and can say for sure that 6 ARC is a very gassy cartridge. You should have no problems with the can on and I doubt you will have any unsuppressed.

Definitely run a good adjustable gas block though. There are some here with first hand experience with that barrel or much, much more experience with this platform that may have more accurate beta than me though. Just my findings...btw, I don't regret ever going +2 gas on my 24" with a can.
 
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My first barrel was an Odin, I went through some teething problems with it. I run a rifle length RE and stock, Odin never did any R&D with rifle length buffer setup. I ended up using a 10% ruduced power spring and replaced three of the steel weights in the buffer with aluminum to lighten it. Results were one of the softest shooting rifles I own, recoils like a .22. I can watch the holes getting punched in the target through the scope. My gas block is almost closed, sending very little gas to the BCG, rifle runs very clean and is .5 MOA or better with my loads. You will not be disappointed with that barrel. I have been shooting this barrel 2 weeks after this platform was released in June 2020. Get their muzzle brake, it works very well on that barrel.
 
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I have no experience with that specific barrel. I do run a suppressor nearly always and can say for sure that 6 ARC is a very gassy cartridge. You should have no problems with the can on and I doubt you will have any unsuppressed.

Definitely run a good adjustable gas block though. There are some here with first hand experience with that barrel or much, much more experience with this platform that may have more accurate beta than me though. Just my findings...btw, I don't regret ever going +2 gas on my 24" with a can.

I’ve heard it is a dirty round, so will be running a Seekins Select for suppressed adjustment. One advantage of the long gas system here is that I think the lever of the Seekins should stick out just past a 15” handguard making tool-less gas adjustment possible.

My first barrel was an Odin, I went through some teething problems with it. I run a rifle length RE and stock, Odin never did any R&D with rifle length buffer setup. I ended up using a 10% ruduced power spring and replaced three of the steel weights in the buffer with aluminum to lighten it. Results were one of the softest shooting rifles I own, recoils like a .22. I can watch the holes getting punched in the target through the scope. My gas block is almost closed, sending very little gas to the BCG, rifle runs very clean and is .5 MOA or better with my loads. You will not be disappointed with that barrel. I have been shooting this barrel 2 weeks after this platform was released in June 2020. Get their muzzle brake, it works very well on that barrel.

Glad to see you’re getting good accuracy results. Also good that you were able to get it running smoothly, but I’m really hoping not to have to mess with springs or buffers with a carbine setup.

For now this one is gonna be wearing a Dead Air Xeno radial brake for ease of use with my Nomad LT, but the brake doesn’t do all that much for recoil management - I think it’s similar to a MAMS / AFAB in that it’s an attempt to balance recoil, blast, and flash. I am hoping Dead Air or their industry partners will release a more serious brake for Xeno soon.
 
My first barrel was an Odin, I went through some teething problems with it. I run a rifle length RE and stock, Odin never did any R&D with rifle length buffer setup. I ended up using a 10% ruduced power spring and replaced three of the steel weights in the buffer with aluminum to lighten it. Results were one of the softest shooting rifles I own, recoils like a .22. I can watch the holes getting punched in the target through the scope. My gas block is almost closed, sending very little gas to the BCG, rifle runs very clean and is .5 MOA or better with my loads. You will not be disappointed with that barrel. I have been shooting this barrel 2 weeks after this platform was released in June 2020. Get their muzzle brake, it works very well on that barrel.
That seems like quite the challenge with great results. Tuning everything all together. Having not shot ARs much before this I didn't think recoil tuning mgmt was that much of a thing. Then I started landing double and triple hits at 600 and 750 with shots at 1k and yeah it definately matters. I have no can so using a good brake helped.

I just saw a NEW Adjustable Gas block that has a small cage between the handguard and barrel for really quick adjustment with no tool. they have them in snubby and 4" extensions. It looked pretty legit cost $200 - saw it on the WLS podcast recently. If you were contstantly adjusting the GB I could see it,.

EDIT: Rifle Speed gas block: https://www.riflespeed.com/RIFLESPEED-Gas-Controls_p_12.html

I'm working on my third restoking pile of 6ARC ammo this week.
 
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I have that exact barrel, 18” Odin w/ +2 gas.

I shoot it on a rifle length stock with the standard spring and buffer that came with the rifle length buffer tube.

I thermal fitted it to a BCM upper. I use a suppressor almost exclusively and the Odin tunable gas block is almost all the way closed.

It is super soft shooting and well under moa with factory ammunition with the exception of the TAP loads, which are 1.5-2moa.

I bet you’ll be happy with your barrel.
 
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Looking for load data on Hodgdon H 380, with 105 or 108S has anyone here explored the powder? Picked up a few pounds locally to toy with. Looks like a good candidate falling between Lever and MR2000. Cant find anything on the web.

My Odin 18" plus 2, is hovering around .8 repeatable for factory 108 ELDMs, and best hand load so far is the 105 hybrids jumped 70, Starline 6.5 brass, maxed 28.7 of Lever is in the repeatable .7's. Installed a reduced recoil spring, and now have no running issues non suppressed. Shoots like a pussy cat. Got in on the cyber-week ARC sale on a Nucleus, and have now started a bolt build in the caliber to really have some fun. American Rifle Company shooting the American Rifle Cartridge, Donald would be proud
 
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Wow, that is awesome. I was looking at the ARC offerings earlier this year, but there was a wait time (understandably) for the different cartridge I wanted 300PRC...

I tested a few rounds yesterday.
I had a couple feeding issues with some of them, and the 108EH didn't seem to be as accurate, but I was shooting at 6"steel gong @200 so I'll save the accuracy thing for later on.
I ran all these over LL @~2600fps - Match prepped brass and wolf sm mag primers
105 Nosler CCs
108 Berg EHs
105 Berg VLDs
confirmed scope dope. I think my feeding issues were on the berg 108s that I loaded long, I may try seating them a little deeper.
There were a lot of people at the range, it was great weather, lot of reloaders on the rifle range. great day.
I tested some pistols too..
 

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You did tell me to tell you that....

But it does look like a good way to sling 100gr bullets at 30-30Win speeds

Yes, I suppose I did. I had to look up what 30-30 speeds were for a 100-ish gr bullet, Hodgdon gives a max velocity of 2,684 for some 110gr. I guess that is vaguely in the ballpark but Hornady's bolt gun specific 6mm ARC data tops out at 2,850 fps for 105 gr -108 gr out of a 24", so maybe 2,800 or so out of the stock mini's 22" barrel and 2,700 ish out of my future mini bobbed to 18". I've killed deer and antelope with similar and lesser ballistics, and I bet it would carry like a mini version of my Creedmoor Kimber Montana.
 
I use a bolt action 6.5grendel for whitetail. I actually think it's the perfect east coast deer rifle. 100gr Nosler BT's at 2730fps. This year I'm probably going to use a 20" 6.5 Creedmoor shooting 120gr Speer Gold Dots at 2800. I kinda wanted to chamber that rifle in 6.5 Grendel but it just wasn't worth fucking with all the mag feeding, figured a short barreled 6.5CM was close enough. I also thought 20" would be a perfect barrel length. It almost looks stupid and unbalanced though.
View attachment 7755606

There's just a ton better hunting bullets for 6.5mm. I have a 6 Creed barrel for this rifle but the 6mm hunting bullet selection sucks and it's a little more explosive than I'd like with 90gr TGKs at 3050. That barrel unfortunately just doesn't like the heavier 6mm bullets. No idea why.

My Grendel is an AR, but have/had hunting bolt guns in 6.5 Creed with 18"-22" barrels that I've killed a few elk, muleys and antelope with. In my opinion, the Creed is in a different class from the Grendel due to its ability to sling heavier, better, bullets much faster, even in shorter barrels. Most of the best 6.5 hunting bullets are in the 130gr to 143gr range where the Grendel is sucking wind (starting at literal 30-30 velocities). Not to say there aren't some good options in the 120gr range, but certainly fewer than in the more popular weights.

I used the120gr gold on an antelope out of my Grendel a few years ago, and was not overly impressed with the wound cavity or the several hundred yards the antelope went with a pencil hole through both lungs. That bullet started at ~2,430 fps and struck at 175yds, I'm sure a faster starting velocity would have resulted in better expansion/performance, or alternatively using one of the other relatively few bullets actually designed for Grendel velocities, like the 123gr SST, that I've subsequently switched to.

What interests me about a light bolt gun in 6mm ARC over another Grendel is that I should be able to get any of the decent 6mm hunting bullets like the 90gr AB, 95gr BT, 90gr TGK, 90gr ELDx, 103gr ELDx, etc, up to the 2,700 - 2,900 fps MV range that I prefer for reliable downrange expansion and quick killing. I can't get that out of my Grendel with even 120gr bullets (maybe I should try to find some 100gr BTs), although obviously my Creeds are more than capable. Obviously bullets matter, but so does impact velocity. I've killed a few deer with the 95gr BT, and was happy with the performance at ~3,000 fps, I bet it would do just fine a hundred or two hundred fps slower.
 
Anyone know where to find a 6arc bolt for an AR?

 
Thanks!
 
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Okay I have a slightly different question. Where can I find a LH bolt? I could be up the proverbial "creek" as I assumed my Stag LH bolt from my 6.8 spc would work.

Maxim is good to go.
 
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CCI #41’s in stock. I am set but I know some of y’all use them. Pricey...

 
Every once in a while, the local sportsman’s gets a few bricks in for $41/1,000.

There’s no way I’d pay Brownells prices plus shipping and hazmat.

In fact, this gouge-fest puts them on the same list as MidwayUSA, namely the “do not buy” list.

I’m so done with these knuckleheads.
 
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Took my handloads to 1000 yesterday and was pretty disappointed.

I developed the load of 29.0 lever evolution under 105 hybrid back in May. Gave me 2740fps with single digit SDs in 80 degree weather.

That same load in mid 30s temperature yesterday dropped to 2630 with SDs in the 30fps range. ES was over 100.

I had misses high and low on a full size ipsc at 1000. Never missed a shot to wind(consistent that day).

Factory Hornady held a decent group. Around MOA at 1000. Unfortunately I brought very little of it.

I knew lever evolution is temperature sensitive but didn’t expect it to be this bad. I shot a few one day matches with this load and rifle last summer and did well. Was planning to take this to a 2 day match but not if performing like yesterday.

Quoting myself with update.

Went back out today, this time with factory Hornady 108s . Very consistent hits at a IPSC at 1000. 7 for 10 on a 10” plate at 960. Misses were not far off although not all to wind. Conditions were pretty favorable today.

Velocity in summer with this ammo was 2740 with SD around 12. Today was 2690 with SD around 15. Not quite as good but still serviceable.
 
About a year in the making, finally got out to shoot my 6 ARC build this past Monday. Only ran 40 rds of factory Hornady 108 ELDM through it, but it performed flawlessly and looks to be a keeper. Groups are about 25 rds in and after being cleaned.

Upper
Aero Precision M4E1 upper squared by DTech
Shilen Match Grade 20", medium contour, rifle length gas, fluted, threaded. Built and headspaced to my Aero Precision bolt by DTech
SLR Ion Lite 13.7" Handguard
Aero Precision Gas block, low profile, .875", black nitride
BCM Ambi 3x3 Large Charge handle
Aero Precision Bolt Carrier Group
Seekins MXM 34mm scope mount
Burris XTRII 4-20x 50mm, 34mm tube
Lower
Aero Precision M4E1 Lower
Triggertech AR Adjustable
Aero Precision Enhance Carbine Buffer Tube with H2 Buffer and JP Spring
Ergo Tactical Grip
Luth-AR MBA-3 Carbine Stock

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First round clean bore flier
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My go to gun is a 16in proof barrel 6mm arc in a SR-15. Took down my first deer with a 108 eld factory round this past week. Solid sized doe, it was running, shot it in the stomach and the round fragmented and still damaged the lungs and heart. Didn't walk 20 feet before it died. I get about 1/2 - 1/4 MOA on the range with factory ammo if I'm having a good day shooting.
 
Finished the other batch of blank brass converted. There were about 20 rounds that had dents, deformations. Its' a lot of work. I would just normally wait for 6.5 Gr brass but I had it from last year.
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loaded 20 to test with 105 VLDs and 100 Horn BTSP.
I'm about to put the ATN back on and maybe do some yote hunting this weekend.
Good groups to all you guys!