New 6mm Advanced Rifle Cartridge

#3,351
Bantam1 said:
So what is the powder everyone seems to have settled on for the 108 grain loads? I am about ready to start loading for mine. I finally have depleted the factory ammo I bought for barrel break in and learning the platform a little more. I see AR comp for the 90ish grain loads. I am sitting on a full case of 108 ELDM to start load development.

With the factory Hornady 108 I am getting around 2670 for velocity with the 20" Proof barrel. If I can keep it around there I would be happy.
Click to expand...
I think most folks are running LVR, especially if you are looking to match factory velocities. Other similar options would be CFE223 and AA2520. Personally my load with the 108gr is 29.3gr LVR, 450s, 20 thou off, matches up to the factory velocities fairly well, a little faster in warm temps. The 29.1gr to 29.5gr range for LVR has been a sweet spot for me across several bullets in the 95gr to 108gr weights.

Attached is some data Sierra sent me, doesn't include LVR, but has CFE223 which is similar, and for the 100gr and 110gr loads, matches up to Hornady data pretty well. The 107gr data is weirdly low compared to the two other weights bracketing it though.
 

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  • 6MM ARC Gas Gun 52,000 PSI SAAMI Max (2).pdf
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#3,352
Interesting video from Wade at Texas Predator Hunting. He was doing high pressure test in a pressure test rig, running things way above SAAMI, and finally experienced firing pin aperture erosion, flaking, causing FTFire, FTExtract.

Hasn’t had any issues with bolts under normal operation for years.



When I broke bolts in 5.56, I started having FTFeed, because the bolt cracked at the cam pin hole.

I’ve been shooting Grendel since 2009 across a wide variety of barrel and gas system lengths, tons of factory and hand loads, still haven’t broken a bolt or extractor.

I’ve been shooting the 12” CLGS Suppressed as my go-to since 2017, but I take the 17.6” Lilja and 18” LaRue along with it usually as well. Things just run.
 
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#3,353
LRRPF52 said:
Interesting video from Wade at Texas Predator Hunting. He was doing high pressure test in a pressure test rig, running things way above SAAMI, and finally experienced firing pin aperture erosion, flaking, causing FTFire, FTExtract.

Hasn’t had any issues with bolts under normal operation for years.



When I broke bolts in 5.56, I started having FTFeed, because the bolt cracked at the cam pin hole.

I’ve been shooting Grendel since 2009 across a wide variety of barrel and gas system lengths, tons of factory and hand loads, still haven’t broken a bolt or extractor.

I’ve been shooting the 12” CLGS Suppressed as my go-to since 2017, but I take the 17.6” Lilja and 18” LaRue along with it usually as well. Things just run.
Click to expand...

I saw that. I like how Wade is constantly pushing the arc to its maximum to see where it will fail so we don't have too. I want him to push a more exotic bolt like the geissele to its limit to see the differences between a standard vs exotic bolt material. Curious if the geissele platforms can be pushed to 62k or are they just like any other standard AR.
 
#3,354
I’m not an advocate of chasing pressure to try to eek out marginal gains in performance.

I quickly learned to look at load manuals and find powders that generated top-end velocities, but with lower pressures. Let the powder do the work rather than trying to get brave on the bench.

Maybe that’s why I’ve never broken a Grendel bolt, but have velocities that are higher than factory ammo as a general rule, but 2500-5000psi less than SAAMI MAP.
 
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#3,355
6 ARC keeps getting it done.

GVyHRgJ.jpg

OpqIJH6.jpg

ApmM7IO.jpg
 
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#3,356
I have LVR and CFE along with other powders. I have been following this thread for a while. I'm going to start load workup soon and just wanted to double check here to see if any other powders were doing better. It's interesting to see the differences in data for Sierra and Hornady.

Thanks for the help.
 
#3,358
Gtscotty said:
Both nice bucks, especially that 10 pt. What bullet(s) did you use?
Click to expand...

Thanks! He's actually an 11, we have a left side kicker that comes off of the main beam in the genetics out there. I hate getting the odd number points but the genetics are improving for a hill country low fence property. The fat 6 was on my hit list this year since he lacks brow tines. I have been using factory loaded Hornady 108 ELD-M's.
 
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#3,359
To tack on, it's been about a month back, but I tagged a buck and a doe with my 12.5" 6 ARC this year, about 30 minutes apart, using one of my hunting loads developed for my 18" ARC (103gr ELDx, 29.3gr LVR, 450s, 2.24"). Performance was quite good, first shot was a neck shot on the buck that dropped him and then a follow up to the heart from the bottom of the chest angled up the neck. The doe came in on the same trail about 30 minutes later and a shot at 60yds fragged her heart. The neck shot on the buck and the quartering shot on the doe exited.

PXL_20241123_144809017.jpg

PXL_20241123_152255923~2.jpg

PXL_20241123_144552228.jpg


I love the shorty ARC for close in hunting, It's so handy with a can. I put it together about a week before taking those deer and didn't have time to do specific load development for it, so that's coming up after the holidays.
 
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#3,360
Bantam1 said:
I have LVR and CFE along with other powders. I have been following this thread for a while. I'm going to start load workup soon and just wanted to double check here to see if any other powders were doing better. It's interesting to see the differences in data for Sierra and Hornady.

Thanks for the help.
Click to expand...
There is some variance between Hodgdon, Hornady and Sierra, none of them are highest or lowest across the board. Seating depth and bullet design are going to play a big part, the load difference within Sierra data between the 100gr TGK and SBT is a grain, probably due to bearing surface differences. Just like any other cartridge, you've gotta do the load work and with ARs, gotta make sure they are tuned well before putting anything in stone.

CFE223/bullet weight95gr100gr103-105gr107gr108-110gr
Hodgdon30.428.628.928.828.2
Hornady29.429.428.629.1
Sierra29.528.2-29.227.429.2


As a reference for LVR, here is what some of my load workups looked like in my 18" X-Caliber.

PXL-20220720-012439405.jpg


PXL-20230319-191932362.jpg


image.jpg


image.jpg


image.jpg


image.jpg


image.jpg


image.jpg


PXL-20220905-043208306.jpg


Factory loads.

PXL-20220905-043454278.jpg
 
Last edited:
#3,361
Gtscotty said:
To tack on, it's been about a month back, but I tagged a buck and a doe with my 12.5" 6 ARC this year, about 30 minutes apart, using one of my hunting loads developed for my 18" ARC (103gr ELDx, 29.3gr LVR, 450s, 2.24"). Performance was quite good, first shot was a neck shot on the buck that dropped him and then a follow up to the heart from the bottom of the chest angled up the neck. The doe came in on the same trail about 30 minutes later and a shot at 60yds fragged her heart. The neck shot on the buck and the quartering shot on the doe exited.

View attachment 8576462
View attachment 8576460
View attachment 8576461

I love the shorty ARC for close in hunting, It's so handy with a can. I put it together about a week before taking those deer and didn't have time to do specific load development for it, so that's coming up after the holidays.
Click to expand...

I am finding the shorty 6 ARC to be perfect for the field as well. After changing things up annually for the past few seasons I think I have my deer rifle for the next few years.
 
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#3,362
Haven’t had this anywhere but the range, but have it dialed in with 105 BTHP handloads and gassed right with the can.

Looking forward to bloodying it later this year.

Faxon Gunner 16”, AB Warthog 308 can. Timney trigger and Athlon 2-12 scope. The rest are
parts from other abandoned projects.

Balances nicely being held or on the tripod.

IMG_8177.jpeg
 
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#3,363
Odinworks barrel shit the bed. I’ve had nothing but problems with it since purchasing it. Anyone use Shaw barrels? I’d like to replace it with one of theirs if they’re good. Trying to stay away from BA and ranier.
 
#3,364
I got a Satern barrel on my Grendel Hunter upper and it’s an excellent barrel. Worth a look as they sell only barrels too.

6MM ARC Barrels | Grendel Hunter | The Modern Sporting Rifle

6MM ARC Barrels 16" Barrels Shop Now 18" Barrels Shop Now 20" Barrels Shop Now 22" Barrels Shop Now 16" Barrels Shop Now 18" Barrels Shop Now 20" Barrels Shop Now 22" Barrels Shop Now
www.grendelhunter.com www.grendelhunter.com
 
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#3,368
Late season antlerless whitetail Nebraska hunt was a success. Tagged out and the 6ARC performed well. Very cold temps the first two mornings, -9F, so the deer were bedded down in the cedars and holding very tight. Specifics are below but both rounds were recovered just shy of hide on the other side of the animal. No bone was struck that we could see. Very light recoiling platform and a lot of fun. We dispatched a few coyotes as well (way too many out there this year) and deer numbers seem to be down compared to previous years.

Doe 1 shot at 117 yards broadside, vitals. Round 1 recovered below. Factory Hornady Precision Hunter 103 ELD-X met target at 2,357 fps and 1,270 ft lbs of energy. Recovered round weighed in at 73.1 gn with core/jacket separation. Walked 10 yards and expired.

Doe 2 shot at 187 yards broadside, vitals. Round 2 recovered below. Factory Hornady Precision Hunter 103 ELD-X met target at 2,236 fps and 1,143 ft lbs of energy. Recovered round was intact, nicely mushroomed, and weighed in at 75 gn. Walked about 20 yards and expired.

IMG_20250112_160619.jpg

PXL_20250110_170159839.MP~2.jpg


Round 1 recovered
PXL_20250113_175722448.MP.jpg


Round 2 recovered
PXL_20250113_175523793.MP.jpg
 
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#3,369
BravoSector1 said:
Late season antlerless whitetail Nebraska hunt was a success. Tagged out and the 6ARC performed well. Very cold temps the first two mornings, -9F, so the deer were bedded down in the cedars and holding very tight. Specifics are below but both rounds were recovered just shy of hide on the other side of the animal. No bone was struck that we could see. Very light recoiling platform and a lot of fun. We dispatched a few coyotes as well (way too many out there this year) and deer numbers seem to be down compared to previous years.

Doe 1 shot at 117 yards broadside, vitals. Round 1 recovered below. Factory Hornady Precision Hunter 103 ELD-X met target at 2,357 fps and 1,270 ft lbs of energy. Recovered round weighed in at 73.1 gn with core/jacket separation. Walked 10 yards and expired.

Doe 2 shot at 187 yards broadside, vitals. Round 2 recovered below. Factory Hornady Precision Hunter 103 ELD-X met target at 2,236 fps and 1,143 ft lbs of energy. Recovered round was intact, nicely mushroomed, and weighed in at 75 gn. Walked about 20 yards and expired.

View attachment 8591064
View attachment 8591065

Round 1 recovered
View attachment 8591068

Round 2 recovered
View attachment 8591070
Click to expand...

Great feedback with the recovered rounds and retained weight.
 
#3,373
Gtscotty said:
Just saw that PSA is introing a 6 ARC Sabre with increased bolt and barrel extension lug size and a lower sized to fit the new Magpul ICAR 6 ARC mags. Looks like their starting off with a 14.5" P/W upper with more to come. Hopefully this means their AAC 6 ARC ammo is getting close to hitting the market.

Click to expand...

I saw that too. Very interesting about the increased bolt and barrel extension. Curious to see what is different about the extension from what Craddock and others have done. Very interested in whether their upper will mate to a regular lower. Bodes well for new ammo and longevity of the cartridge.
 
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#3,376
Rob01 said:
I got a Satern barrel on my Grendel Hunter upper and it’s an excellent barrel. Worth a look as they sell only barrels too.

6MM ARC Barrels | Grendel Hunter | The Modern Sporting Rifle

6MM ARC Barrels 16" Barrels Shop Now 18" Barrels Shop Now 20" Barrels Shop Now 22" Barrels Shop Now 16" Barrels Shop Now 18" Barrels Shop Now 20" Barrels Shop Now 22" Barrels Shop Now
www.grendelhunter.com www.grendelhunter.com
Click to expand...
What type of accuracy are you seeing with factory ammo or Handloads? I’ve been looking at them since the craddock RTR went out of stock
 
#3,377
Jdowns0415 said:
What type of accuracy are you seeing with factory ammo or Handloads? I’ve been looking at them since the craddock RTR went out of stock
Click to expand...

During my break in this was 5 shots at 550 yards. The first went off at three o’clock and I adjusted for wind and hit these 4. I have shot it to 1000 and I am very happy with the accuracy with factory 108 ELDs. Haven’t loaded anything for it yet.

IMG_4419.jpeg
 
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#3,379
Giessele matched set
Giessele mk18 arca rail
All Giessele small parts, tubes, buffer, spring, CH
Giessele SD-E trigger
Proof 22in +1 RLGS 6 arc Barrel
Superlative arms AGB .875 pinned
Jp enhanced Grendel Bolt
Bootleg adjustable Carrier
Magpul PRS Lite Stock
KGM R30K suppressor
Leupold MK4HD 6-24 PR3
giessele super ar15 mount
Send it level
MDT MLOK weights
 
#3,380
DeathBeforeDismount said:
Giessele matched set
Giessele mk18 arca rail
All Giessele small parts, tubes, buffer, spring, CH
Giessele SD-E trigger
Proof 22in +1 RLGS 6 arc Barrel
Superlative arms AGB .875 pinned
Jp enhanced Grendel Bolt
Bootleg adjustable Carrier
Magpul PRS Lite Stock
KGM R30K suppressor
Leupold MK4HD 6-24 PR3
giessele super ar15 mount
Send it level
MDT MLOK weights
Click to expand...
Nice, building something pretty similar, but with an 20inch Proof carbon barrel. VLTOR and haven’t decided on a lower or if I’ll just canabalize one for awhile. I hope the Aero adjustable gas fits under the hand guard. You building it yourself? Trigger? Looking at a GEISSELE Super Dynamic Enhanced Trigger.

Why that suppressor? Still looking at suppressor versus a comp.

Pics?
 
#3,382
FromMyColdDeadHand said:
Why that suppressor? Still looking at suppressor versus a comp.
Click to expand...

I am actually in the process of getting a suppressor for mine. Just seems like a good combo. The brake works great on it now but would be nice to quiet it down. My suppressor is still in jail but I ended up getting a B&T SRBS 7.62. I was going back and forth between it and the HuxWrx Ventum 7.62 but the B&T had a free tax stamp so it won. lol
 
#3,383
FromMyColdDeadHand said:
Nice, building something pretty similar, but with an 20inch Proof carbon barrel. VLTOR and haven’t decided on a lower or if I’ll just canabalize one for awhile. I hope the Aero adjustable gas fits under the hand guard. You building it yourself? Trigger? Looking at a GEISSELE Super Dynamic Enhanced Trigger.

Why that suppressor? Still looking at suppressor versus a comp.

Pics?
Click to expand...
Yea i will build it myself.

Its a short, super light, low back pressure can that is very economical and performs very well. Less weight hanging off the end of the barrel should mitigate stringing with the AR. The real benefit of a suppressor with the AR is being able to get the recoil down and still be reliable.

All the G triggers are great, but the SD-E is my favorite.
 
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#3,385
Either will work but depends on the bullet weight you plan to use a majority of the time. I think 7.5 is used a lot as some want to use 108 but also lighter bullets as well so if you get a 7.5 you will be fine with the cartridge. Even 7 with the velocities you will get from the cartridge you won’t be blowing up lighter bullets.
 
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#3,387
DeathBeforeDismount said:
Ive seen a bunch of 108s blow up out of a fast twist creed but the arc should get no where near those rpms.
Click to expand...
Well if they were Hornady eld-m they’ve been blowing up in 6.5 PRC a long time. Maybe other calibers. Shit design and the fact that they deny it…fuck em. I don’t hate the company as a whole but fucking own your shit.
 
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#3,389
Seekins 18” Proof CF 1:7.5 (barrel was new)
Garmin Xero

Hornady Black 105gr BTHP
2942, 2527, 2532, 2521, 2546
2530, 2535, 2552, 2533, 2547
SD 16 ES 59 1.2”
Hornady 106gr TAP
2596, 2587, 2583, 2592, 2599
2604, 2584, 2592, 2597, 2605

Hornady 108 ELDM Factory
2483, 2500, 2493, 2491, 2526
2495, 2477, 2513, 2485 SD 12.5 ES 39.7

Hornady 106gr TAP
2596, 2587, 2583, 2592, 2599
2604, 2584, 2592, 2597, 2605
SD 7.5 ES 22.6 2”

Berger 108 Elite Hunter
29.3 LVR
2640ish for comparison
 
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#3,392
I don’t recall exact numbers, but factory 108’s were giving me 2750ish average first time out with my 22” barrel. 2600+ in two different 18” barrels.
Stacked it deep 2-3 years ago and wonder if maybe Hornady loaded it a bit warmer than current production. Can’t touch this velocity with newer factory 103’s that I have.
 
#3,394
Is your 22” a bolt or AR? Mine is an AR but even in my 26” bolt gun it’s only at 2725fps for the 2580 lot. I never shot the 2650 lot through the bolt gun.
 
#3,395
It’s a factory Seekins DMR that I picked up on a whim for $1386 w/free shipping. Battlehawk was clearing out the battle-worn finish models so I bit and ordered one.

Bought cases of 108’s a few years back for cheap, and it’s easily faster than any of the 103 or 105 stuff I have. My gut says they were loading it hotter back then. No pressure signs on brass, so I won’t complain.
 
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#3,396
Shoreglide said:
It’s a factory Seekins DMR that I picked up on a whim for $1386 w/free shipping. Battlehawk was clearing out the battle-worn finish models so I bit and ordered one.

Bought cases of 108’s a few years back for cheap, and it’s easily faster than any of the 103 or 105 stuff I have. My gut says they were loading it hotter back then. No pressure signs on brass, so I won’t complain.
Click to expand...


What’s the lot number?
 
#3,399
Shoreglide said:
3231484
Click to expand...

That’s only a 2023 lot so not that long ago. Both my lots that shot the 2580 area are also 2023 lots also. The 2024 lot I have is at 2650. Would be interesting to see that ammo shot in a different rifle and see what it did. Consider yourself lucky though for getting that velocity though.
 
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