Geissele 6 ARC in service with SOCCOM, some hands on comments.

ut755ln said:

As many of you know Geissele won a SOCOM contract and has been making deliveries of a small framed AR chambered in 6mm ARC. These comments are from my son who works with Naval Land Warfare.

The teams really like the rifle. Geissele won a pretty grueling competition and apparently they were very innovative. Some of the specific things that Geissele did include, a redesigned feed ramp for increased reliability with the 6mm. Steel inserts in the upper receiver to again help with reliability and durability with the higher pressure. A completely redesigned BCG made with a new steel that increased service life by 300%. A CHF chrome lined barrel that is getting close to the same accuracy as a stainless barrel with almost 200% more life between replacements. A ground up redesign of the magazines which apparently is a big deal. They are straight mags, not like 6.5 mags with the curve. It allows the use of current plate carriers without having to reconfigure them. The DMR guys like that they 6 ARC effectively has the same range as the .308 and similar wind fighting capability but they are able to carry 40% more ammo then a .308 loadout and still are lugging around less weight. For those of you that care, they are pairing them with some kind of 3x20 Schmidt and Bender short scope. The current accepted loadouts include a 14.5" variant and an 18" variant. They are currently evaluating a 12.5" variant and I think he said a 20".

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Amazing how similar the DOPE is between 6 ARC 108 ELD-M and 178 grain ELD-X 308 out to 700 yards.

It would be interesting to know all the changes in feed geometry due to the new mags and ramps

ut755ln said:

As many of you know Geissele won a SOCOM contract and has been making deliveries of a small framed AR chambered in 6mm ARC. These comments are from my son who works with Naval Land Warfare.

The teams really like the rifle. Geissele won a pretty grueling competition and apparently they were very innovative. Some of the specific things that Geissele did include, a redesigned feed ramp for increased reliability with the 6mm. Steel inserts in the upper receiver to again help with reliability and durability with the higher pressure. A completely redesigned BCG made with a new steel that increased service life by 300%. A CHF chrome lined barrel that is getting close to the same accuracy as a stainless barrel with almost 200% more life between replacements. A ground up redesign of the magazines which apparently is a big deal. They are straight mags, not like 6.5 mags with the curve. It allows the use of current plate carriers without having to reconfigure them. The DMR guys like that they 6 ARC effectively has the same range as the .308 and similar wind fighting capability but they are able to carry 40% more ammo then a .308 loadout and still are lugging around less weight. For those of you that care, they are pairing them with some kind of 3x20 Schmidt and Bender short scope. The current accepted loadouts include a 14.5" variant and an 18" variant. They are currently evaluating a 12.5" variant and I think he said a 20".

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Interesting. I wonder if this portends an eventual shift from 5.56 to 6 ARC as the basic issue round. Granted, not as easy to do as just start giving out 77gr, but...

General RE LEE said:

Amazing how similar the DOPE is between 6 ARC 108 ELD-M and 178 grain ELD-X 308 out to 700 yards.

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About as amazing as mk262 vs m118lr.

In my experience 0-600/700yds......any reseasonable round for longrange shooting is close in trajectory.......extreme outliers excluded.

Your 28" 22creedmoor is NOT similar to your 16" 308 gasgun........haha.

Sounds like Geissele really put in the work, congrats to them and I hope some of that new tech finds its way to the civilian market.

Ern

Would love to see/hear more about the ground up mag design. What capacity for the straight mags? Aren't most of the straight 6.5G mags already on the market of the 15-17rd variety? Probably not a huge deal for a DMR, but if you're going in the front door with a 12.5" maybe you'd want more capacity?

Looks like they did a single layer wall for the front of the magazine, attached to the side wall away from the meplats to allow longer COL.

I’m not seeing where the optic is on the website.

I’m interested in the bolt carrier design

Geissele used forged C-158 for the bolt to increase the strength.

SOLGW is using AerMet for 6mm ARC bolts.

LRRPF52 said:

Geissele used forged C-158 for the bolt to increase the strength.

SOLGW is using AerMet for 6mm ARC bolts.

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Interesting the “better” bolt should be SOLGW. Wonder why G went with C158.

$115 for a 20rd mag, I was expecting it to come in a 3 or 4 pack! I don't operate hard enough to spend $115+ on an AR15 mag.

Very interested in the carrier / feed ramp upgrades though. My limited experience with the ARC has been very favorable with the JP bolt and Proof SS barrel (very consistent hits on 33% IPSC @ 780yds with 10-15mph winds).

Interesting they are running SB 3-20's on the longer rifles. I'm not an SB guy, but something in the form factor of the MK5 2-10 seems much better suited for this cartridge

rlsmith1 said:

$115 for a 20rd mag, I was expecting it to come in a 3 or 4 pack! I don't operate hard enough to spend $115+ on an AR15 mag.

Very interested in the carrier / feed ramp upgrades though. My limited experience with the ARC has been very favorable with the JP bolt and Proof SS barrel (very consistent hits on 33% IPSC @ 780yds with 10-15mph winds).

Interesting they are running SB 3-20's on the longer rifles. I'm not an SB guy, but something in the form factor of the MK5 2-10 seems much better suited for this cartridge

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It’s from G he’s gonna get you somewhere lol.

Kadams1563 said:

It’s from G he’s gonna get you somewhere lol.

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I’m fine overpaying for something, but not the magazine body, spring, feed lip geometry R&D, follower R&D, AND cool guy points

When my buddy was working at Surefire they built a rig to test 5.56 bolts. They had varying results of "milspec" bolts lasting from 12-25k, some longer. They tried several bolts on the market made of 9310 or other materials trying to find the "best" for something they were working on. Not many went more than 30k according to him. He said the failures were mostly lugs and cracks where they normally happen. He didn't mention any bolts breaking at the cam pin hole. Probably hard to duplicate in a test fixture.

He said the G bolt lasted well over 125k cycles in their rig and they stopped testing. The only other bolt that lasted that long was the HK 416 which is also forged. The "158+" they are using is proprietary to G for now. I think the forging has more to do with it. I'm no simp for Geissele but I picked up one of the BCG's from them on a sale and so far zero issues. The coating they are using seems to handle wear very well. Maybe if/when my JP fails in my 6 ARC I will get one of the G bolts.

Kadams1563 said:

Interesting the “better” bolt should be SOLGW. Wonder why G went with C158.

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Could be because of cost and limited availability of aerospace alloys of that nature, and the fact that you can make a perfectly-robust Grendel bolt with common alloys, especially with better processes.

Over the past 15 years of me shooting 6.5 Grendel, you’d think I would have broken a bolt by now. I have only broken 5.56 bolts that were run in extreme high volume torture sessions training CQM though. Colt Canada said they scratched their heads when they started hearing about M4’s breaking bolts back in the 2000s, because they’ve been supplying UK and other NATO SOF units Colt Commando carbines for decades and never heard of this problem. They do their bolt manufacturing and inspection processes much differently than Colt USA was doing per US Mil-Std TDP, namely the stupid 100% HPT mandated for every bolt.

Colt Canada engineers said that HPT on M4 bolts is stupid.
Bill Alexander said it’s stupid.
Reed Knight III said it’s stupid.

It’s probably safe to say it’s stupid and if anyone doubts it, look at why units who have a choice rejected the M110 in favor of SR-25s without the HPT done to the bolts, then look at who was breaking M110 bolts and not SR-25 bolts.

Geissele is approaching the bolt manufacturing processes from forging the blank first from quality C-158, then machining and heat treating it properly to make a robust bolt.

SOLGW is approaching it the same way FN did the SCAR-H, POF did the Revolution, and Ruger did the SFAR using exotic aerospace alloys with their inherent material strengths.

I know Alexander Arms used to use a select-fire 10.5” shorty Grendel to test mags and different things, so a quality, long-lasting bolt has always been doable. More than one way to skin this cat that work.

Has anyone here killed a JP 6ARC/6.5Gren bolt and if so at what round count?

tex68w said:

Has anyone here killed a JP 6ARC/6.5Gren bolt and if so at what round count?

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I’ve heard of someone breaking an extractor on their JP Grendel bolt, but not the bolt itself. They generally seem to hold up very well.

The current available bolts and extractors to beat are the Rexus or older Monster logo bolts.

I have yet to hear of anyone breaking even an extractor on one of those. I’m not saying it hasn’t happened, just that I have not heard or seen of it on the troubleshooting/help threads on the Grendel Forum over the years since the introduction of those bolts.

I’ve been running the older Monster logo bolts on 12” CLGS suppressed Grendels since 2017 without a single issue. The newer Rexus bolts are even stronger.



I figured 12” CLGS suppressed with high efficiency/high back pressure cans would be the combo to break a bolt or extractor, if anything, but just have not seen anything yet.

I am running Bootleg adjustable carriers in all the really short barrel guns suppressed, which chokes the amount of gas that’s allowed to enter the sleeved internal expansion chamber in the BC. I always check for receiver face squareness as well.



I am at a large range complex multiple times throughout the year, almost always for 2 and 3-day DM courses where I loan out the 12” Grendel if someone has a problem with the AR-15 they brought. That 12” Grendel just runs and runs.




I’m getting to the point now where my 5.56 guns are falling into the Retro category only. My most modern 5.56 guns are a SOPMOD Block II full-length RIS that I almost never shoot, a JP float tube with FSP cut on a 16” fluted Bushmaster barrel build, and a BCM 14.5” MLGS with Troy 13” handguard. I think everything else 5.56 is Retro, as in a 605s, 727 JSOC, 723 JSOC in the works, stuff like that.

I kinda wish my retros were Grendels too, as I would shoot them more. An XM177E2 or GAU-5A/A in Grendel would be sick, especially with a little optic.

Ledzep said:

https://geissele.com/parts-tools/magazines.html

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Wow, they're pretty proud of that new mag design.

LRRPF52 said:

Geissele used forged C-158 for the bolt to increase the strength.

SOLGW is using AerMet for 6mm ARC bolts.

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I wonder who their subk is. If it’s LMT, I’d pass…they’ve proven they don’t know how to heat treat AerMet alloys anymore.

TheOE800 said:

I wonder who their subk is. If it’s LMT, I’d pass…they’ve proven they don’t know how to heat treat AerMet alloys anymore.

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What happened? Did something come apart?

What bullet is being used in this application?

LRRPF52 said:

What happened? Did something come apart?

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Where you been the last four years?

TheOE800 said:

Where you been the last four years?

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I’ve seen some general complaints about LMT QC loosening up, but nothing about critical components failing.

LRRPF52 said:

... I am at a large range complex multiple times throughout the year, almost always for 2 and 3-day DM courses where I loan out the 12” Grendel if someone has a problem with the AR-15 they brought. That 12” Grendel just runs and runs.

...

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What magazine is that?

ASC. I shoot ASC 25rd, old CPD, Amend2 polymer 10rd, and whatever I have basically. I de-edge, blend, and polish my barrel extensions and chamfer my ejectors as reliability enhancements. I also use extra power action springs, standard weight 2.9oz carbine buffers, and sealed gas blocks. I like a tight gas system without leaks all over the place.

Geissele mentioned something about changing the geometry of the barrel extension feed ramps to get 6mm ARC to run reliably. A difference here between Grendel and 6mm is how narrow the neck and bullet are with 6mm, so as it rides up the feed ramp, the VLD-shaped bullets can sit lower relative to the feed ramps and extension teeth, and slam the meplat into the feeding cone cut into the barrel breech.

It looks like Geissele has taken total ownership of those problems with a magazine, barrel extension, bolt, and barrel approach to get optimal feeding under control, which is the right way to approach it. A lot of the industry has been piece-mealing things together relying on others to handle critical component design and manufacturing with a bare bones approach to latch onto trends, because it’s cheaper that way.

When you chamber in a different cartridge, you really need to engineer the system all together to get it to work. It’s not simply a barrel/bolt/mag drop-in all the time.

LRRPF52 said:

I’ve seen some general complaints about LMT QC loosening up, but nothing about critical components failing.

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I won’t say enhanced bolts are failing left and right, but there’s ample evidence that the bolts are prematurely and sometimes catastrophically failing.

LRRPF52 said:

ASC. I shoot ASC 25rd, old CPD, Amend2 polymer 10rd, and whatever I have basically. I de-edge, blend, and polish my barrel extensions and chamfer my ejectors as reliability enhancements. I also use extra power action springs, standard weight 2.9oz carbine buffers, and sealed gas blocks. I like a tight gas system without leaks all over the place.

Geissele mentioned something about changing the geometry of the barrel extension feed ramps to get 6mm ARC to run reliably. A differences here between Grendel and 6mm is how narrow the neck and bullet are with 6mm, so as it rides up the feed ramp, the VLD-shaped bullets can sit lower relative to the feed ramps and extension teeth, and slam the meplat into the feeding cone cut into the barrel breech.

It looks like Geissele has taken total ownership of those problems with a magazine, barrel extension, bolt, and barrel approach to get optimal feeding under control, which is the right way to approach it. A lot of the industry has been piece-mealing things together relying on others to handle critical component design and manufacturing with a bare bones approach to latch onto trends, because it’s cheaper that way.

When you chamber in a different cartridge, you really need to engineer the system all together to get it to work. It’s not simply a barrel/bolt/mag drop-in all the time.

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What do you make of the hardened steel inserts in the upper?

Steel inserts will help with the rigidity of the upper and its service life.

It's mostly a wear thing with the cam pin. They have it on their large frame uppers, too.

Ernest 5.56 said:

What do you make of the hardened steel inserts in the upper?

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I believe Geissele said they were for keeping the cam pin from wearing on the upper.

I’ve never found that to be a problem for me in almost 40 years of shooting AR-15s in high-volume, but I know other companies have done it as well. I personally have polished cam pins before and used roller cams from POF. Can’t say what difference it made. ArmaLite was the first to make a roller cam on the relatively-unknown AR-10A of 1959, which had a smaller receiver set as well.



I’m not sure of they’re referring to the railed steel liners along the charge handle and cam pin path area, or steel feed ramp extensions like DPMS did with the G2. If it’s also feed ramps in the upper, it could be due to EPR projectiles for the 6mm.

There's one DoD customer who bitches about cam pin wear, is how I've understood it over the years.

Bantam1 said:

When my buddy was working at Surefire they built a rig to test 5.56 bolts. They had varying results of "milspec" bolts lasting from 12-25k, some longer. They tried several bolts on the market made of 9310 or other materials trying to find the "best" for something they were working on. Not many went more than 30k according to him. He said the failures were mostly lugs and cracks where they normally happen. He didn't mention any bolts breaking at the cam pin hole. Probably hard to duplicate in a test fixture.

He said the G bolt lasted well over 125k cycles in their rig and they stopped testing. The only other bolt that lasted that long was the HK 416 which is also forged. The "158+" they are using is proprietary to G for now. I think the forging has more to do with it. I'm no simp for Geissele but I picked up one of the BCG's from them on a sale and so far zero issues. The coating they are using seems to handle wear very well. Maybe if/when my JP fails in my 6 ARC I will get one of the G bolts.

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Do you know if the LMT enhanced Bolt was tested as well?

I've talked with John Holliger about those new single point cut Geissele barrels and he had nothing but positive feedback on them.

I'd love to get my hands on one of the 20" GFR 6MM ARC Stratomatch.

TheOE800 said:

I won’t say enhanced bolts are failing left and right, but there’s ample evidence that the bolts are prematurely and sometimes catastrophically failing.

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Odd. Between myself and 2 other guys we have 6 large frame LMTs and 1 small frame LMT gun with aermet bolts. We shoot a lot and haven’t had any problems. These guns span mfg dates from probably 2012 to last year.

I hope the melonited bolt that came in my Seekins rifle holds up as well.

Thats some neat history @LRRPF52 , I assumed POF invented the roller cam pin.

Tictacticaltimmy said:

Thats some neat history @LRRPF52 , I assumed POF invented the roller cam pin.

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Barrett uses a roller cam in their Rec10 too.

Jsp556 said:

Odd. Between myself and 2 other guys we have 6 large frame LMTs and 1 small frame LMT gun with aermet bolts. We shoot a lot and haven’t had any problems. These guns span mfg dates from probably 2012 to last year.

I hope the melonited bolt that came in my Seekins rifle holds up as well.

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I’d say 2022 production are most suspect, into 2023. Basically when all their boomers retired and they hired zoomers.

Obi-WanKannoli said:

Do you know if the LMT enhanced Bolt was tested as well?

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I am not sure. I just don't remember all of the details of every brand they tested and how many cycles they lasted. I just remember the G stopped testing at 125k and nothing else even came close for standard DI bolts on the market at the time.

Tictacticaltimmy said:

Thats some neat history @LRRPF52 , I assumed POF invented the roller cam pin.

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I think Frank filed a patent on it, unaware that it had already been done as early as 1959. ArmaLite even made the clearance cut in the carrier key to allow the round roller cam pin to insert into position in the cam helix.

I remember when Frank sold the cam pin kits, because they came with a relief-cut chromed carrier key. I think he gave me one as a promo at SHOT back around 2010 maybe. He used to have little promo product packets at his booth. 25rd .308 POF mags, .308 roller cam kits, AR-15 roller cam kits, things like that.

I installed it in a Smith Enterprises chromed bolt carrier without FA notches for one of my Retro 605B builds. 605B had the 4-way Fire Control Group.

Regarding AR-15 bolts: ARDEC put out a paper a few years ago about a new liquid burnishing process that doubled the bolt life, even on already-manufactured bolts. They tested M4A1 bolts to 26,000 rounds in high-intensity, high volume, compressed schedules that normally broke the HPT (dumb) bolts at 13,000rds average.

The real main problem with the US Mil-Std required processes is that crazy HPT test for every bolt, instead of batch-testing with destruction and grain structure analysis.

Procurement has never been super intelligent or informed throughout the entire history of US small arms acquisition lol.

Charmingmander said:

Procurement has never been super intelligent or informed throughout the entire history of US small arms acquisition lol.

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The challenge for the US Military is cranking out high volumes of weapons and equipment and holding those items to very high standards. Since we have such a huge military, it is not an easy feat and I recognize that.

Our arctic and hot weather environmental performance requirements are extremely difficult to satisfy from a production standpoint, as are our life cycle requirements. It’s much easier for tiny little countries to purchase a few, high-quality items with tons of help from the US in all the RDT&E.

Look at Colt Canada, the Hk416, 5.56x45, 7.62x51, optics, NVDs, LAMs, armor, and several of the weapons systems developed, tested, and refined over the last 70 years. A lot of the European arms manufacturers have been stamped out by political forces and now rely on the US for small arms, fighters, missiles, and other things they used to make for themselves.

For example, if the UK wanted to produce their own replacement for the L85, do they have the industrial capacity right now to do it?
What about France?

Right now, it looks like the US is making new carbines for the UK SOF (KAC KS-1).
Germany is replacing France’s FAMAS with Hk416F.

Imagine going back in time to the French Army of the Franco-Prussian War in 1870-71, where they had better rifles than the Prussians, but Prussia had superior artillery pieces, and telling the French that a new German State of the future would be building small arms for them 150 years later.

We have the luxury of second-guessing our procurement, whereas other historic major powers are now reliant on their legacy rivals for basic small arms solutions, let alone high-price systems like fighters.

That doesn't really get to the heart of what I meant. You can follow the entire history of US small arms procurement and find example after example of the DoD making idiotic mistakes, asking for idiotic systems, or in the case of the AR15 and AR10, purposefully sabotaging the weapons in an attempt to force their own rifle be adopted.

Some of this was rectified when Springfield Armory was shuttered but not entirely. Some of it is money but much of it is corruption. Not every dumb decision or specification or requirement is due to logistics constraints.

Charmingmander said:

That doesn't really get to the heart of what I meant. You can follow the entire history of US small arms procurement and find example after example of the DoD making idiotic mistakes, asking for idiotic systems, or in the case of the AR15 and AR10, purposefully sabotaging the weapons in an attempt to force their own rifle be adopted.

Some of this was rectified when Springfield Armory was shuttered but not entirely. Some of it is money but much of it is corruption. Not every dumb decision or specification or requirement is due to logistics constraints.

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I agree with that. Especially the ditching of the .276 Pedersen, the whole 7.62x51/M14 fiasco (as much as I love M14s), the criminal conduct relative to the production of 5.56 ammunition for the AR-15 in the early 1960s after sabotaging the guns against hand-select M14s (and still getting beat).

The Modular Handgun System, the M16A2, the SAW, the M60, ditching ERDL for Woodland camo, changes from proven designs in M-1956 to dumbed-down LC-1 and LC-2, the whole HMMWV family of vehicles with stupid huge track width...only holds 4-5 people for M1025 types, etc.

I’m still trying to figure out who Industries for the Blind is after decades of curiosity. Is it some type of mafia front to steer defense dollars into an organized crime family? There aren’t really blind people sewing gear, yet so many of our TA-50 was labeled as such. It’s weird.

When I got my boots at basic and looked at the tag saying made by blind veterans I chuckled. Less than two weeks later I wasn't laughing anymore.

First PX visit I got, I bought better boots on my own dime. Technically you had to have some written bullshit note from a doc but no one asked questions.

Then after I got out someone stole the damn things

How does one pronounce SOCOM?