Anyone actually see these issues with 6mm ARC?

[LRRPF52]

Once I had developed my fundamentals, the idea that I could achieve more, faster, became attractive. If I am trying to win and be competitive, why not use whatever I can as an advantage within the parameters allowed?

Just about two years ago, after I had waited for my buddies to shake things out, I jumped into the world of 6mm ARC. It gave me large-frame ballistics in a small frame. It’s a beautiful thing, in theory. That’s just not how it worked out for me. The 6mm ARC has had more failure points than any other platform I’ve ever used for any reason.

Q: Can you get into some of the issues you were experiencing?

I have had an astronomical amount of carbon buildup that has completely seized my gas tubes in as little as 500 rounds and ONLY as many as 1,000 or so. That has happened consistently every 500 to 1,000 rounds for 8,000 rounds like clockwork for the last two years.

The second issue is the bolt. Generally, the 6mm ARC uses a 6.5 Grendel bolt and extractor, which is inherently frail. I’ve seen a number of, mine included, but other close competitors and friends of mine, snap extractors, crack and blow bolt lugs. Because of the case geometry, feeding of the system itself is not as ideal as other cases are. If I had to summarize, the level of maintenance I have had to put into this system to use it is exhausting. I have to track rounds on my gas tube, bolts, and extractors.

I’ve been seeking the answers to what’s been happening with my equipment and with my buddies’ equipment. There are easily 25,000 rounds between a handful of us on the clock, with 6mm ARC over the past two years. The only data point I can find is how we use our equipment versus others who are not competing with it. I see prolonged life and a lack of malfunctions for people who are hunters or recreational shooters, not “violently” using this platform.

6mm MAX Q&A

Specific problems he stated he and other competitors have experienced with 6mm ARC:

* “I have had an astronomical amount of carbon buildup that has completely seized my gas tubes in as little as 500 rounds and ONLY as many as 1,000 or so. That has happened consistently every 500 to 1,000 rounds for 8,000 rounds like clockwork for the last two years.”

* "Generally, the 6mm ARC uses a 6.5 Grendel bolt and extractor, which is inherently frail. I’ve seen a number of, mine included, but other close competitors and friends of mine, snap extractors, crack and blow bolt lugs.”

* "Because of the case geometry, feeding of the system itself is not as ideal as other cases are.”


The part about gas tubes caught my attention, because I’ve been shooting 6.5 Grendel about 10-20x more than the average shooter since 2009, mostly during multi-day higher volume shoot schedules. I have never seen a clogged gas tube. I’ve been shooting the 12” Grendel suppressed with an adjustable gas system inside the bolt carrier (Bootleg), so that one would see a clogged tube if any of them would, and I’ve been shooting it as my primary Grendel for the past 6 years just to see how it would perform.

I know Grendel has a lot more bore volume than 6mm, so that could be a contributing factory with slower-burning powders and too-short of gas systems.

Has anyone else that shoots 6mm AR or 6mm ARC seen clogged gas tubes?

I would also be interested to see what bolts he’s been using, and what magazines. 6mm has different ogive and neck geometry that is of course smaller, so it might have more of a tendency to hit the edge of the feeding cone inside the breech after passing through the barrel extension teeth.

[Dino11]

I have probably put over 10,000 rounds down range since the release of the platform. One rifle has seen 4000+, rounds through it. Not once has my gas tube clogged on any of the gas guns. What powder are you using, and what load are you loading them with? These two items might help answer your question.

I have never broken a bolt or extractor either, but I never load to or above max load. I find that best accuracy SD and ES are a little below max, and their is no reason to load max with these Secant profiled bullets, they carry their velocity very well down range. So no need to try and hot rod them to shoot farther or get them to open up upon impact on game.

Load information will help answer your question, also what gas block are you using?

[biodsl]

I only have 800 or 1000 rounds down the pipe of my Rebby-spun 16" Lilja. All of it with 105 grain bullets with CFE or Lever. No problems. To be fair, I'm not competing with it. I'm not loading my mags to capacity and runnin' and gunnin'. I'm not trying to eek out the last 20 fps of velocity.

As Grendel owners we know that magazine and feeding is not 5.56 reliable. We tweak and break in our magazines.

Dino's point is well made; there are a lot of questions to be asked of the guy who's breaking a lot of bolts and clogging his gas tube.

EDIT: I just went and read the article from which the excerpt is taken. Sounds like the 6 MAX is the solution to all of his problems. It looks like a step backwards to me.

[Double Naught Spy]

I don't have 6 ARC by was intrigued by the query and so did some googling. Apparently, others are noticing carbon fouling issues, not everyone, but some in the gas tube as well.

https://www.snipershide.com/shooting/thr...y.7129659/

[grayfox]

Aside from it looking like he's promoting/shilling his 6 max, IMO he gives away his real problem:

"Once I had developed my fundamentals, the idea that I could achieve more, faster, became attractive."

Seems to me he is a natural-born hot-rodder/push it to the max/ or over. Why not do it more, faster...??? BECAUSE YOU BREAK THINGS THAT'S WHY!!!!!

My bet is he's essentially trying to make his 6 Arc into a 6 Creedmoor.

I can say that, as mod on the 6 Arc forum, no one has reported or even suggested anything like a gas tube lock-up. Dino summed it up well.

The only gas tube (seeming) "failure" I had was actually a GB that slipped forward, blocking the port and causing leak-off back at the carrier key, and that was a 556. Not the gun's fault, but mine for not securing the GB set screws properly. Found, fixed, running great now.


Edit to add: another guess, but I'll bet he also is falling prey to the "look for swipes, if none then you can push it faster" crowd, basically ignoring that as a mid-pressure cartridge, the typical over-pressure signs for the grendel or 6 Arc are way above Saami max. He didn't "see" any swipes so must not be at or above max pressure yet... not a good way to treat your equipment. My first Eng when in the Nav (nukes by the way) wrote and stressed in his Eng standing orders book, never to stress/over-stress equipment, ie, unless the Russians are shooting at you sort of thing. Stuck with me ever since. Especially b/c more than once, the russkies were in our neighborhood and quiet was much better than fast.

[LRRPF52]

I have probably put over 10,000 rounds down range since the release of the platform. One rifle has seen 4000+, rounds through it. Not once has my gas tube clogged on any of the gas guns. What powder are you using, and what load are you loading them with? These two items might help answer your question.

I have never broken a bolt or extractor either, but I never load to or above max load. I find that best accuracy SD and ES are a little below max, and their is no reason to load max with these Secant profiled bullets, they carry their velocity very well down range. So no need to try and hot rod them to shoot farther or get them to open up upon impact on game.

Load information will help answer your question, also what gas block are you using?

Not me, but the guy in the interview. I haven’t had any of these problems and I’ve been shooting 6.5 Grendel since 2009. I don’t have a 6mm AR or 6mm ARC. I have shot 6mm AR in friend’s guns, but never got around to building one up.

[lazyengineer]

I don't have 6 ARC by was intrigued by the query and so did some googling. Apparently, others are noticing carbon fouling issues, everyone, but some in the gas tube as well.

https://www.snipershide.com/shooting/thr...y.7129659/

Why would that be? Best guess ive got , I suppose the smaller diameter the bore, the slower the powder specified (delta vol increase as bullet travels is smaller, compared to Grendel, so best run with a powder that gives a slower rate of new gas generation). And it's a low pressure round - so.. slow powder plus low pressure I guess means incomplete burn and sooty? Beats me - that's the best I've got. As to the breakage - I read that as him hot rodding the load. I'd love to know his powder and load. And whose bolt he is running.

[Double Naught Spy]

And it's a low pressure round - so.

If low pressure is attained by reduced fuel, that is okay. If low pressure is attained by incomplete combustion, then the result can be a sooty mess and so maybe that is where some folks are having issues?

[Zeneffect]

carbon fouled gas tube after 500 rounds sounds like his rifle is a POS and he needs to re-evaluate the benefits of the lighter spring, choked gas tube, and garbage ammo he is trying to let off at a high rate.

"competition" means a lot of things... with "high rate of fire" this leads me to believe the guy aimed for a tacticool setup rather than a functional one. if dude is breaking bolts, extractors, plugging gas tubes... no need to look further other than his setup is complete dog sh*t and does not represent a typical, functional setup.

Race cars need work after every race, race guns do too. Guy should get with the program and stop complaining and just accept the fact that to be competitive, it requires a lot of work before and after a match.

[LR1955]

carbon fouled gas tube after 500 rounds sounds like his rifle is a POS and he needs to re-evaluate the benefits of the lighter spring, choked gas tube, and garbage ammo he is trying to let off at a high rate.

"competition" means a lot of things... with "high rate of fire" this leads me to believe the guy aimed for a tacticool setup rather than a functional one. if dude is breaking bolts, extractors, plugging gas tubes... no need to look further other than his setup is complete dog sh*t and does not represent a typical, functional setup.

Race cars need work after every race, race guns do too. Guy should get with the program and stop complaining and just accept the fact that to be competitive, it requires a lot of work before and after a match.

ZE:

You got that right about the maintenance needed to keep a truly competitive firearm functioning perfectly for every shot in competition.

The bolt lugs shearing sounds more like he is repeating things that we witnessed fifteen years ago and have since then been corrected pretty well.

I will say this about the 6mm though. You need to keep the thing cleaner than you would a Grendel, 5.56, or a 7.62. That means cleaning it and inspecting for worn parts on the bolt after each match and practice. Not a big deal and you are spending the time to make sure the rifle performs at its peak potential.

LR-55

[Highbrow]

I compete with a 6mmAR. Current Bartlein barrel has over 3500 rounds. Broke an extractor before 1000 rounds but no other issues. Continues to be accurate at 600 yards. Only use Varget and moly bullets. Never crossed my mind to look at the gas tube. Gets cleaned after every weekend match.

[StoneHendge]

I had my 6 ARC go down on me in a practical match Saturday. Bolt wouldn't lock down on a chambered round. The day was over for me and the 2 hour ride home was long. Upon inspection when I got home, the extractor spring had basically failed (maybe kinked a little) and the extractor wouldn't slide up and over the rim on a magazine fed round. A 16" ARC with MLGS takes a lot of extractor abuse. The match is probably as abusive as what these guys do (I've been looking into it and it looks like a lot of fun!) - 2 stages prior to the failure 7 rounds went downrange in 11.09 seconds and 10 to 20 will often go downrange in under 90 seconds. I'm probably going to swap out the extractor and spring every thousand rounds moving forward.