6mm ARC vs 6mm Max

[Veracity]

Can you give some context to where you've seen dozens of ARC bolts break and got the average bolt life numbers from? Do you work for Geissele or something like that? Also, if you've broken dozens of ARC bolts, it seems like you're pretty well 100% jumped in already.

I have broken 2 personal bolts and 3 extractors, and had a few that weren’t mine fail. ARC has been fairly heavily used in QP and other gas gun competitions since it was introduced, as well as submissions and use in various units and agencies.

As far as not jumping in 100%, I meant by ditching my 223, 224 Valkyrie, 6.5CM and .260’s that I still compete and teach with. I would like to though.

 

[Tex68w]

I love the Proof 6ARC barrels with the heavies (103-108) but I can't get them to group better than 2" with the 80's and it seems to be a pretty common issue not just with Proof barrels but in general.

 

[Macht]

They did not decide that, the new mag is not for a GI-pattern AR.

Is it for that Grendel/ARC Surefire receiver set someone ran at the World Shoot this year?

 

[Gtscotty]

I have broken 2 personal bolts and 3 extractors, and had a few that weren’t mine fail. ARC has been fairly heavily used in QP and other gas gun competitions since it was introduced, as well as submissions and use in various units and agencies.

As far as not jumping in 100%, I meant by ditching my 223, 224 Valkyrie, 6.5CM and .260’s that I still compete and teach with. I would like to though.

Thanks for the info, out of curiosity do you remember the approximate round counts for your bolts when they broke? Also, if you were running reloads, were they something like LVR/CFE223/AA2520, or something like Varget/H4895/AR-Comp? Reason for the curiosity is I've heard a few folks who broke bolts early trying to get up to a decent velocity with temp stable powders like Varget, but I'm interested to hear if folks are breaking bolts early with the powders you don't have to lean on as much.

Might not be the prevailing opinion, but if I can get 2k-3k rds out of a $90 ARC bolt, I'll be pretty happy with that, more is better but for me that is probably good enough. One thing the ARCs and similar cartridges could really use though is basically a temp stable version of LVR/CFE223, I was really hoping Staball Match would answer that need when it was intro'd, but it's a bit too fast to be optimal. Ramshot has impressed me with Grand along those lines for a magnum powder, maybe they could bring out something like a temp stable Big Game, there's no shortage of cartridges that could benefit!

 

[Veracity]

Thanks for the info, out of curiosity do you remember the approximate round counts for your bolts when they broke? Also, if you were running reloads, were they something like LVR/CFE223/AA2520, or something like Varget/H4895/AR-Comp? Reason for the curiosity is I've heard a few folks who broke bolts early trying to get up to a decent velocity with temp stable powders like Varget, but I'm interested to hear if folks are breaking bolts early with the powders you don't have to lean on as much.

Might not be the prevailing opinion, but if I can get 2k-3k rds out of a $90 ARC bolt, I'll be pretty happy with that, more is better but for me that is probably good enough. One thing the ARCs and similar cartridges could really use though is basically a temp stable version of LVR/CFE223, I was really hoping Staball Match would answer that need when it was intro'd, but it's a bit too fast to be optimal. Ramshot has impressed me with Grand along those lines for a magnum powder, maybe they could bring out something like a temp stable Big Game, there's no shortage of cartridges that could benefit!

The JP extractors that have broken on me did it early, 500-800rds.
JP Bolts lasted 1400-1700~ rds
Rexus bolt now has just over 3000

Everything was factory Hornady Match 108 and TAP 106.

Competition barrels have been Proof, Krieger and Bartlein 20" +1 rifle gas, unsuppressed, VLTOR A5, Adjustable GB, 419 brake

 

[Tex68w]

The JP extractors that have broken on me did it early, 500-800rds.
JP Bolts lasted 1400-1700~ rds
Rexus bolt now has just over 3000

Everything was factory Hornady Match 108 and TAP 106.

Competition barrels have been Proof, Krieger and Bartlein 20" +1 rifle gas, unsuppressed, VLTOR A5, Adjustable GB, 419 brake

Really surprised to hear this, have any pics of these failures?

 

[ironhiide]

I'm interested in seeing the broken bolts and extractors too. I'm using Rexus Ultrabolts, 1400+ rounds on a 6 Arc shooting Hornady Black 105gr and maybe 300 rounds through a 22 arc, shooting Hornady ammo as well. The bolt and extractors look perfect after a thorough cleaning I did after my last range trip before xmas.

 

[Cascade Hemi]

I haven't seen dozens of broken Grendel bolts but I have seen a few over the years. There are plenty that come up with a search Google. The Grendel forum has no shortage of broken bolt reports too. I have an AA bolt that the undercut lug has broken off of but I believe it doesn't add support and it is still serviceable.

Rexus has Grendel bolts in inventory at this time. Their bolts are probably better designed than JP.

 

[DeathBeforeDismount]

Im putting together a 6 ARC to play in gas gun matches. 22" Proof barrel with a JP bolt. Gonna run about 1K f Hornady match 108 before messing with reloads. Lets hope my luck is better than yours @Veracity. Parts should be here next week and then verifying BC/dope.

Running a SA AGB and Bootleg carrier with a KGM can. Hopefully I can get the system tuned down to keep pressure on the low end and keep parts malfunction to a minimum. I am going to order a 2nd bolt just incase to keep in match bag. Would suck to deadline in middle of match.

 

[LRRPF52]

Seems like a great way to go for a match rifle is to use the Surefire/Magpul system.

The amount of testing they both did to ensure reliability has taken years, according to both companies.

That Surefire ICAR project started at least 6 years ago.

Magpul said they went through the whole debris, dust, saltwater, extreme cold, extreme heat, drop, feed lip, clearance and tolerance testing with crazy numbers of cycles and refinements to the design before nailing down the molds.

I got a New Frontier Arms billet receiver set and am on notification for the ICAR PMAGs shipping date.

I want a new upper design that is semi-monolithic that has an ejection port door though.

I’m doing Grendel.

 

[Cascade Hemi]

Seems like a great way to go for a match rifle is to use the Surefire/Magpul system.

The amount of testing they both did to ensure reliability has taken years, according to both companies.

That Surefire ICAR project started at least 6 years ago.

Magpul said they went through the whole debris, dust, saltwater, extreme cold, extreme heat, drop, feed lip, clearance and tolerance testing with crazy numbers of cycles and refinements to the design before nailing down the molds.

I got a New Frontier Arms billet receiver set and am on notification for the ICAR PMAGs shipping date.

I want a new upper design that is semi-monolithic that has an ejection port door though.

I’m doing Grendel.

New Frontier used to sell a 6.8 Upper with a dust cover and case deflector.

 

[LRRPF52]

New Frontier used to sell a 6.8 Upper with a dust cover and case deflector.

When I ordered my set from them, they only had that featureless option. I would really like a billet semi-monolithic like a LWRCi with port door and no forward assist, or relocated FA like BCM has done.

 

[Rob01]

Im putting together a 6 ARC to play in gas gun matches. 22" Proof barrel with a JP bolt. Gonna run about 1K f Hornady match 108 before messing with reloads. Lets hope my luck is better than yours @Veracity. Parts should be here next week and then verifying BC/dope.

Running a SA AGB and Bootleg carrier with a KGM can. Hopefully I can get the system tuned down to keep pressure on the low end and keep parts malfunction to a minimum. I am going to order a 2nd bolt just incase to keep in match bag. Would suck to deadline in middle of match.

I plan to get a second bolt just in case also. Not too expensive so better to have it and not need it.

Looks like Coleman’s Creek is doing some Geissele gas gun matches this year starting in May. Also might use it in a few matches at Frontline too.

 

[Cascade Hemi]

I plan to get a second bolt just in case also. Not too expensive so better to have it and not need it.

Looks like Coleman’s Creek is doing some Geissele gas gun matches this year starting in May. Also might use it in a few matches at Frontline too.

Recent Monster bolts are probably the best traditional material bolts on the market.

 

[Cascade Hemi]

When I ordered my set from them, they only had that featureless option. I would really like a billet semi-monolithic like a LWRCi with port door and no forward assist, or relocated FA like BCM has done.

I should have ordered a receiver set years ago but I didn't want to mess with modifying 6.8 mags. Hopefully we'll see someone like Ridgeline offer a semi-mono medium upper. Long loaded 130SMK/TMK/TGK 6.5G pushed to 60k would be the Grendel we've always wanted.

 

[LRRPF52]

I should have ordered a receiver set years ago but I didn't want to mess with modifying 6.8 mags. Hopefully we'll see someone like Ridgeline offer a semi-mono medium upper. Long loaded 130SMK/TMK/TGK 6.5G pushed to 60k would be the Grendel we've always wanted.

It would be nice to have the Magpul boring tool they used on initial testing with Six8 mags, because the Six8 mags are 30rd and 20rd.

The 20rd mag is perfect height for bench. Both have windows.

 

[M4guru]

Magpul only makes a 30, LWRC cuts them down and glues them back together for the shorter one. YMMV on their durability.

 

[DeathBeforeDismount]

It would be nice to have the Magpul boring tool they used on initial testing with Six8 mags, because the Six8 mags are 30rd and 20rd.

The 20rd mag is perfect height for bench. Both have windows.

Have you tried the giessele 15s?

 

[LRRPF52]

Have you tried the giessele 15s?

I just took some dimensions from a Geissele 20rd, but didn’t do any feeding or reliability tests with it.

Keep in mind I just don’t have feeding or reliability problems with my assortment of Grendel mags, so....

 

[LRRPF52]

Magpul only makes a 30, LWRC cuts them down and glues them back together for the shorter one. YMMV on their durability.

So I just went and looked at the 20rd LWRC/Magpul Six8 mag and see exactly what you’re talking about.

They sawed-off the bottom, somehow cannibalized the flared section for the outer floorplate, and also did some machining of one of the internal guide ribs to maybe clear the red, bottom inner spring seat plate.

You can see evidence of the mag window having been clipped off or cut abruptly, rather than terminate normally above the base plate.

I would have never caught that, other than maybe during Cerakote.

 

[WindstormSCR]

What is it for? Hopefully not the old Six8 receivers.

Well this aged poorly

 

[45-90]

I love the Proof 6ARC barrels with the heavies (103-108) but I can't get them to group better than 2" with the 80's and it seems to be a pretty common issue not just with Proof barrels but in general.

Not at all...at least for me, I have 2 Proof SS barrels, not carbon fiber, both are excellent 1/2" 5 shot shooters.

The reason I have 2 Proof barrels is because the BA barrel top and the Proof barrel bottom, both with 108 gr eldm.

On the range the same day, same match ammo, the first 5 shot group ever fired out of the Proof barrel was 1/2" compared to the BA barrels 2.5" group...
So I scrapped the BA barrel and bought another 6mm ARC proof barrel. It too shoots 1/2" groups with heavies including 110 SMK.

 

[Gtscotty]

Well this aged poorly

I tend to question if that's going to turn out to be a good decision now that Geissele has halfed the price of their mags and apparently Duramag is working on kind of a knockoff. I think the upper could be interesting, but I don't see myself going with the oddball lower that only has one mag option over the standard with much improved options.

 

[lonestar1845]

Not at all...at least for me, I have 2 Proof SS barrels, not carbon fiber, both are excellent 1/2" 5 shot shooters.

The reason I have 2 Proof barrels is because the BA barrel top and the Proof barrel bottom, both with 108 gr eldm.

On the range the same day, same match ammo, the first 5 shot group ever fired out of the Proof barrel was 1/2" compared to the BA barrels 2.5" group...
So I scrapped the BA barrel and bought another 6mm ARC proof barrel. It too shoots 1/2" groups with heavies including 110 SMK.

He was talking about the 80 grain bullets, not the heavies.

 

[LRRPF52]

One of the things Geissele did to add to their reliability formula was to extend the length of the trigger guard, with an opening cut for it in the mag well. The trigger guard biases a tilt to the magazine so that the cartridges are always oriented upwards at a specific angle, even when you go magazine monopod.

The Geissele 6 ARC also has a de-edged and blended barrel extension/feed ramps when I looked at it. The bolt does not have radii added for strength at the back of the lug roots or to the sides of the lugs, like Monster and UltraBolts.

The users reported that the 6 ARC Geissle 18” guns are finicky when you switch from 108gr ELD-M to 103gr ELD-X.

The cycling of the BCG in the upper is pretty smooth, not the smoothest I’ve felt, but better than rack-grade ARs.

 

[Tex68w]

Not at all...at least for me, I have 2 Proof SS barrels, not carbon fiber, both are excellent 1/2" 5 shot shooters.

The reason I have 2 Proof barrels is because the BA barrel top and the Proof barrel bottom, both with 108 gr eldm.

On the range the same day, same match ammo, the first 5 shot group ever fired out of the Proof barrel was 1/2" compared to the BA barrels 2.5" group...
So I scrapped the BA barrel and bought another 6mm ARC proof barrel. It too shoots 1/2" groups with heavies including 110 SMK.

You just reiterated what I said about the Proof barrels being great with the 103+ heavy projectiles. You didn't show them being equally as accurate with lighter projectiles so I am failing to see how your experience is any different than mine?

 

[45-90]

You just reiterated what I said about the Proof barrels being great with the 103+ heavy projectiles. You didn't show them being equally as accurate with lighter projectiles so I am failing to see how your experience is any different than mine?

Mine has shot better than 2" groups that you say is a "common issue", with lighter bullets in your earlier statement...didnt say anything about being equally accurate, as you are stating now.

My problem is the velocity is low and they aren't worth messing with over a 223.

So I didn't pursue the light bullets, to find an accuracy load, but this random 70 gr load is capable of 1 MOA for 10 shots. The 58 grs were similar groups were similar but velocity nothing special.
Never shot 80 gr bullets but did try the 87 gr. With 30 gr of CFE223 at 2650 fps my notes say ..."SLOW."
That's just not interesting accuracy or not.

With the velocity the same as the 108 grs with better accuracy and higher BC why bother with light bullets. It was designed around heavy bullets with its fast twist rate, so it's likely not to be as accurate with the light bullets...as shown on target, but its acceptable with the few I've tried and will hit half to 3/4 moa with just 5 shot groups in my Proof barrels.
Which have done less than 2" 5 shot groups with every bullet I've tried...so I do not know of others experiences or if that's the consensus...just my experience.

If you're gonna shoot light bullets just shoot a 223...was my take, after testing a few light bullets in the 6 ARC.

 

[Tex68w]

Mine has shot better than 2" groups that you say is a "common issue", with lighter bullets.
My problem is the velocity is low and they aren't worth messing with over a 223.

So I didn't pursue the light bullets, to find an accuracy load, but this random 70 gr load is capable of 1 MOA for 10 shots. The 58 grs were similar groups were similar but velocity nothing special.
Never shot 80 gr bullets but did try the 87 gr. With 30 gr of CFE223 at 2650 fps my notes say ..."SLOW."
That's just not interesting accuracy or not.

With the velocity the same as the 108 grs with better accuracy and higher BC why bother with light bullets. It was designed around heavy bullets with its fast twist rate, so it's likely not to be as accurate with the light bullets...as shown on target, but its acceptable with the few I've tried and will hit half to 3/4 moa with just 5 shot groups in my Proof barrels.
Which have done less than 2" 5 shot groups with every bullet I've tried...so I do not know of others experiences or if that's the consensus...just my experience.

If you're gonna shoot light bullets just shoot a 223...was my take, after testing a few light bullets in the 6 ARC.

Some guys like the idea of a lighter bullet for a coyote round, that's the entire reason for the ELD-VT. They can have the same gun for different game instead of having multiple guns/calibers for small to medium game. The 80's overwhelmingly create feed/ejection issues and shoot well north of 1" groups as noted in this forum (mine shot close 2" or worse) and on other social sites that discuss 6 ARC. Personally I don't care about hunting coyotes with the 6 ARC all that much nor do I keep furs so if I hit them with something larger and more damaging it's no sweat off my brow.

It's good to hear that some have had success with the lighter bullets in their gasser, but it's certainly not what I would consider the norm. IME, with factory ammo, the 6 ARC is slow across the board, I expected more velocity when I got into the cartridge but for the way that I use 6 ARC, the 108's have been great and of much success on medium game so it'll stay in my rotation for some time to come.

 

[WindstormSCR]

I tend to question if that's going to turn out to be a good decision now that Geissele has halfed the price of their mags and apparently Duramag is working on kind of a knockoff. I think the upper could be interesting, but I don't see myself going with the oddball lower that only has one mag option over the standard with much improved options.

I think it's a question of reliability vs ammunition pickiness and multi-cal capability. I have no doubt that once the ICAR and other 6.8 rifles hit the market we will very quickly see additional magazine options from the usual suspects

 

[Gtscotty]

I think it's a question of reliability vs ammunition pickiness and multi-cal capability. I have no doubt that once the ICAR and other 6.8 rifles hit the market we will very quickly see additional magazine options from the usual suspects

Possibly, but by all accounts the Geisseles are reliable now, available in multiple sizes now, and are no longer crazy priced, especially if you have a ton of regular lowers laying around like me the math of setting up new lowers and buying new mags for a little less than what the Geissele mags are doesn't work out. Even if you don't mind getting into a specialized lower, it's hard to see the benefit I'd be getting. All that said, I actually haven't had problems from regular Duramags and even most of my ASCs, so kind of theoretical for me.