22 Arc

FireFlyFishing said:

Heavy consideration for a 6 ARC for coyotes. The 6/.243 just puts them down so much better than a 556/.223.

I'd rather have a 6CM in a 556 frame, but that won't work….ever. Not thrilled with the ar-10 frame. I have an extra AR looking for a purpose, so I'll settle for 6ARC I suppose. I'm thinking 20" barrel to get some velocity out of it.

I'm not buying the 22-250 velocity out of an AR pitch that Hornady is marketing.

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I don't remember them saying you'd get 22-250 velocities. I recall it was with improved bc bullets it would catch and surpass a tradition 22-250 quickly. I also remember them saying if you had a custom 22-250 with tighter twist barrel it would always outperform the arc.

They said it on one of their podcasts. I don't recall exactly which one, but I remember Seth stating that.

SmokinCrow said:

I don't remember them saying you'd get 22-250 velocities. I recall it was with improved bc bullets it would catch and surpass a tradition 22-250 quickly. I also remember them saying if you had a custom 22-250 with tighter twist barrel it would always outperform the arc.

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The problem with the grendel based cases in an AR is the max saami pressure is lower due to the larger case head diameter being in a standard ar bolt.

Isn't the Grendel case based off of the Russian 7.62x39, which was the parent case for the Russian 5.45x39 chambering in the AK 74? Isn't that Russias answer to the 5.56 NATO round?

DSheetz said:

Isn't the Grendel case based off of the Russian 7.62x39, which was the parent case for the Russian 5.45x39 chambering in the AK 74? Isn't that Russias answer to the 5.56 NATO round?

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Yes but look at a grendel case and then a 556. The grendel casehead is bigger. So when you put the bigger case head in a bolt made for a 556 there is much less meat there for the bolt lugs. Saami max for 22 arc is 52k. By comparison a 556 is 62k.

cajun said:

Yes but look at a grendel case and then a 556. The grendel casehead is bigger. So when you put the bigger case head in a bolt made for a 556 there is much less meat there for the bolt lugs. Saami max for 22 arc is 52k. By comparison a 556 is 62k.

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all the guys locally have switched to the hi pressure bolts which all but eliminated the lug sheer issue and are running pressures in the 60k range without issue. they are saying the lug issue is basically an internet talking point now. my brother is running bolt gun numbers in his AR without issue making info i hear from others more believable.

can1010 said:

all the guys locally have switched to the hi pressure bolts which all but eliminated the lug sheer issue and are running pressures in the 60k range without issue. they are saying the lug issue is basically an internet talking point now. my brother is running bolt gun numbers in his AR without issue making info i hear from others more believable.

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Well there is a reason saami limited the pressure.

I bought the bolt for the Russian 7.62x 39 and the bolt carrier group for it. In my humble opinion comparing the 7.62x39 and the 5.56x45 brass is comparing apples and oranges as they are completely different cases as are the Grendel and the 5.56x45 due to having different parent cases and that was the point of my post. The upper and lower I use is stamped for the 7.62x39 as well. There are so many variables and different cartages that fit into the AR 15 platform and the AR 10 platform. When I take the time and check them out there are a variety of bolts and bolt carrier groups that will fit in the upper receivers for the different cases. For me it pays to look at them and match them to what I am going to shoot mostly for my own safety and anyone around me.

can1010 said:

all the guys locally have switched to the hi pressure bolts which all but eliminated the lug sheer issue and are running pressures in the 60k range without issue. they are saying the lug issue is basically an internet talking point now. my brother is running bolt gun numbers in his AR without issue making info i hear from others more believable.

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I have a lot of experience with the grendel. Yes if you are shooting an enhanced bolt or shooting a bolt action you can push it. But the people making ammo have to load to saami spec. Hence the reason some folks are disappointed in factory ammo.

ARs are a complex mechanical precision piece of equipment, when you go running different chamberings in them don't you also want to look at the buffer and recoil spring system as well as the bolt and bolt carrier group? As with anything else they are an interesting subject depending on how your own interests lay as to how much you want to get into studying and how well you want them to function.

Anyone running the 22 or 6 ARC, is there a consensus on longer than rifle length gas? When I went down the road of building a 6.5 CM AR10, this was one of the things that was really a requirement to not get pressure signs or case head swipes (especially shooting suppressed). I found with the 6.5CM at least a +1 was needed for anything over 18in. It seems like the 6 ARC would be less susceptible because of the bigger bore. Is the rifle gas enough for a 20in 6ARC? What about a 20in 22ARC?

I'm running both. I have a rifle length in the 6ARC with 24" match barrel. I had to install an adjustable gas block and play around with the buffer spring and weight, as it was so energetic the BCG flexed and the gas key crashed into the gas tube and locked the gun up tight just 1 round into my 3rd box of factory Hornady 108ELDM break in ammo. I shoot suppressed which also increases the back pressure. The bolt unlocks before the pressure bleeds off, swiping the case head and sending gas in my face. The 21" 22 arc has an +2 gas block and it's so much easier on me, the gun, and the brass. I wish my 6ARC had at least a +1. YMMV