AR15 Varmint Build 223 Rem VS 6mm ARC

BiggBeans

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Minuteman
Feb 20, 2017
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Wanting to build a mid range semi auto to be used for varmints out to 600 yards. Crows, Prairie Dogs, Coyotes. Have two cartridges in mind. Either the 223 Rem or the 6mm ARC. what would you guys build if this was the main use for your semi auto varmint gun? dont care about 22 nosler, 224 valk, none of those. just asking about these two options.

223 Rem

Pros: pretty easy to find brass, alot of good temp stable powder options, wide variety of bullets available.

Cons: less energy then the ARC, more wind drift.


6mm ARC

Pros: more energy for them pesky coyotes, better ballistics, wide range of bullets to choose from.

Cons: CANT find brass Anywhere, 6.5 grendel brass is hard to find as well, you could convert grendel brass if you find it but have to trim alot, mags seem to be hit or miss. some of the best powders for the ARC are really sensitive to temp like LEVEREVOLUTION and CFE 223
 
Between those 2 and the component shortage I would run 223. With a good bullet choice the 223 can get it done.

I've been on wait lists for ARC brass for a few months now and haven't managed to snag any. Same for grendel.

Also checking on rules and laws where you live for hunting might affect the choice also. Here in south dakota you can critter hunt at night for coyotes and such but you are restricted to 22 caliber.
 
Between those 2 and the component shortage I would run 223. With a good bullet choice the 223 can get it done.

I've been on wait lists for ARC brass for a few months now and haven't managed to snag any. Same for grendel.

Also checking on rules and laws where you live for hunting might affect the choice also. Here in south dakota you can critter hunt at night for coyotes and such but you are restricted to 22 caliber.


I never though about the night hunting thing. Youre absolutely right. I love the 223 for varmints. Just something about the arc keeps bringing me back to it. Might just order the 223 barrel and bolt and put it all to rest already
 
I never though about the night hunting thing. Youre absolutely right. I love the 223 for varmints. Just something about the arc keeps bringing me back to it. Might just order the 223 barrel and bolt and put it all to rest already
Yeah I know what you mean about the 6ARC. I've got half the upper done for myself for one but without being able to easily get ammo and brass for it, I am taking my time to get it done and waiting for sales to pop up to grab things for it.
 
The ARC has a lot of ballistic benefits over a .223 / 5.56 ... but if you can't get ammo or brass, then it is a no go for me.

If there was a reasonably large assortment of reasonably priced ammo for the 6MM ARC, I'd have one already... but most of the limited selection of factory loads.. is $1.50+ per shot, and is closer to $2 / shot.

I don't have as much time to reload for my firearms... so I'd have to hope the only 2 factory ammo choices would shot well in my barrel.... and that RARELY works out.

And that is to bad, I was very interested in the 6MM ARC ... but the ammo / component shortage has killed it.... hopefully only for the time being.
 
I'm shooting both out of gas guns. 223 components are easier to find than ARC. Like everyone else I have been waiting months for arc brass. Just keep reloading the 100 rds I have. So far my 223 setup is in a 22 inch bull barrel in 223 Wylde, jumping 88gr ELD-M's 24 thousandths into the rifling. Getting 1/2" moa at at 100 yards. Using new Lake City brass, bl4 primers and varget. My 9 years old granddaughter can consistently hit 4" plates at 200 yards and 8" plates at 600 yards from the bench. The ARC load development is still evolving. Trying 110 A-Tips now over CFE223 powder. As soon as it settles in I will post it but so far no luck. Personally, I shoot more 223 than anything else. I run both gas and bolt guns in it and you just have to find what load your rifle likes then run with it. Just takes a lot of time to find the right one. Each of my rifles have their own pet load they like. I'm retired so I have a lot of time to mess with them to get each one just right. It takes 3 things to get it right on. Time, money and patience. Like they say, you build it and they will come...
 
A 20”, cut rifled, national match profile barrel chambered in 223Wylde or the CLE chamber from any of the reputable sources fits the bill for the uses you’ve stated.

I’ve been underwhelmed with the 6ARC so far. I should have built another Grendel instead.
 
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I also think you answered your own question. Ive been keeping an eye on the 6 ARC thread and barrels seem to be hit or miss so far. Some great shooters but a fair amount of people saying that they are struggling with it too. 223 would be flatter to right? May be something to consider if you use thermal at night at all
 
The ARC has a lot of ballistic benefits over a .223 / 5.56 ... but if you can't get ammo or brass, then it is a no go for me.

If there was a reasonably large assortment of reasonably priced ammo for the 6MM ARC, I'd have one already... but most of the limited selection of factory loads.. is $1.50+ per shot, and is closer to $2 / shot.

I don't have as much time to reload for my firearms... so I'd have to hope the only 2 factory ammo choices would shot well in my barrel.... and that RARELY works out.

And that is to bad, I was very interested in the 6MM ARC ... but the ammo / component shortage has killed it.... hopefully only for the time being.
Im hoping it will eventually catch on. The benefits that it has when it works does seem to be pretty great past 800 yards
 
I’ve been underwhelmed with the 6ARC so far. I should have built another Grendel instead.
Ballistically? Or otherwise?
I've got a fleet of 223/5.56's, a 6.5 Grendel and a 6mm Grendel and they all seem to fit well in the role I intended. And watching everyone's load data, they're getting pretty much identical velocities with a given bullet weight and barrel length that I've gotten with my 6mmG, to the point I've decided they might as well be the same thing. Which makes sense, .030 shoulder difference isn't much.
 
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....your locales hunting regulations will dictate the caliber you can utilize. That being said, the 6ARC interest is beginning to increase quite rapidly and I suspect ammo & components availability will follow as spring and summer roll around. Despite the smaller reports of less than stellar experiences folks are having, there are a greater amount of positive reports with a wide range of projectiles and powders utilized by those rolling their own, as well as those using the currently limited factory offerings, more so than the 224 Valk experience.
 
The 223 is the easy choice right now. Ammo and components(except primers) are easily found right now for the 223. The 6 ARC does seem like a good cartridge but from what I have seen guys are not getting the speed that they want. I was stuck between the 6 ARC and the 224 Valkyrie and went with the Valkyrie. I’m glad I did because it shoots so well and has less drop and wind drift than the 6 ARC.
 
Ballistically? Or otherwise?
I've got a fleet of 223/5.56's, a 6.5 Grendel and a 6mm Grendel and they all seem to fit well in the role I intended. And watching everyone's load data, they're getting pretty much identical velocities with a given bullet weight and barrel length that I've gotten with my 6mmG, to the point I've decided they might as well be the same thing. Which makes sense, .030 shoulder difference isn't much.
Otherwise.

I changed a couple 223 Wylde barreled rifles over to 6ARC. I didn’t want to hand load another caliber and I figured one of the 3 factory Hornady loads would work in each of the rifles. Both guns were 18”, 1 Proof Stainless, 1 BA melonited stainless. The 18” stainless Proof barrel averaged about 1.25 moa with the 108’s. The other 2 averaged between 1.5-1.75 moa. The 18” Ballistic Advantage barrel shot the 105’s around 1 moa and the 103’s & 108’s averaged 1.5. That’s good enough to hunt with but I kind of expected a lot better from the Proof barrel. Every 6.5 Grendel I’ve had shot the Hornady Black 123 ELD’s under MOA.

We shot a few pigs and it worked fine. All were recovered within a few yards of where they were shot. Farthest one was a 150lb sow at 435 yards. The bullets work fine. No real improvement over a 6.5 Grendel.

The ammo burns extremely dirty. When I pulled the rifles apart to put the 5.56 barrels back, I noticed that the gas tubes were starting to clog up. The Proof barreled rifle had 520 rounds through it and the tube was about 1/4 of the way clogged. I had wondered why the bolt was slowing down and this explained it. The other gun only had 150 rounds fired and wasn’t nearly as bad but was starting to build up as well. Hand loading with a cleaner powder would eliminate this problem, but then you’re back in 6.5 Grendel velocities with 100+ gr bullets.

Oh well, 1st world problems. It was fun giving it a try. I was overall satisfied with the performance on game. I was underwhelmed with the group sizes I was getting at 100 with factory ammo so I never really shot them much farther than 400 yards. I figure the tube would have been clogged to the point that it would have to be changed somewhere between 800-1000 rounds.

Back to 69gr TMK’s and 168gr ELD’s for now. If I decide to stray from 223 & 308 again, I’ll go back with 6.5 Grendel.
 
Otherwise.

I changed a couple 223 Wylde barreled rifles over to 6ARC. I didn’t want to hand load another caliber and I figured one of the 3 factory Hornady loads would work in each of the rifles. Both guns were 18”, 1 Proof Stainless, 1 BA melonited stainless. The 18” stainless Proof barrel averaged about 1.25 moa with the 108’s. The other 2 averaged between 1.5-1.75 moa. The 18” Ballistic Advantage barrel shot the 105’s around 1 moa and the 103’s & 108’s averaged 1.5. That’s good enough to hunt with but I kind of expected a lot better from the Proof barrel. Every 6.5 Grendel I’ve had shot the Hornady Black 123 ELD’s under MOA.

We shot a few pigs and it worked fine. All were recovered within a few yards of where they were shot. Farthest one was a 150lb sow at 435 yards. The bullets work fine. No real improvement over a 6.5 Grendel.

The ammo burns extremely dirty. When I pulled the rifles apart to put the 5.56 barrels back, I noticed that the gas tubes were starting to clog up. The Proof barreled rifle had 520 rounds through it and the tube was about 1/4 of the way clogged. I had wondered why the bolt was slowing down and this explained it. The other gun only had 150 rounds fired and wasn’t nearly as bad but was starting to build up as well. Hand loading with a cleaner powder would eliminate this problem, but then you’re back in 6.5 Grendel velocities with 100+ gr bullets.

Oh well, 1st world problems. It was fun giving it a try. I was overall satisfied with the performance on game. I was underwhelmed with the group sizes I was getting at 100 with factory ammo so I never really shot them much farther than 400 yards. I figure the tube would have been clogged to the point that it would have to be changed somewhere between 800-1000 rounds.

Back to 69gr TMK’s and 168gr ELD’s for now. If I decide to stray from 223 & 308 again, I’ll go back with 6.5 Grendel.
TMKs working pretty well on game for you and have good groups?
 
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TMKs working pretty well on game for you and have good groups?
Yes sir. 69gr tmk’s have the same bc as a 77gr smk and you can push them close to 2900fps from an 18” barrel. It’s easy to get them to shoot under moa from a good barrel. I’ve killed yotes, hogs, and deer with them. For safe kills, keep shots on hogs and deer under 200 yards. They’ll kill coyotes as far as you can hit them.
 
The 223 is underwhelming for all your listed uses. Small for coyotes and slow for blowing up p dogs and crows. That being said, it's still a better round for the p dogs and crows. Maybe I just suck at it but my 223 hit yotes get away too often. I'm talking 1 out of 20. But that's way too often. Went to 243 and ain't looked back.
 
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The 223 is really hard to beat. Just choose the proper bullets and it’s a very versatile cartridge. I personally run 53 vmaxs for prairie dogs and coyotes and have had excellent results. I haven’t had a need to shoot a coyote over 200 yards though so I’m sure that would change things. Prairie dogs I have killed out to 400ish with great results.
 
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I have a 20" lightweight Colt barrel 1-7" laying around so I'll do a cheap build off of that to augment my AR's. Though I love the AR15 platform it's really limited. I'd really like to build a bolt action 223. And since I have 243 win brass/ dies laying around another bolt rifle in that makes more sense than a 6mm ARC. They are cool though, just not practical with short supply of components.
 
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