I plan to slap an 18" barrel in a thermal topped LMT MRP-L for predator use (mostly coyote) out of a tripod. I understand the ballistic benefits of the 6 ARC and it definitely has my eye but the additional cost and hassle of the added bolt, finicky mags and harder to find and pricier ammo give me pause. Do those drawbacks outweigh the ballistic benefits? Most of my hunting will be well inside of 600 yards which makes me second guess stepping away from 223/556 for this use case. No BCG swap, cheaper and much easier to access/acquire ammo, and it uses standard mags that I have aplenty. Accuracy is as good as 6 ARC if not better even if it doesn't buck the wind as well. I am just curious if the juice is worth the squeeze when it comes to the caliber?! Any insight from those that have made the switch to 6 ARC please chime in with your findings and opinion.
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18" 6 ARC vs. 18" 223
- Thread starter Tex68w
- Start date
I considered it recently for a nighttime coyote gun as well. Mine is a LMT MRP as welI. I will use a PVS-24 clip-on with a 3-12x56 or Reap-IR thermal for optics and most of my shots will not exceed 300 yards on the east coast. I decided to stay with 5.56 as it does very well within that range killing coyotes with the 53 V-max. I have a ton of reloading components for 5.56, the LMT bolts seem to last forever, my 5.56 ARs have been extremely reliable, soft shooting, and I have less concern for damaging the WP PVS-24 tube.
I also have a LMT MRP-H in 6.5 CM should I feel the need to stretch the legs. Albeit heavier than a 6ARC, with the 22" Proof Carbon 6.5CM barrel, it's not that bad. We do have some land in CO that does have much longer range opportunities and this gun should work well day/night for that use.
I did decide to pick up another 18" 5.56 barrel. I decided on one of the Boss firearms D. Wilson modded Proof Carbon 5.56 18" barrels as the 6.5CM barrel has been very accurate. I also picked it up on sale recently during the holidays for a very reasonable price. I am waiting until after coyote season to install and work up loads for it however. It should lighten the load a little as most of the time this gun has the PVS-24 and a 3-12x56 on it. The LMT 18" SS barrel it wears now has been very accurate shooting the 53 V-max.
I also have a LMT MRP-H in 6.5 CM should I feel the need to stretch the legs. Albeit heavier than a 6ARC, with the 22" Proof Carbon 6.5CM barrel, it's not that bad. We do have some land in CO that does have much longer range opportunities and this gun should work well day/night for that use.
I did decide to pick up another 18" 5.56 barrel. I decided on one of the Boss firearms D. Wilson modded Proof Carbon 5.56 18" barrels as the 6.5CM barrel has been very accurate. I also picked it up on sale recently during the holidays for a very reasonable price. I am waiting until after coyote season to install and work up loads for it however. It should lighten the load a little as most of the time this gun has the PVS-24 and a 3-12x56 on it. The LMT 18" SS barrel it wears now has been very accurate shooting the 53 V-max.
Even inside 400 yards 6 ARC impacts way harder than 223 and it only gets more dramatic the further out you push them. Accuracy will come down to the quality of the barrel and ammo you feed it with either of them, if anything ARC is probably inherently more accurate due to case design.
6 ARC is the superior round. No you won’t find it on most local shelves like 223 but unless you’re looking for ball ammo or some random $30/box varmint express or something you won’t find the 223 ammo you typically want anyway so it’s really a moot point. Comparing quality 223 to 6 ARC the price is the same. I wouldn’t let a bolt or some $15 magazines deter me from it, it’s not like you need 50 magazines on standby for a coyote rifle.
6 ARC is the superior round. No you won’t find it on most local shelves like 223 but unless you’re looking for ball ammo or some random $30/box varmint express or something you won’t find the 223 ammo you typically want anyway so it’s really a moot point. Comparing quality 223 to 6 ARC the price is the same. I wouldn’t let a bolt or some $15 magazines deter me from it, it’s not like you need 50 magazines on standby for a coyote rifle.
Inside of 600y .223/5.56 is the probably the easy button. 6Arc has a ballistic advantage but inside of the range perimeters you’re suggesting it’s going to be a marginal gain for the vast majority with the exception of some extreme conditions.
Additionally 6Arc has some mathematical gains in the terminal department as well you may want weight, though again a .223/5.56 with the right loading is certainly capable.
Additionally 6Arc has some mathematical gains in the terminal department as well you may want weight, though again a .223/5.56 with the right loading is certainly capable.
D. Wilson converted 18" Proof Carbon is the way I was leaning as well. Which can are you running on that setup?
Agreed, the 6 ARC is the ballistically superior round. I'd love to take the leap, just trying to figure out if the juice is worth the squeeze and you make some fair points. If I had a bunch of 77 gr or a large amount of lighter varmint loads lying around in 223 it would make this decision a lot easier. Odds are a few hundred rounds would cover me for the first few years if I am being honest with my shoot/hunt schedule.
Yea it appears to be splitting hairs for my proposed distances since 223 is the much easier round to get your hands on.
I use both but I take the 6 arc out a lot more than the 223. I have had zero runners with the 6 arc. It just hammers them. Bullet drop between the 2 inside of 400 yards isnt different enough to matter but wind drift is definitely less with the arc. I’m hoping to see the new Hornady 80eldvt ammo hit the shelves soon. That stuff should be the ticket for thermal coyote hunting.
I've got a pile of 77gr match ammo, identical Seekins DMR's in 223 and 6 ARC and a twin pair of Larue 223's. One of those Larues is being sold to a buddy, the other converted to a light 6 ARC for hunting and I'm buying more ARC ELDX ammo. All after having my ARC to the range a total of 5 times now. For me it's a game changer.
- I haven't had a runner yet with the 6 arc, all been dead on impact. Can't say that about my 223.
- Mags aren't finicky, but I test them at the range before use (for any caliber). my brother had one mag related issue and he just tossed the mag. they're cheap.
- I can find 108 ELD Match ammo for $22/box, is the same quality ammo for 223 really cheaper than that? Buy it in bulk and dont worry about searching for it.
- IMO the juice is worth the squeeze. I never shoot my 223, just keep it around because everyone should own one and I have a ton of ammo for it.
Man, I'm usually the first to extol the virtues of 223, but if I wanted something dead out to 600 yards I'd have to go ARC.
Loading 65g v max for my 6 arc there isn't really anything a 223 can do that it can't. As far as extending PBR zero due to velocity. Unless you don't reload. Is there any 6arc ammo with lighter bullets available?
If I was grabbing an ar15 to call coyotes it would be my 20 practical.
If I was grabbing an ar15 to call coyotes it would be my 20 practical.
There are smaller places that load down to 58gr. Can't remember the name of the place but have been considering grabbing some. I think stated velocity for 18" was 3350 or so.
I have not replaced my LMT 18" barrel with the Proof 5.56 barrel yet. Waiting until coyote season is over to make the change. I have the Dead Air Nomad-30 on the rifle now and will use it with the Proof barrel when installed.
The LMT MRP-H with Proof 22" 6.5CM barrel has a Dead Air Nomad-LT can on it.
My Seekins loves the 58 VMAX and A2230
18” McGowen 1:7.5
Magnetospeed V3
Hornady 58 gr VMAX
A2230
Hornady brass x 5
205M FGMM
BTO 1.6650
COL 1.4900
32.2 3468, 3466, 3474, 3476 SD 4.6 0.5” no pressure
32.5 3507, 3506, 3497, 3506 SD 4.6 1” mild pressure
Damn that’s cooking. Would love to get 3400 out of my 16” so might have to try that.
Does the gas block tuck under the rail or does the leading edge stick out at the front edge on the MRP-L?
Ok so regardless of 223 or 6 ARC, the rifle length and rifle +1 will have the gas block protruding out from underneath the rail. Thanks for the visual.
Depending on where exactly the shoulder of the gas journal of a RLGS ends up in relation to the rail, an exposed gas block/AGB of the right type could look and work out pretty sweet. I hope you keep us updated on what you end up doing.
I am leaning heavily towards a 18" Proof Carbon in 6 ARC at the moment. I might have already ordered the bolt and mags as well lol.
I've actually got a few like that, only the bottom one done intentionally. The look has grown on me.
What size mags are you gents using? My issues with 6.5G only crept up once using mags larger than ~17rds. Basically, any mag that starts to get some significant curve to it seems to increase the chances they won't run in someone's gun, but the straight-ish mags all seem to run just fine. No scientific study behind it, just anecdotal observations from shooting 6.5G for years and following it (and now the ARCs) on forums.
I have 10’s and 20’s. The 20’s have a slight curve and have been fine except they only hold 19 rounds, not 20. I had issues with 6.5 Grendels with the longer mags too, I just don't use them because I don't see the need with a precision rifle and the length can get in the way too.
I ordered 10 round Duramags, I just can't get with the longer curved AK looking things. For a rifle that'll likely live out its life mounted to a tripod waiting for dogs to get called in the 10 rounders will work just fine.
I am currently shooting a 20" 223 for coyotes. I have had 3 runners inside the 250-400y range with 55g Sierra at 3100fps range. My 6 ARC 18" upper will be fully assembled tonight and I will be running with with the thermal from this point on. The wind drift and Max Point Blank Range on coyote carries me to 387y with a 100y zero and 75gr Max hand loads. I was figuring an 8" kill zone and a coyote should be 11". I have 5 different powder charges to test for the AR on the 75gr before I turn out a bunch of them.
Where does the gas block sit in relation to the rail with the 6 arc rifle +1?It has begun. 18" Proof Carbon 6 ARC.
It's a Rifle +1 so an inch further forward than your 18" 223 Carbon you showed above?!
In all honesty @ToKeepAndBear I imagine it'll be completely in front of the end of the rail by 0.10" or so based on the barrel profile diagram. The rail is 13.25" long and the gas journal area for the Rifle +1 starts at 13.282". It'll have a bit of a Mk12 look to it.
This is so easy...
I am putting this gun together starting with a LMT MARS-L MRP rifle. It has the standard carbine length buffer tube/system. I am considering a longer stock like the Magpul PRS, UBR or B5 Collapsible Precision stock. Do y'all recommend I move to the A5 system with the barrels Rifle +1 gas tube and if not which weight buffer do you suggest?
Well I ended up going the 6 ARC route and here she is folks. The Rifle +1 length gas system has it looking a tad Mk12 like but I am ok with it. I am still waiting on the Geissele SD-E trigger and for my AAC SDN-6 to get back from Echo Machine for the HUB conversion, but other than that the 6 ARC is done.
- LMT MARS- L MRP
- Proof Research Carbon 18" 6 ARC barrel 1:7.5 twist Rifle +1, D. Wilson LMT Barrel conversion w/SLR Micro Gas Block
- Rearden SPB .375/HUB
- JP Enterprises 6mm ARC Bolt
- Night Force ATACR 4-16x42 Mil-XT
- Reptilia AUS 34mm 0 moa
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