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Custom AR Barrel Manufacturers (6 ARC)

alamo5000

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Minuteman
Jun 18, 2020
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I am looking for a barrel for my new 6 ARC build. Normally with all my other stuff I just use off the shelf components for ARs (because there is so much variety out there) but on this one the pickings are pretty slim.

I have never had a custom barrel made (for anything) so I am unfamiliar with many of the names and quality they are known for.

McGowan, X-Caliber, Mos Tek, and a few others come up when I search... and a few have options more for what I am looking for. Some have wait times up to 10-12 weeks or even 6+ months...

Seeing how off the shelf parts (to get me started in the cartridge) are hard to come by I am strongly considering putting in my order somewhere and just waiting it out.

I just don't know where and what all my options are and who to gravitate towards or stay away from as far as name brands are concerned.

I have an idea of what I am looking for in the way of a barrel, but I simply am not well versed in the barrel manufacturers by brand name.

PS: What I am looking for is a 22" long 6mm ARC barrel, prefer a rifle gas, but might consider +1. I do not want +2. I plan to use an adjustable gas block just because I want that ability to tune because once I am dialed in I will shoot suppressed 99% of the time. I would prefer the gas journal to either be .750 or .875 because I don't want to risk having fitment issues with the gas block fitting under the rail. I would like a matte or a nitride finish as well as a DMR or a modified DMR type of contour (with flutes). Basically I want the barrel to step down in size and be fluted to save weight.

Also if possible I would like a 1:7 twist but if need be I can live with a 1:7.5. Reason for this is I want to have the option to shoot heavy for caliber bullets (IE 115 grain). Basing things off the Berger stability calculator 1:7 would be a bit better of a fit however that said many many reports online show no adverse effects of using a 7.5 twist.

I have found a few manufacturers that can make what I am looking for but I simply don't know anything about them as a company or what type of products they put out.

I don't want to pay $1000 bucks for a barrel but $500-$600 I could do with no problem. I would rather pay a bit more if the end result warrants it.
 
I've currently got two McGowans (223, 6.5G) that I'm very pleased with and two X-Caliber (223, 6mm G) that I'm very happy with. McGowan is more flexible with custom contours. Neither will do nitride last I knew. Had a BHW I didn't have good luck with.
 
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I've currently got two McGowans (223, 6.5G) that I'm very pleased with and two X-Caliber (223, 6mm G) that I'm very happy with. McGowan is more flexible with custom contours. Neither will do nitride last I knew. Had a BHW I didn't have good luck with.
If McGowan works well then I have no problem going with them. X-Caliber as well. Nitride is an option but not mandatory.

My main problem is when it comes to these names I am just completely unfamiliar-- and I would rather have what I want than go through 2-3 things that I don't.
 
I've currently got two McGowans (223, 6.5G) that I'm very pleased with and two X-Caliber (223, 6mm G) that I'm very happy with. McGowan is more flexible with custom contours. Neither will do nitride last I knew. Had a BHW I didn't have good luck with.
I also see lots of debate or rather reports on the other thread about +2 gas systems. I don't understand why this is even a thing. I don't know why a regular rifle length isn't just fine. I could MAYBE see why a +1 would work ok but again, I don't get it (the reasoning behind it).
 
If you're all about shooting groups you can hedge your bets by stretching the budget a little and getting a Craddock Bartlein or something, but if reliable sub moa accuracy is acceptable then the two companies I mentioned will easily meet or exceed that.
+2 gas exists because the lower pressures at the gas port reduces wear and tear on parts and brass and can reduce recoil, and on large frame guns in hotter cartridges it can be almost necessary. There can certainly be too much of a good thing though.
I went +2 on my 22" 6mm Grendel, which is pretty much a 6ARC and I wouldn't recommend it to someone else unless they are like me and have made it life goal to tinker with guns to get the lowest recoil possible. It's 100% reliable now but it took some experimentation with springs, buffer weight, gas tuning and powder used to get it there. It's not the easy button. But boy is it soft now.
Here it is banging the 10" plate at 500yds, I'm pretty much free recoiling it (hence the blinking, I don't typically free recoil and it was disconcerting at first) and it still barely moves.
 
Also, if Rainier gets into the 6ARC game (maybe they already have?) I would definitely take a look at them. They normally have something in their Ultramatch line with specs similar to what you outlined.
 
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Also, if Rainier gets into the 6ARC game (maybe they already have?) I would definitely take a look at them. They normally have something in their Ultramatch line with specs similar to what you outlined.

They posted a teaser months ago when they were contemplating doing a run of them. I think they had 4 made for T&E, but I haven’t seen anything lately.
 
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If you decide to go with Craddock best be prepared for a six to eight month wait.
Yeah I know. That's what kind of has me irritated a bit. I don't mind paying for quality but waiting the equivalent of an NFA wait time for a barrel is crazy. Hopefully something pops up so I can jump on it. As of right now I am considering McGowan. That said I've never done a custom barrel before so I am hesitant in some regards.

They posted a teaser months ago when they were contemplating doing a run of them. I think they had 4 made for T&E, but I haven’t seen anything lately.
I didn't know Rainier was 'thinking' about it. Maybe I can ask some contacts if it's still in the works.

The problem now is barrel manufacturers can run a pallet full of regular AR barrels and they will be sold before the end of the week. From a plain old business perspective in a market like this trying to do runs of 'new' cartridge barrels doesn't make a lot of sense.

Don't get me wrong, eventually ARC barrels will be in stock all over the place like Grendel barrels or maybe even 300 BLK barrels. Right now though the ARC hit the market right at the right time to get caught up in insanity.
 
I talked to the guys at McGowan today. I am leaning towards them at the moment. It will probably be towards the end of the week or so before I make a final decision.

That said here are the specs I want. Please try to poke holes in my theoretical barrel layout because after all it is a 2.5 month long wait and this is my first custom barrel.

The whole purpose and intent behind this rifle build is purely for target shooting and some of it (or a lot of it) at longer ranges. My longest spot available at the moment is 1,400 yards but I can't rule out finding more real estate in the future. Rarely will hunting be involved. Also I want the option to shoot heavier for caliber bullets like the 115 DTAC or even some 109 and 110 grain bullets or whatever else might come to market in the future. Berger and Sierra both recommend a 1:7 twist for their heavier bullets (so that explains that choice).

I will shoot suppressed almost 100% of the time.

  • 416R
  • Either 22" or 24". I am leaning towards a 22" but 24" is not off the table. Now that it's a realistic option I am wondering the downsides to either/or.
  • Modified Hbar profile. He said in 22-24" lengths the 'modified' vs the traditional Hbar is about 1/2 pound lighter and in this caliber it won't make that big of a difference profile wise because it's not some bigger magnum type caliber with excessive recoil.
  • Either a rifle or rifle +1 gas system. I will use an adjustable gas block. He said the +1 would make the gun have a little less recoil but I am not sure 'how much less' that really means. Maybe someone here can quantify it for me.
  • .750 gas block. This is because I do not want any clearance issues fitting it under my handguard (which I already have).
  • 11 degree crown with 5/8x24 threads
  • Matte finish
  • 6 straight flutes. This isn't mandatory but I am thinking it could bring the weight down even a little bit more without giving up too much stiffness. Again if I was shooting a huge magnum caliber I would probably pick a different profile. I am however not so sure about the flutes on the given profile I am talking about. Flutes are not mandatory but I am definitely open to it if it will play nice with the profile.
  • 1:7 twist as mentioned above.
Please add thoughts, ideas, comments, questions, or anything else you would like. I am curious to try and run this through the feedback machine.

Edit: the lower I have and will be using for this has a H1 buffer in it. I am not sure if that will make any difference. I prefer not to switch it out but if I do need to I will.
 
I won't poke any holes in your choices, nothing about them sets off any red flags, but I'll mention some things from my experience since I have a similar barrel. Just as an extra data point.

My 7.7 twist stabilizes the 110 SMK and 112 Matchburner at 900'ish ASL and 2630-2700fps.

Some bigger profile handguards, Seekins, old style Aero, JP etc. will easily fit a .936 gas block. Not sure what you already have though.

If +2 gas is functional unsuppressed, it'll definitely work when suppressed 100% of the time. I wouldn't shy away from at least +1.

For a dedicated target rifle that won't be carried very far, don't be scared to end up with a heavy pig. There's something pretty magical about watching holes appear in paper at 100 yards.
 
I use Cross Machine Tool for all of my ARs and this time I got a matching set, not just of the upper and lower but also the hand guard.

I'm pretty sure I could fit an adjustable gas block in there up to .875 but I'm not sure about the 9. That said I'm not 100% sure if the .875 would have clearance. I think it would but I'm not sure. I plan to use an SLR adjustable block but if I go non adjustable I can for sure fit them in there.

These "+" gas length are new to me so I am kind of risk averse about the whole thing.

I'm not hell bent on a particular twist rate but rather just going with 7 because I would rather be on that side of the line because it could open up some options maybe.

Anyway I was just hoping to get a few opinions, maybe a look with a new set of eyes or something so I don't leave anything out or add something that I don't need in there.
 
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I have more questions. This time in a general sense.

If I go with the modified HBAR (the very top one) vs the regular HBAR (2nd one) in a 24" length would this have any noticeable difference in the real world? I am specifically talking about rifle length gas then stepping down to .750 for the gas block and forward.

I cross referenced and X Caliber offers something similar in a 24" barrel as one of their standard options so I know it will work, but I am wondering what the real world could show as far as results go.

If I was shooting a 300 RUM or something else with huge recoil I can see bigger being better but I am just walking through my options before putting my cash up. (First time buyer so I am naturally over thinking it)

The whole contour thing makes sense when you go rediculously small (IE pencil barrel etc) but on the bigger barrels I am not certain what to make of them all.

ar15_contours.png
 
If I go with the modified HBAR (the very top one) vs the regular HBAR (2nd one) in a 24" length would this have any noticeable difference in the real world?
but I am wondering what the real world could show as far as results go.
Shouldn't be any measurable performance difference. MAYBE if you like to do mag dumps right before you shoot groups. Other than that it's just extra weight.
 
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But you can also spec whatever contour you want, no need to buy off the shelf..
 
Those are the profiles available from mcgowan. I'm still over thinking what's already out there. I would go crazy if I tried to spec out every bit of it.

Based on your response I think the modified is fine. I don't plan on any mag dumps at all. This is purely for leisurely shooting at far targets.

I tried a friend's heavy barrel upper once and I can recall hating that thing. It was a beast so I want to get enough weight but not something nuts. Trying to find that sweet spot.

On other rifle builds in the future I might do something completely different but for this I don't want an insanely heavy barrel. Enough to get the job done and that's it. I might shoot a couple hundred rounds in an afternoon maybe but that would be on the high side of things.

It's more of a plinker than a blaster.
 
Shouldn't be any measurable performance difference. MAYBE if you like to do mag dumps right before you shoot groups. Other than that it's just extra weight.

Custom barrel on order as of today.

6mm ARC
24" modified Hbar with 6 flutes front and back
416R
1:7 twist with 6 grooves
Rifle gas length
.750 gas block
Matte finish
5/8 x 24 threads

Ordered from Mcgowan.

I hope she's a shooter.
 
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If all goes well I should have it in hand around April.

I ordered an SLR adjustable gas block and gas tube as well.

I pretty much have everything I need except for the optic and mount.
 
If all goes well I should have it in hand around April.

I ordered an SLR adjustable gas block and gas tube as well.

I pretty much have everything I need except for the optic and mount.
...here's some pics I have of the SLR Sentry 7 series gas blocks on a BA 18" barrel (rifle gas) using the 13.7" CMT UPHR Mod2 handguard. The clamp on version is the previous gen model and the set screw one is the current gen model. YMMV
 

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Call GA precision. I’ve seen two of their arc barrels shoot, close to the specs you mentioned and the price was less than I expected.
 
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I'm a fan of SLR. I have three rifles all cross machine tool and SLR hybrid with some CMC sprinkled on top. So far everything has SLR blocks under SLR rails.

The CMT rail definitely has enough space under there for the .750 block. The .875 would cut it close but still might fit.

As far as switching now it's too late as far as I am concerned. I looked at GA's site and didn't even see AR barrels listed. I've read up for about a month or more and chose the best one that didn't have a six month or longer wait list.

It's my first custom barrel of any type but I have a feeling it won't be the last, especially once I get into bolt guns.
 
Truthfully I don't know much about custom barrels. Just enough to ask the right questions. You could have the best blank money can buy but a crappy machine operator can mess it up forever in two seconds or less.

Usually when I buy stuff I do something akin to the Barney Stinson crazy hot scale. I look for stuff that is above the line so to speak. Not over priced but provides good results.

I could have paid more for a barrel, maybe even double if performance warranted it. That said there is a lot to be said about a 6 month wait.
 
Too late now but there's these guys.
 
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Another barrel option is BSF Barrels (https://www.bsfbarrels.com/).
They are chambering barrels in 6mm ARC.
I am very happy with mine in 223 Wylde, so I have one on order in 6mm ARC.
(to save a few dollars, you may also want to look into their "test-fired" discount.)
I'm far from an expert on these matters, but my sample of one is pretty sweet.
Several lengths available. Definitely under the one grand price point!
 
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Another barrel option is BSF Barrels (https://www.bsfbarrels.com/).
They are chambering barrels in 6mm ARC.
I am very happy with mine in 223 Wylde, so I have one on order in 6mm ARC.
(to save a few dollars, you may also want to look into their "test-fired" discount.)
I'm far from an expert on these matters, but my sample of one is pretty sweet.
Several lengths available. Definitely under the one grand price point!
I did look at them for sure but I decided against going with a carbon fiber barrel. I have never shot a round through any carbon fiber barrel so they might be great but I would want to do a lot more research before going into unknown (to me) territory. Sorting through all the names of manufacturers that I wasn't that familiar with was a chore enough.

Once I see how this custom one that I ordered goes I might be game to experiment later on.
 
Too late now but there's these guys.
I saw their web page but once again my lack of knowledge regarding manufacturers made my choices a lot harder than it probably should have been.
 
Hope this isn't considered a necro, but was interested in results if you got your barrel yet. I was looking for something reasonable to put on an AR without going too deep in the pocket. I'm most likely going to a bolt system in the future but a heavier barrel is in my future. Also would like to hear more of your gas system choice, not that I'm being critical in any way, just curious about RLGS vs any plus for the 24"