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New 6mm Advanced Rifle Cartridge
- Thread starter Gtscotty
- Start date
Joe Carlos writes about the advantages he found testing every AR barrel he could find. He talks extensively about gain twist rifling in this article. I’m drinking the Kool-Aid and ordering a gain twist to help with the pressure reduction he talks here for my 6mm ARC build I think every little bit helps. https://www.thefreelibrary.com/Barr...+2:+how+barrel+characteristics...-a0500072772
Compass cut a Douglas 20” H-bar for me with their chamber that shoots 10-shots 5/8”to 3/4” groups @100yrds about every time. 75gr A-Max 23gr of Varget .003 neck tension. They do outstanding work now I need to narrow down what to order. Thank you, I want something that shoots the factory ammo excellent. Are you using an adjustable gas block? I was thinking of going 22” long +2 gas length with a non-adjustable(one less thing to break of play around with). How does the brass look?
How does it shoot? Thoughts on the gain twist? I got my 6mm ARC barrel from Craddock before Paul started offering gain twist in the Bartlein. He has done gain twist barrels in other calibers (224 Valkyrie) that were tack drivers. I am very interested in going that direction on my next one.
Haven’t installed it yet. Been busy wearing out the Creedmoor.
Should have it complete & first rounds down range by 10/22
Yes, I'm using an SLR adjustable gas block and an Omega 300 suppressor. I'll have to take a picture of the brass, but other than being dirty there are no signs of abuse. I don't use the Crane o-ring on the extractor and radius the edge of the ejector, which both help eliminate damage to the brass.
Nothing I have noticed so far, but I also don't try to smoke my barrels for a heat shift test. When I shot for a group and chrono test I had the Magnetospeed hanging on the barrel and the barrel was fairly warm after a 10 shot string. It cooled for the time it took to drop the mag and load 5 rounds. My POA didn't shift from my zero.
Odin Works 18” with BCG and gas block/tube is a good candidate. Mine is sub moa out to 200yds (the longest range I have) with all factory loads except the TAP.
6mm ARC | 18'' XL Rifle | Barrel w/ BCG | Shop Now
Upgrade your AR-15 with high quality American manufactured parts. Fully built rifles, complete uppers, barrels, forends, and many other accessories. ODIN Works is your main supplier for made in the USA rifles and accessories. Shop now!
www.odinworks.com
I’ve never seen a Criterion that wasn’t good. My one Douglas is excellent but a bit more money. Yotesniper66 has a Dtech Shilen that shoots factory ammo outstanding. Compass Lake has Criterion & Douglas barrels very reasonable that I’m sure you’ll like.
AR-15 Custom Barrels
_ The barrels that I produce all start life as a Shilen blank. We have three main, stock profiles, but custom contours are also available. Shilen offers two lines of stainless steel barrels:...
www.dtechuppers.com
Just got my 18” Proof stainless barrel. I’m running an adjustable gas block and 5.5-30x Burris on it. Deciding what muzzle to get. Thinking area 419 or APA.
Precision armament is worth a look. I've got several of the Hypertap's including on 6ARC. Very happy with them. Back blast at the shooter isn't bad, to the side not so much, but that's any brake.
https://precisionarmament.com/hypertap-muzzle-brake/
Agreed. It's one of the most effective brakes I've used but with significantly less concussion than other top performers.
I’ve got a new Christensen Arms from my MPR you can have if you cover shipping. 5/8 24 thread I believe from a 6.5 PRC. Probably don’t want black though
Stainless Steel Side-Baffle Brake - Christensen Arms
Specifications: Stainless steel 1/2 x 28 for .223 and 5/8 x 24 for .30 and above Weight 4 oz. for 1/2 x28 and 3.2 oz. for 5/8 x 24 Includes crush washer for proper indexing Made to fit a .920 bull barrel diameter Available in Natural, Burnt Bronze and Black Nitride Also available in Titanium
christensenarms.com
I really like the Holland brakes, they didn’t change the accuracy of the rifle and don’t kick up dirt or blow back onto your scope glass. It sure tamed a lightweight 30-06 for me. Checkout this article the APA brakes rated really well too. The 419 rails I’ve seen are top notch so I bet their brakes are excellent too. https://precisionrifleblog.com/2015/07/25/muzzle-brakes-ability-to-stay-on-target/
I doubt you’ll need the adjustable gas block. They seem to be gassed conservatively. 6.5 a419 match on mine and the gun doesn’t move. I’d say an Apa gen 3 would be nice too for the ability to tune it.
Proof recommends JP to be headspaced correctly for their AR barrels. Shaw recs Alexander Arms for their 6 ARC. Specifically 0.136” bolt face depth. JP’s are 0.136 also.
Noveske also uses JP for some of their "odd" calibers.
I don't know anything about these guys, haven't used their stuff, but they were recommended on arfcom.
I have also used Maxim bolts with good results so far.
I have also used Maxim bolts with good results so far.
For bolts I have a Maxim & JP.
These weren't available yet, but are in stock now. I would try one if I buy another. S7 Tool steel & DLC coating.
https://www.srcarms.com/bolts/6.5-grendel-type-2-bolt
These weren't available yet, but are in stock now. I would try one if I buy another. S7 Tool steel & DLC coating.
https://www.srcarms.com/bolts/6.5-grendel-type-2-bolt
Yes. I doubt JP is making special JP marked 6.5G bolts for Noveske; they should be standard JP OEM.
I believe that’s a pretty respectable company. The fact that they bother to specify steel properties, coatings and 0.136 depth with some cautionary instructions says a something positive. Also a good price.
Interesting, I will have to check my Noveske 6.5G bolt later.. what am I looking for? What's the difference between "special" and "standard" JP bolts, or did you just mean the marking?
Is Leverevolution really the bees knees for 105gr compared to cfe223 before I order a jug?
I'm stocked up on Lever. Never tried CFE and not really itching too. I've never seen a post where CFE beet Lever for speed or temp stability.
I suppose if I couldn't find an accurate load with Lever I'd give CFE a try, just hasn't happened yet.
In my experience those two powders are very close to each other in the ARC.
Lever by a nose but very close . Either works well. 2100+ rounds in between two rifles. If you can find both buy Lever butttt you won't be hurt buying 223
I was under the impression that lever was pretty temp UNstable. Is that not the case? I've been using varget and benchmark for 90s and pressuring out, but some more speed would be cool. Ive heard lever will get you more fps without too much pressure but you've gotta be carefuk with temps.
Yes that's the case but all the temp stable powders are slower. So pick your poison, I pick the unstable and crank it up when cooler and back it down when hotter. I get around 2750 is out of a 22" BA barrel with 29.7gn Lever loaded with a 105 VLD Hunter @ 2.90 .070 off lands in 75-80 degree weather @ basically sea level. I may go out tomorrow and give 29.9gns a go and report back. Weather calls for 50+ degrees Sunday in Ellerbe NC
Relying on memory but I thought CFE223 was temp stable. Like to the extent of Varget. FPS is similar to Lever
The data I have is posted below.
I really haven't seen the temp instability many claim. I would qualify that with my experience is limited to small cases pushing heavier projectiles. These loads are efficient, high case fill, low SD loads.
I only use JP (.223) bolts now combined with using Phil Wood Tenacious Oil on the back of the locking lugs. Since using the Phil Wood the finish stayed on my new bolt and it seems to have stopped wearing off on others that were previously lubed with a quality gun oil. After talking to Conrad White of Compass Lake de-burring/polishing the inside of the barrel extension also significantly helps bolt lug life regardless of the bolt maker. Two smooth hardened surfaces sliding against each other with proper lubrication will have a happy long life. While your polishing the feed ramps you might as well. All these little things add up when running a higher pressure cartridge that could be run too hot easily when re-loading. Unlike a bolt action you don’t have the luxury of feeling that hard to lift bolt your strictly reading the brass looking for high pressure signs. JP bolts are a bit more expensive but if taken care can be used on multiple barrels and they do the little details so well in their bolts. Great article on AR lubing and other things from the pioneer of the 6mm AR. The bolt lube suggestion worked for me.
That company is an offshoot from the owner of the 6.5grendel forum. It is a very well made bolt with attention to detail such as the extractor has proper geometry and is not nitrided, which is the proper way. The only "finishing" it needs is breaking the sharp edge in the extractor channel to reduce brass shaving like most AR bolts.
I wish I could say the same about the 6.5 Grendel barrels but they made compromises to shoot the crap Wolf steel case better at the expense of "good" ammo.
I have had very similar experience with Lever under the 109 Berger. Not temp stable but by recording good data, predictable changes. From my memory, more stable (less change) from around 50F to low 70s, a bit more above and below that. I can work with that.
LOL. No, CFE223 is definitely NOT a temp stable powder. It’s as bad or worse than Lever in that regard.
Well my memory is shit. Sorry. I wonder why the hell I bought 6 pounds of it a couple years ago?
Well my memory is shit. Sorry. I wonder why the hell I bought 6 pounds of it a couple years ago?
When powders were hard to find? It's still a decent option for a whole bunch of different AR15 cartridges and 308 Win, even if it's not "temperature stable"
*Temperature stability is not a yes or no thing. It's a gradual slope, with some powders being more temp stable than others. Most ball powders are not very temp stable, with the exception of very new stuff like Staball 6.5 (which is a poor choice in the 6 ARC anyway).
For sure, been waiting for that to come out for a while, the rumors started shortly after 6.5 STB came out.
I had worked up some loads for my 18" hunting ARC, but hadn't been able to Chrono them yet, finally dug up the F1 Chrono and ran a few over.
95gr SST, 29.5gr LVR, 2.1" - 2,676 fps, 2,680 fps
100gr TGK, 29.3gr LVR, 2.27" - 2,676 fps, 2,665 fps
108gr ELD, 29.3gr LVR, 2.245" - 2,650 fps, 2,634 fps
Also worked on a load for 90gr TGKs, and chrono'd this spread:
90gr TGK, LVR, 2.265
30.4gr - 2,802 fps
30.7gr - 2,834 fps
31gr - 2,874 fps
31.3gr - 2,935 fps
That's not too far off of my 21" velocities, I'll probably take either the 108gr ELD or 100gr TGK loads out to hunt with since they shoot pretty close to each other and are carrying respectable velocity
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