jtallen83 Posted February 27, 2017 Report Share Posted February 27, 2017 Just noticed these 18 inch rifle length gas barrels for AR-10's with a 1:8 twist. Anyone heard of running this twist in a 308 before? Purpose? https://armalite.com/shop/ar-10-308-18-target-barrel-black/ They also have 1:10 twist on an 18 inch rifle length gas barrel, I may just have to grab one, with well over 3,000 rounds on my AR-10 barrel and the increasing scarcity of manufacturers making barrels for it it can't hurt to have another ready to go. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted February 27, 2017 Report Share Posted February 27, 2017 (edited) Missprint ? Edited February 27, 2017 by survivalshop Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted February 27, 2017 Author Report Share Posted February 27, 2017 7 hours ago, survivalshop said: Missprint ? Thought about that but noticed they have the same two options on their 13.5 inch target barrel. I hope to get a response from them, the old Armalite was always forthcoming with information, the new owners hide behind the export ban when not wanting to share info. Quote Link to comment Share on other sites More sharing options...
planeflyer21 Posted February 27, 2017 Report Share Posted February 27, 2017 The 1:8 twist on .308 bored barrels is for the new super heavy long-distance rounds, with the projectiles being 295gr with the tungsten core and the military-only depleted uranium coming in at 365gr. Muzzle velocity is low for both, below 2000fps, but both still retain over 1600fps past 1400 yards. The ability to punch through light armor at 700 yards is pretty impressive if you ask me! Interesting that these are being sold to the general public. I was under the impression they were only being sold for remotely operated platforms on the new Chevrolet Knight Rider and Bell Helicopters Airwolf 2020 project. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted February 27, 2017 Report Share Posted February 27, 2017 That would make some sense , but that weight Bullet would have the trajectory of a Bowling Ball & I don't buy the Armor penetration with the Tungsten core , the Depleted Uranium , maybe , because it creates its own energy at point of impact . I thought or read somewhere that it too has to be at a hyper speed to accomplish this , but I really don't know anything about this Barrel or ammo , got a link ? Quote Link to comment Share on other sites More sharing options...
mineralman55 Posted February 27, 2017 Report Share Posted February 27, 2017 49 minutes ago, survivalshop said: ... the Depleted Uranium , maybe , because it creates its own energy at point of impact . I'm not sure what you mean by that. A DU round can't "create" energy any more than any other projectile. A DU round, like any other projectile upon impact, will convert some of its kinetic energy into heat energy. With a very hard, very high speed projectile like a DU round, it will either penetrate and/or convert to a tremendous amount of heat capable of melting the object it is impacting. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted February 27, 2017 Report Share Posted February 27, 2017 9 minutes ago, mineralman55 said: I'm not sure what you mean by that. A DU round can't "create" energy any more than any other projectile. A DU round, like any other projectile upon impact, will convert some of its kinetic energy into heat energy. With a very hard, very high speed projectile like a DU round, it will either penetrate and/or convert to a tremendous amount of heat capable of melting the object it is impacting. Not to be too argumentative , but isn't that what I said . Velocity , impact/ kinetic energy , creating heat , which is enhanced because of the material used ( Deplete Uranium ) Once that crap is heated to a point , its like Magnesium ( may be a poor example , but I think you get the point ) Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted February 27, 2017 Report Share Posted February 27, 2017 I've read a few interviews with Todd Hodnett, stating that he has often shot well beyond 1K with a 1:7 or 1:8 twist in .308. Yes, with heavier bullets. Communicating with Bryan Litz, he also advocated for a faster twist at long range with heavier projectiles when trying to find the best B.C. I also think Remington used to sell a ~18" 700 bolt action with a 1:7.5 twist from the factory, or something similar. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted February 27, 2017 Author Report Share Posted February 27, 2017 How heavy a bullet could I actually use in my AR-10 though? The 175's are pushing the COL the way it is. If I knew I could use something 220 or higher I'd grab one of those 18 inch rifle gas barrels for the money. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted February 27, 2017 Author Report Share Posted February 27, 2017 18 hours ago, survivalshop said: Missprint ? Nailed it, both examples are a misprint. They are going to correct it soon, I should have ordered and then asked for a discount when I didn't get what I ordered instead of asking questions....... Quote Link to comment Share on other sites More sharing options...
MikedaddyH Posted February 27, 2017 Report Share Posted February 27, 2017 Too bad ! I was looking forward to getting information on heavy 30 cal projectiles. Like the Sierra 250gr or the elusive Barnes "O" 250gr bullet. Those are supposed to shoot through a herd of caribou and land on the tundra. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted March 3, 2017 Report Share Posted March 3, 2017 On 2/27/2017 at 9:58 AM, jtallen83 said: How heavy a bullet could I actually use in my AR-10 though? The 175's are pushing the COL the way it is. If I knew I could use something 220 or higher I'd grab one of those 18 inch rifle gas barrels for the money. Hornady 10 load manual changes all that. Loading 220s at 2.800 C.O.L. now. .308 Win travelling at well beyond subsonic, but helpful in suppressed use. Hornady 9 manual only listed up to 195 BTHPs loaded to 2.800 C.O.L. This new stuff changes everything. And 1:10 won't cut it as well as the (even) faster twists. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted March 3, 2017 Report Share Posted March 3, 2017 Quote Link to comment Share on other sites More sharing options...
98Z5V Posted March 3, 2017 Report Share Posted March 3, 2017 Here's the info on the .308 Win 212s, but the C.O.L. listed is 3.000". Not gonna work in a mag-fed .308AR. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted March 3, 2017 Report Share Posted March 3, 2017 I'm shocked at the powders listed - we're still using Varget and RL-15 to push these fat bastards! I'M. IN. Quote Link to comment Share on other sites More sharing options...
MikedaddyH Posted March 3, 2017 Report Share Posted March 3, 2017 I made a batch of Speer grand slam 200gr 308win ammo at 2.810" . its supposed to be good with 1-10" barrels. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted November 6, 2017 Author Report Share Posted November 6, 2017 I caught a podcast today with an interview of Bryan Litz of Applied Ballistics and Berger Bullets. After hearing this and seeing that the new ArmaLite site still lists the 13.5 inch barrel at 1:8 twist I don't think it is a typo. Bryan stated that because of the loss in velocity of the shorter barrel a faster twist is needed to stabilize projectiles when they go transonic. It confused me a bit because transonic is transonic, might happen at a different range but the same thing happens? He had a lot of ballistic mumbo jumbo about the physics of it but I would tend to just accept his word. He did say that there would be little to no difference before the bullet hits transonic. https://www.armalite.com/product/ar10-308-13-5-target-barrel/ http://www.precisionriflemedia.com/podcast/2016/4/28/prm-005-bryan-litz Quote Link to comment Share on other sites More sharing options...
98Z5V Posted November 6, 2017 Report Share Posted November 6, 2017 It's a typo - and I've contacted Armalite about it. They don't seem to care. They copied most of the description for these barrels right from the 5.56 version/listings (which, those two 3-Gun barrels in 5.56 are 1:8 twist). One day, they'll change it to 1:10" like it really is. Or, they won't. They didn't seem to care that I pointed it out to them. I have the 13.5" .308 Win barrel, and it's a 1:10" twist. Shoots like a champ, too. Rob was the first one to fire it up, and it does run. MAN, does it run!... Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted November 7, 2017 Author Report Share Posted November 7, 2017 18 minutes ago, 98Z5V said: It's a typo - and I've contacted Armalite about it. They don't seem to care. Wonder why they fixed one typo and not the other? Either way once the preeminent Ballistician of our day starts recommending a 1:8 for short barrel 308's you can bet there will be some on the market soon. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted November 7, 2017 Report Share Posted November 7, 2017 It's imprinted on the barrel. If you look at the other detailed pics in the product listing, they might still have the pic that shows the barrel markings - I looked at that before I bought the barrel, but was going to buy it anyway if it was 1:8". It's marked "7.62AM SS 1:10." Here's the beast" Quote Link to comment Share on other sites More sharing options...
StainTrain Posted November 7, 2017 Report Share Posted November 7, 2017 I run a 1:8 in a bolt gun .308 and love it. I am sorry I'm late to the party. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted November 7, 2017 Author Report Share Posted November 7, 2017 2 minutes ago, StainTrain said: I run a 1:8 in a bolt gun .308 and love it. I am sorry I'm late to the party. Tell us more, barrel length, best performing bullets, worth trying in a gas gun? Quote Link to comment Share on other sites More sharing options...
StainTrain Posted November 7, 2017 Report Share Posted November 7, 2017 16 inch medium Palma. It does great with 168smk, 178 eldm, 175smk, 175 Berger, 185OTM (but it is difficult to get the velocity up with 185s) I haven't tried 155s. I think you will like it. it performs well Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted November 7, 2017 Author Report Share Posted November 7, 2017 Sounds like plenty of good bullet choices for a gas gun then. I have been mulling over a 12.5 inch pistol build to replace my P716, it might just be the ticket for that. Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted November 7, 2017 Report Share Posted November 7, 2017 That 13.5” is a bad bitch! I blasted the hell out of it. Im sold on it. I WILL HAVE ONE. Just not sure if I want to brake it or pig it. A pig sticking out of a 15” Apex tube would be mighty awesome. Quote Link to comment Share on other sites More sharing options...
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