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Thread: 30RAR vs 30 HRT

  1. #1
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    Default 30RAR vs 30 HRT

    30RAR vs 30 HRT how do these compare? I want a 30 HRT upper! I know Harrison was talking about doing a 30 HRT, but gave due to the lack of a reamers from PTG. I also see the 30RAR being kicked around and was wondering how these two compare.

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    There is apx 150-200 fps difference in favor of the RAR.
    The RAR is a single stack mag or really feeds from the center, 30 HRT same as the 6.8.
    RAR uses a special bolt and extension, HRT same as 6.8.

    If it was me I will still keep the bullet weight down to around 130gr to keep velocity up so the bullets expand in either cartridge.
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    The RAR is faster but too many non standard parts for me. I went with the HRT. Mine is throwing 110 gr. bullets at 2594.4 fps out of a 16 inch barrel so another 400 fps (out of a 22 inch barrel) to me is not outweighed by the lack of mags, capacity, and standard parts. Throw in a good ARP Super Bolt and you can drive the HRT as hard as you want, likely equaling or nearly equaling the RAR in equal barrel lengths and still get to use standard 6.8 bolts and mags.

    You can always buy any .300 BO barrel you want and have it rechambered. Thomas at Paladin Machine Shop Service rechambered my barrel to 30 HRT and it is doing great. Mine is a 1:12 twist which is way too slow for subsonic shooting of heavies but you can get a BO barrel in just about any twist/length you want if subsonic loads trip your trigger, and a 1:8 twist will shoot the lightweights just fine too. I have no intention of going slow, that's what the Spectre is all about, so I went with the 1:12 because I will very likely shoot nothing heavier than 125s and most likely nothing but the 110 gr. bullets will go down the barrel.
    Last edited by Big Bore; 11-25-2012 at 12:59 AM.
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    Thanks for the info guys! I am still thinking about the 308 with ARP 16" or 18", but wanted to use ar15 receivers vs the heavy and $$$ ar10's and the HRT and RAR fit. I dont plan on any sub sonic shooting. Just pigs and deer.

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    Quote Originally Posted by Big Bore View Post
    The RAR is faster but too many non standard parts for me. I went with the HRT. Mine is throwing 110 gr. bullets at 2594.4 fps out of a 16 inch barrel so another 400 fps (out of a 22 inch barrel) to me is not outweighed by the lack of mags, capacity, and standard parts. Throw in a good ARP Super Bolt and you can drive the HRT as hard as you want, likely equaling or nearly equaling the RAR in equal barrel lengths and still get to use standard 6.8 bolts and mags.

    You can always buy any .300 BO barrel you want and have it rechambered. Thomas at Paladin Machine Shop Service rechambered my barrel to 30 HRT and it is doing great. Mine is a 1:12 twist which is way too slow for subsonic shooting of heavies but you can get a BO barrel in just about any twist/length you want if subsonic loads trip your trigger, and a 1:8 twist will shoot the lightweights just fine too. I have no intention of going slow, that's what the Spectre is all about, so I went with the 1:12 because I will very likely shoot nothing heavier than 125s and most likely nothing but the 110 gr. bullets will go down the barrel.
    What is the freebore length on the HRT reamer he has? A 30 Herrett reamer freebore is too long but not sure by how much since I can't even get a drawing from PTG to modify it for AR use.
    SIX5 -6.5mm on a 6.8 case-vel of the 6.8, BCs of the 6.5
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    The 6.8 is the #1 choice for hunting deer and hogs with an AR15

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    Quote Originally Posted by constructor View Post
    What is the freebore length on the HRT reamer he has? A 30 Herrett reamer freebore is too long but not sure by how much since I can't even get a drawing from PTG to modify it for AR use.
    Not sure H. I never thought to ask. I will try and take some measurements tomorrow and get back with you. If I forget, and that is likely at my age, drop me a PM or email to remind me. I do know that it is long enough to use a 240 SMK and not exceed 2.260 inch.

    OK, couldn't wait and measured it. 1.942 to lands. With a case length of 1.610 maximum then you have a throat/freebore of .332. Since so much of the bullet has to be in the case to fit in the limits of the AR mag the throat is not long at all.
    Last edited by Big Bore; 11-26-2012 at 12:13 AM.
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    Quote Originally Posted by constructor View Post
    What is the freebore length on the HRT reamer he has? A 30 Herrett reamer freebore is too long but not sure by how much since I can't even get a drawing from PTG to modify it for AR use.
    H, can you get the dimensions off Marty's website?
    I don't have a bookmark on my iPad for it.

    Oh, IIRC, I think you have to trim the 6.8 case .044.?
    Last edited by WVHunter1s1k; 11-26-2012 at 12:32 AM.
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    You have to do more than just trim the case. It needs to be either neck expanded to .30 caliber via a tapered expander and then sized in a .30 Herrett sizing die or if you are using a sizing die with a tapered expander, like Hornady, then you can just run the 6.8 case into the sizing die and do it in one step. The .30 HRT is extremely simple to form. Then you just trim to 1.605 inch. 1.610 inch is the maximum case length and as normal, you should trim to between .005 and .010 inch shorter than that. Marty has settled on .005 shorter for the .30 HRT. While it has been reported that Silver State Armory brass leaves a doughnut in the neck I have found that with current cases that is no longer true. New SSA 6.8 SPC brass left no doughnut what so ever and the necks did not need reaming in the least.
    Ergo, actual chamber dimensions are the exact same as the .30 Herrett except for the lack of a rim and the throat length. AR15barrels.com had the chamber dimensions for the .30 HRT sans throat but they are no longer there; at least I could not find them just now. I do not believe Marty has them on his site.
    Last edited by Big Bore; 11-27-2012 at 12:17 AM.
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