AR15 in 6.5 Creedmoor?

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  • ToolAA

    Ultimate Member
    MDS Supporter
    Jun 17, 2016
    10,499
    God's Country
    18” for 123gr ELD-M should still be 1000yd capable so long as it isn’t a humid day at sea level. It’s a difference of like 40-50fps. Nothing to sneeze at and useful/needed if you are shooting long range. Even at 600yds it makes a big difference. If it is a hunting rifle that maybe a couple of times you’ll take it to a range with 500 or 600yd targets, go 18”. Handier more than the reduced weight.


    Are you sure? I thought the higher the humidity the less dense the air. Which means less drop. So higher humidity at any altitude would equate to less drag.
     

    ted76

    Ultimate Member
    MDS Supporter
    Jan 20, 2013
    3,151
    Frederick
    Humid air is denser than dry air, it has more water in the air, and that slows down objects traveling through it.
     

    erwos

    The Hebrew Hammer
    MDS Supporter
    Mar 25, 2009
    13,866
    Rockville, MD
    6.5 Grendel is no joke. I've got an AR and a bolt gun in it, and it's like 5.56x45 recoil with 7.62x51 performance with 27rd mags. While .224 Valkyrie has some minor advantages in distance shooting, the retained energy of 6.5 Grendel just dominates it to the point that it's hard to see that minor distance advantages as worthwhile. You also get cheap steel-cased ammo to fall back on for volume shooting, which is also pretty great. As I like to say, 6.5 Grendel isn't the best at everything, it's just almost the best at everything and has no substantial weaknesses.

    As for 6.5 Creedmoor, excellent cartridge if you're trying to punch out past 700 yds regularly. If that is genuinely a requirement for you, you're on an AR-10 platform.
     

    ToolAA

    Ultimate Member
    MDS Supporter
    Jun 17, 2016
    10,499
    God's Country
    Humid air is denser than dry air, it has more water in the air, and that slows down objects traveling through it.



    But water vapor makes air less dense than dry air. Compare ballistic solutions with 0% RH vs 100% RH with all other variables the same. You’ll see that at 100% RH the projectile is traveling about .3% faster and drops less at 1000yds.

    It’s sort of counterintuitive because humid air does feel heaver. I think it was Ed Shell who explained it. Water vapor contains hydrogen which is lighter than oxygen and nitrogen.
     

    woodline

    Ultimate Member
    MDS Supporter
    Jan 8, 2017
    1,947
    The problem with 6.5 Grendel is that every time I start speccing out a build, I end up wanting three separate builds: a 12" upper, a light and handy 18" upper, and a long range 24" upper. .224 Valkyrie, .22 nosler, etc don't really hold my attention like 6.5 Grendel does.

    6.5 creedmoor is pretty dang cool as well. That one's easier to figure out as I'd enjoy putting together a long range upper chambered in that for my large frame AR.
     

    Bart_man

    Clinging to gun&religion
    Jan 8, 2011
    2,310
    Hazzard County
    So get an 18”and 24” upper you are good to go


    Sent from my iPhone using Tapatalk


    Like this?

    18" barrel .308 upper on the gun.
    24" barrel 6.5cr upper below it.

    Proof Research barrels
    Lancer systems hand-guards.
    Syrac ordinance Adjustable gas blocks
    Witt Machine MRE muzzle breaks
    And
    only ONE BCG JP Low Mass

    10918921_10203635297824686_7404634572302480976_o.jpg
     

    bilbravo

    Active Member
    Apr 30, 2013
    417
    Baltimore (District 46)
    Sorry to go a bit off topic here, but I have a stripped lower and was wanting to build a rifle (not another pistol). I was thinking 9mm (because it's cheap) or something more exotic. Is the 6.5 Grendel build likely to be better with a 20" barrel? It sounds interesting.

    Also I assume as long as an AR-15 isn't built with .223/5.56 the barrel profile and whatnot doesn't matter so long as it meets overall length, etc? Basically the only "banned ar15s" are .223/5.56 non-HBAR?
     

    erwos

    The Hebrew Hammer
    MDS Supporter
    Mar 25, 2009
    13,866
    Rockville, MD
    Sorry to go a bit off topic here, but I have a stripped lower and was wanting to build a rifle (not another pistol). I was thinking 9mm (because it's cheap) or something more exotic. Is the 6.5 Grendel build likely to be better with a 20" barrel? It sounds interesting.
    Define "better". Shoot a thousand yards better? Yes. Assaulter-style shooting at 0-300? No.

    I covered both bases by going with an AR-6.5G SBR and a Ruger American. If I wanted to do both simultaneously, I'd probably choose an 18" semi-auto gun to split the difference.

    One other thought: if getting good performance out of Wolf ammo is a necessity, you should go with an AA barrel. Other barrels don't always seem to perform very well with it. That said, my RAR did shoot better than I expected with it (and, frankly, it vastly outperformed some Russian 308 I was shooting on a different rifle).

    Also I assume as long as an AR-15 isn't built with .223/5.56 the barrel profile and whatnot doesn't matter so long as it meets overall length, etc? Basically the only "banned ar15s" are .223/5.56 non-HBAR?
    That is the current line of thought, yes.
     

    DavidA

    The Master of Disaster
    Dec 6, 2013
    371
    Annapolis
    For me at 6’ 5 1/2”and 290 lbs athletic build I went with a 20”as weight is not that significant factor for me . For the extra 12 once’s I don’t care. For most a 18” splits the middle and you are good 0-600 with ease and is good out to 1,000 yds with a 123 gr Scenar at 2,500 FPS.

    I did order a 24” barrel though just for another 175-180 FPS which extends range by 150 yds or so. That’s just for fun .

    The 18” barrel does a great job. Using the 123 gr Scenar at 2,500 FPS at 300 yds 2,094 FPS, 1,198 ft lbs. 600 yds 1,729 FPS , 817 ft lbs.

    Such a great round for the AR 15 platform. For true defensive work a 100 gr or 107 gr SMK will do the trick as well. an 18” will develop approximately 2,690 FPS so at 300 yds 2,210 FPS with 1,161 ft lbs and at 600 yds, 1,777 FPS and 752 ft lbs.

    These are all at sea level, but I just love the round, if you can’t tell. It just does everything so well.



    Sent from my iPhone using Tapatalk
     

    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    Define "better". Shoot a thousand yards better? Yes. Assaulter-style shooting at 0-300? No.

    I covered both bases by going with an AR-6.5G SBR and a Ruger American. If I wanted to do both simultaneously, I'd probably choose an 18" semi-auto gun to split the difference.

    One other thought: if getting good performance out of Wolf ammo is a necessity, you should go with an AA barrel. Other barrels don't always seem to perform very well with it. That said, my RAR did shoot better than I expected with it (and, frankly, it vastly outperformed some Russian 308 I was shooting on a different rifle).


    That is the current line of thought, yes.

    That could be on the AA barrel. Not sure what it is about my build, but I have worse accuracy with Wolf steel in my grendel build than any other gun I own with any other ammo. About 5-6MOA. It punches 1MOA with Hornady black casually and turns in closer to .75MOA with federal fusion. I haven’t tried anything else in it so far. I have SST and I am planning to start loading for it (actually reloading period) soon. I’ve read a lot of people getting 2.5-3MOA with it. Usually Wolf treats me well in my other guns.

    Hell, my SKS loves that crap. It runs about 2.5MOA with most stuff and iron sights. I literally can’t explain it, but Wolf military classic in my SKS regularly turns in 1.25MOA with irons. POI will shift a little after about 10 rounds and stabilizes by 20 at about an inch and a half lower at 100yds. Keeps churning in 1.25MOA though.
     

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