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Thread: Ditching 5.56 discussion

  1. #41
    Quote Originally Posted by Mike C View Post
    With Barnes 110ís the fastest I saw from my 9Ē Ballistic Advantage barrel with max of Lilí Gun was right around 2130-2145. I may have seen really close to 2150 but never much more than that with mine. I donít recall exactly but it was somewhere right around there. Factory stuff was spot on at 2150 some times a little more or less. I started seeing flattening and occasionally a blown primer at max loads so I stopped where I was at. I wouldnít try pushing it harder.
    Max loads with the 120gr TSX with h110 is getting me around 2040 fps out of a 9.5Ē barrel. No problems with primers so maybe there is little left.

  2. #42
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    Quote Originally Posted by LittleLebowski View Post
    Jeez, talk about a formatting and quote ninja . Iíll try to respond to your stuff in red, forgive me if I canít keep.


    • Iím well aware that all rounds have backpressure, but the difference between the two is noticeable. As in I donít notice it at allwith my suppressed .300BO guns, but itís enough of a problem with my suppressed 5.56 guns that I have to buy AR Gas Vents, fuck with buffer weights, buy adjustable gas blocks, and RTV the charging handles.
      I have not done any of these things. It sounds like gas ports are more of an issue than ammunition/caliber, in your case. My DD 300BLK was pretty well gassed, and with subsonics, I got a ton of filth in the receiver due to the type of powder used (Remington 220gr), or similar backpressure to a 5.56, which in my case has always been minimal, using Supersonic (Blacktip 110gr)
    • My AR pistols are lighter than 16Ē rifles.
      AR pistols come in whatever caliber though...
    • Reloading for the .300BO is very rewarding, especially when I can work up a load and test it quietly with about twenty steps out my back door. This goes back to me not having a use for 300BLK subs. You do. Again, tool is being fitted to mission/environment, as I test supersonic 10 feet from my garage to no ill effect.
    • As a father of two school age children, my time is very valuable. If I can reload .300BO without trimming, I save time. Furthermore, being able to use cast bullets saves me a LOT of money. Maybe I suck as a reloader, oh well. My dad never trimmed 5.56 brass and all was well. Of course, he only reloaded it once or twice per case.
    • The advantages of a 3-lug are no indexing the muzzle device, cheap(er) muzzle devices, no backing off of the muzzle device, extremely easy mount and unmount, the mount rarely if ever needs cleaning, and hardly ever get stuck. That's cool, I only use Surefire stuff, but I'll look into that design.

    I try with the formatting.

  3. #43
    Quote Originally Posted by ldunnmobile View Post
    Really surprised there isnít more 6.8 love. Out of a 16Ē gun I can shoot 120gr Hornady SST with near identical trajectory to 500 yards as my 5.56 77OTM but with significantly more ďpunchĒ. Also 90gr Fusions are awesome out of it for a high velocity rounds that is excellent on game. Plus they are easy to run/not finicky at all.
    What kind of velocity are you getting on those 120s? Is it a factory load? I'm plugging in Hornady factory data and it doesn't look anywhere close to 5.56 77gr from a 16" barrel.

  4. #44
    Quote Originally Posted by littlejerry View Post
    What kind of velocity are you getting on those 120s? Is it a factory load? I'm plugging in Hornady factory data and it doesn't look anywhere close to 5.56 77gr from a 16" barrel.
    Iím use an ARP chamber in the 6.8 and it eeks a bit more velocity. I figure 2500 FPS from checking dope yesterday. I was hitting higher than expected at 400 and adjusted. The Hornady factory load is pretty mild. If I get the itch to hand load should easily attain 2560-2600.

    Only .1 mil windage behind 77gr SMK at 500.

    Left: 6.8 120sst at 2500

    Right: 5.56 77 SMK 2650

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  5. #45
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    I went with 6.8 SPC II for my "large" AR round. A 110-grain bullet at 2300-2400 fps is more than sufficient on Alabama deer and the distances I need (maximum of 150 yards and often less then fifty yards), and I can use my current lowers. I had White Oak Armament build me the upper and installed it on a BCM lower. I added a Leupold M8-6X scope. I have a Larue trigger for it but the lower has the stock BCM trigger still installed.

    A shooting buddy went with .300 AAC (BLK), and he likes it for hunting as well if he runs supersonic loads.

  6. #46
    Site Supporter DocGKR's Avatar
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    Really surprised there isnít more 6.8 love.
    6.8 mm is my favorite hunting cartridge in an AR15 out to 300 yds or so.
    Facts matter...Feelings Can Lie

  7. #47
    Quote Originally Posted by ldunnmobile View Post
    Iím use an ARP chamber in the 6.8 and it eeks a bit more velocity. I figure 2500 FPS from checking dope yesterday. I was hitting higher than expected at 400 and adjusted. The Hornady factory load is pretty mild. If I get the itch to hand load should easily attain 2560-2600.

    Only .1 mil windage behind 77gr SMK at 500.

    Left: 6.8 120sst at 2500

    Right: 5.56 77 SMK 2650

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    Ah. That makes a little more sense now.

    I also chrono 5.56 77gr at 2750 in my rifle which adds a bit more difference. I see ~.3 mil difference of windage (not too bad) and ~1 mil of elevation at 500 vs the factory(2450 fps) Hornady specs.

  8. #48
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    Quote Originally Posted by DocGKR View Post
    6.8 mm is my favorite hunting cartridge in an AR15 out to 300 yds or so.
    Excuse the threat drift, but I'm curious how the 6.8 compares to the 6.5 Grendel for medium sized game. I'm considering an "alternative" AR caliber for deer in CA, and was leaning towards the 6.5 G. Cans are out of the question here, so 300 BO is not really a contender.

    (P.S.: my question is for the P-F braintrust, not just Doc.)
    Last edited by Mark D; 05-05-2019 at 09:49 PM.

  9. #49
    Quote Originally Posted by Mark D View Post
    Excuse the threat drift, but I'm curious how the 6.8 compares to the 6.5 Grendel for medium sized game. I'm considering an "alternative" AR caliber for deer in CA, and was leaning towards the 6.5 G. Cans are out of the question here, so 300 BO is not really a contender.

    (P.S.: my question is for the P-F braintrust, not just Doc.)
    From a pure ballistics view 6.5G is better. Many reports of Grendel feeding issues and bolts breaking scared me off vs the no muss no fuss 6.8. One day the industry may get it ironed out. I'm sure some 6.5G users probably are getting close by now.

    I'd like to see something like the Tac 6 go mainstream. 6.8 SPC case with the shoulder bumped back to accommodate the 100gr+ class of 6mm bullets.

  10. #50
    King of Craft Clusterfrack's Avatar
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    Ditching 5.56 discussion

    My Alexander Arms 6.5 Grendel 16Ē lightweight upper has been flawless. For a $600 upper, Iím blown away by how accurate it is out to 900yds.
    Last edited by Clusterfrack; 05-05-2019 at 10:58 PM.
    "BJJ is sort of like nonconsensual yoga"
    "You donít really graduate from certain problems or certain thingsÖ like you always have to work on trigger control and pulling the trigger straight. " --Ben Stoeger 1/24/2018

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