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12.5" AR Update, new configuration, w/pictures

JasonMPDJasonMPD Senior MemberPosts: 6,583 Senior Member
I got curious. This usually sends me down rabbit holes with no purpose or direction. But I took the Trijicon MRO off the 12.5 and put on my Vortex Viper PST 1-4x.

With an optic (albeit a 1-4x), what can the rifle potentially do? 

Right away I had to put aside 55gr ammo and get some heavy class ammo. Hornady Black 75gr HPBT shot well in my 16" guns, so I went to buy some.  All out.  Crap.

What Academy did have was Frontier branded ammo, 5.56 NATO spec, loaded with 75gr Hornady HPBT bullets.  I'm interested...  the Hornady Black "equivalent" is 223 REM spec.  Frontier is $9.99 a box and Hornady Black is $14.99 a box.  Very interested...

Let's shoot.

First, let me say that a 12.5" barrel does worlds better for velocity than a 10.5" barrel.  A LOT. Similar ammo in 10.5 inch barrels I've measured at about 2400 FPS, plus or minus.  This Frontier ammo exits at an average of 2609 FPS.  That's amazing and is about 200 fps faster thanna 10.5 barrel.

What's the numbers on this $10.00 "match ammo"? 2609 FPS and a 9.0 SD.  Wow.  And that's a 15 shot string.  What's that equate to at 200 yards? This.



(Note: orange dot is not POA. I pasted it there so the phone app had the 1" reference needed.)

Needless to say I have my new ammo for this gun and its inexpensive.  I'm working on replicating it at the reloading bench. I'm fairly certain the powder they use is H335.  Reloading data available suggests that too.  223 REM data "max" is 23gr in Hodgdon's guide and the case had 24gr in it. 

Is 1gr the difference between 223 and 5.56 specs? Maybe. I'll find out. It could also be MAYBE Hodgdon CFE223.  Looks sorta like that one too, but edges out looking more like H335.  Both have similar max data for 75gr bullets.  So it begins.

Here's some pics of the rifle in it's new permanent configuration.  It's a CQC/medium range (400-600 yard) rifle now.  2600fps with 75gr ammo makes it a very, very capable platform.


“There are three kinds of men. The one that learns by reading. The few who learn by observation. The rest of them have to pee on the electric fence for themselves.” – Will Rogers

Replies

  • Diver43Diver43 Senior Member Between Ft Lauderdale and MiamiPosts: 12,556 Senior Member
    Looks like you found a good combination.
    Logistics cannot win a war, but its absence or inadequacy can cause defeat. FM100-5
  • ZeeZee Senior Member Posts: 28,060 Senior Member
    Looks good. 
    "To Hell with efficiency, it's performance we want!" - Elmer Keith
  • BAMAAKBAMAAK Senior Member Posts: 4,484 Senior Member
    Nice.  What brand barrel you using?  I like H335,   currently trying to see how low I can go with it.  Down to 18.5 grains now and still have a bunch of adjustment in the gas block.  I think I can get down to 17.5 or so and still be reliable.
    "He only earns his freedom and his life Who takes them every day by storm."

    -- Johann Wolfgang von Goethe, German writer and politician
  • Ernie BishopErnie Bishop Senior Member WyomingPosts: 8,566 Senior Member
    I like it
    Ernie

    "The Un-Tactical"
  • JasonMPDJasonMPD Senior Member Posts: 6,583 Senior Member
    BAMAAK said:
    Nice.  What brand barrel you using?  I like H335,   currently trying to see how low I can go with it.  Down to 18.5 grains now and still have a bunch of adjustment in the gas block.  I think I can get down to 17.5 or so and still be reliable.
    Centurion Arms barrel.
    “There are three kinds of men. The one that learns by reading. The few who learn by observation. The rest of them have to pee on the electric fence for themselves.” – Will Rogers
  • JasonMPDJasonMPD Senior Member Posts: 6,583 Senior Member
    I got the suppressor last Thursday, but work has been hectic.  Here are a couple stylized photos.



    In the direct thread configuration it adds about 4.5" overall length.  The QD configuration is about 5.5".  The QD adapter and muzzle device weigh as much as the direct thread configured suppressor.  The DT configuration probably weighs about a pound.

    I should have some test results soon.
    “There are three kinds of men. The one that learns by reading. The few who learn by observation. The rest of them have to pee on the electric fence for themselves.” – Will Rogers
  • GunNutGunNut Posts: 7,642 Senior Member
    Damn!  Liking that gun a lot!
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