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Built an AR pistol.

Discussion in 'The Workbench: Builds And Modifications' started by tcecil88, Jul 27, 2018.

  1. tcecil88

    tcecil88 .30-06

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    1,181
    Lol. I like the honest answer.
    I have been looking at the Magpul bipods. They are nice and light. I have a few different bipods, a couple Harris, a Blackhawk 6-9" which is good for the range to sight in a .22, a UTG HD Recon 360, a UTG HD Recon Flex 2 piece M-Lok, and a UTG Super Duty, which is a little tank of a bipod. The UTG's are built heavy, but they are slow to deploy, so they don't usually stay on a rifle.
    meanstreak and John A. like this.
  2. tcecil88

    tcecil88 .30-06

    Messages:
    1,181
    Well, like any good AR15 guy, I had some parts laying around and eventually they built themselves into another pistol.
    Radical Firearms upper with a PSA Premium FA BCG, KAK 4.75" barrel and micro gas tube, Ergo adjustable gas block with a Midwest Blast Can and UTG Pro 7" rail. The Blast Can sticks out about 3/8's inch. Iron sights, Pic rail sections, barricade rest and Keymod covers are all UTG Super Slim. Pic rail covers, grip, trigger guard, and mag release are Magpul. The lower is Anderson, the trigger is Mil-spec (for now) with KNS pins. The controls are a Luth-AR ambi- safety, Troy ambi mag release, Geissele Maritime bolt catch and a CBC Industries charging handle. I think CBC means Chinese Blueprinted Copy, so we'll see how well it holds up.The brace is the SB Tactical SBA3 with an Armaspec SRS-H2 buffer system. The red dot is a Holosun HS515BU red dot sight w/ Killflash and a Vortex Optics 2032 battery holder.
    I built this one more for the range than anything else. I thought about building it as a .300, but decided on 5.56 as I have enough calibers for now. It is a little over 3 inches shorter than my other pistol. I have a 2" shorter KAK Flash can and a UTG Pro 5" Keymod rail on the way, so I could go 2 inches shorter yet and may still do it. I have not fired it yet, so the first range trip should be interesting. Deplorable P 1.0 RS.jpg Deplorable P 1.0 LS.jpg
    Last edited: Jun 21, 2019
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  3. John A.

    John A. I'm "THAT" guy Staff Member Global Moderator Moderator

    Messages:
    14,191
    That's going to be

    L
    O
    U
    D

    I can't wait !!!
    tcecil88 likes this.
  4. tcecil88

    tcecil88 .30-06

    Messages:
    1,181
    Uhh, yeah....
    I don't plan on it's maiden voyage to be to an indoor range. I will try to video it and post that.
    Last edited: Jun 21, 2019
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  5. tcecil88

    tcecil88 .30-06

    Messages:
    1,181
    With the parts I got today, a KAK Micro Flash Can and a UTG Pro 5.5" Keymod rail, I have made it as short as I dare to. I love the look, but shooting it is not going to be pleasant until I get the gas dialed in.
    Deplorable P 2.0 RS.jpg
    meanstreak likes this.
  6. John A.

    John A. I'm "THAT" guy Staff Member Global Moderator Moderator

    Messages:
    14,191
    the flash can may help some.
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  7. tcecil88

    tcecil88 .30-06

    Messages:
    1,181
    I finally made it to a buddy's outdoor range today to shoot the new pistol. First off, I went back to the original configuration of the 4.75" barrel with the Midwest 3" blast can and 7" forend, which I like better than the shorter configuration. I set the gas block to full closed and then opened it back up 2 full turns and locked it down. I tested the weapon at around 10 yards. The first shot of Aguila 5.56mm 62 gr. FMJ locked back the bolt on an empty mag and ejected the spent casing to 3:00. Next mag had 3 rounds and they went perfect. Then I put 5 more rounds in and had 2 double fires back to back, then the single round went and locked the bolt back. I fired 5 more rounds and had zero issues. I ride the trigger pretty tight on the reset and I believe that I bump fired it. I went to look at the target and found two for sure keyholes and one that looked like it started to keyhole. The group was large too. I figure the barrel is too short to stabilize the round at 4.75" and 1/7" twist. I went to Federal .223 55 gr. ball and ran around 30 trouble free rounds through the weapon all in a nice tight little group and more importantly, no more double fires and no keyholes. All rounds were ejected around 3:00. 55 grainers it is then.
    All in all, I am happy with the build. I feel the gas is set well enough and will begin sighting in the irons and red dot on the next range trip.
  8. John A.

    John A. I'm "THAT" guy Staff Member Global Moderator Moderator

    Messages:
    14,191
    One option that may have caused the double was the adjustable gas block.

    If the gas was turned down and the bolt didn't go back far enough to engage the disconnector, may have allowed hammer follow. As I'm sure you're aware is not good. But sounds like you have everything adjusted properly now and that's the only way to adjust it is to live fire, otherwise it's nothing more than a guess.

    The really short barrel probably isn't enough to stabilize the heavier bullets if you were noticing keyholing. That is a really short barrel for sure. Despite the faster twist rate. If it was keyholing with 62's, then the 55's are probably right on the threshold either way.
  9. tcecil88

    tcecil88 .30-06

    Messages:
    1,181
    I am going to try Lake City M193 and a couple other 55 gr. loads I have to see what it likes the best. Would it hurt to open the gas block up maybe 1/5 turn more?
  10. John A.

    John A. I'm "THAT" guy Staff Member Global Moderator Moderator

    Messages:
    14,191
    I don't know.

    Sounds like the ejection pattern (3 o'clock) is about right on. As long as it's cycling and locking the bolt back, that sounds like it's tuned the way it should be now.

    I'd just watch the gun and make sure it's functioning correctly if it were me. If it works right with the weaker ammo that you can use, it should be fine.
    tcecil88 likes this.
  11. tcecil88

    tcecil88 .30-06

    Messages:
    1,181
    That should have been 1/2 turn, not 1/5. Sorry about that.
    It's a fun little gun to shoot, not really practical for much with the short barrel and being a 5.56, but it put a smile on me and my buddies face today. I wanted to build a PDW and I think this one fits the bill better than my other AR pistol. I may swap around the shorter flash can and forend and see what I actually like better shooting. It won't make much different as far as the gas system goes, so might as well try it at some point.

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