Practical Personal Observations On The AR Platform .300 Blackout Truck Gun (update 5-28 with photos and minor revisions)

via Practical Personal Observations On The AR Platform .300 Blackout Truck Gun (update 5-28 with photos and minor revisions)

 

This is a pretty good writeup of one man’s Franken-300BLK. I haven’t worked with barrel blanks yet, but it doesn’t sound too difficult.

One Reply to “Practical Personal Observations On The AR Platform .300 Blackout Truck Gun (update 5-28 with photos and minor revisions)”

  1. Thanks for the link!
    I can tell you from personal experience Green Mountain’s chambered AR blanks are a wonderful wicked reasonably priced custom barrel resource. I’ve also built a .556 AR and a AR10 in .308 using GMRB chambered blanks. Nothing I have is as accurate as those barrels.
    I made a steel wear plate target and shooting at it with the .300 blackout AR, Troy iron sights, at 100 yards on Sunday. Steady, thru two 20 round box’s of Hornady Black 110 Grain, as quickly as I could get a nice sight picture on the front pin lined up, I made a 3 inch ragged circle with 40 rds, no fliers. Basically a quick combat sight picture, thinking if I was in a combat shootout, that would be my preferred rate of accurate fire. Very confidence inspiring results.
    The AR in .556 had a generic barrel, with an Aimpoint patrol optic, until I swapped it out for the GMRB chambered blank, it is a totally different carbine now. A few quick standing freehand shots to get the Aimpoint close to zero, the gun never shot so well. I finished machining it Sunday night, probably test it good by weeks end.
    I’m dialing these blanks in at .0003-.0002 for the muzzle crown and threads. Its worth the extra time setting them up in the lathe.
    Been making Thompson Contender barrels using their gunsmith’s unturned OD barrel blanks. Aside from the ridiculously inexpensive cost, again, I’m getting crazy levels of accuracy. I have no idea what they are doing up there in Conway NH. but it works. Using Manson piloted reamers, dialing in the chamber ends at no more than .0002 runout. I think the accuracy obtained pays off very well the time spent.
    I can’t recommend Green Mountain’s blanks enough. Good bunch of guys to do business with.