OE-SPEC- 300 Blackout 4.75" Micro gas, AR15 Barrel- Nitride

When I hatched the idea to build a super short PDW style AR I was skeptical that the physics would allow for as tiny a build I was looking for. There were mixed feelings online about the micro style in general. But given the objective, the AR platform seemed to be the most workable solution... if it worked. My concern was lack of dwell time resulting in lack of direct impingement pressure and excessive post muzzle exit burn. I was confident I could at least make it work but I was also worried about the downrange performance. At first I was thinking 5.56x45 but when thinking it through realized I wanted to put some mass in the projectile and with a more favorable burn profile I opted for 300 AAC BO. That's when I found this barrel. This puts the overall length of my pistol at 20.6" and an overall weight with empty mag of 5 lbs 5.6 oz with red dot, buis, and Streamlight TLR-1 unloaded. With the halves separated the whole thing fits in a 5.11 4-Banger go bag. I have several Value Line barrels in builds and this one looks to be of the same quality. I was shocked at how big the gas port is drilled but was happy to see it since I wanted to make sure the gun cycled well. I opted for an adjustable block so I could reduce the reciprocating force of the bolt as much as possible, thus ideally combined with the huge gas port. After a quick assembly I took it out to the range with two different loads: (1) 168gr OTM over H110 and (2) 110 gr V-Max over Alliant 2400 to check the difference between the two outside profiles I wanted. First worked with the 168s and was pleased to print a 2" group at 50 yds. Then shot the 110s and it was basically like setting off a flamethrower. Quit those after 3 rounds. I'm going to be moving it back to 150 gr projectiles with both powders and see what the difference is again with the same bullet. But in both cases recoil was minimal and functionals were perfect. Overall I'm ecstatic. Both types of loads worked perfectly with no cycling issues and lockback of the bolt everytime. I just need to get the load fine-tuned and chrono'd and I'll have a PDW in a briefcase sized setup that's both reliable and adequately accurate. Also FYI, my PMAG did not work. Lancer did well, but most of the shooting was done with ETS.

Kak 4.7 barrel is definitely worth it. Just make sure you buy the gas block and tube if you dont have them.. Its the cheapest you’ll find anywhere for the great quality.

Works great but only with your micro gas tube. Gas hole is big enough to cycle with a suppressor.

Thank you all my parts came in less then 5 days from order this barrel is soooo tiny..... wish I could post a photo of my finished build