First 300 Blackout Build

[Ape_Factory]

Been waiting on this one to come to fruition for some time. My form 1 was finally approved last month and I recently assembled everything after shopping for the desired components over the course of six months. Once assembled, I realized I needed to check the headspace and had to locate gauges. It took a bit to find go/no go gauges and bought those at a modest premium instead of waiting for less expensive options.

A few thoughts on some of the components. I have a 16" 5.56 upper build and I'm using one lower for it and the 300BLK upper. Both upper builds are using the same brand/model of upper receiver, V Seven G4, and same barrel manufacturer and spec, match grade Faxons, gunner profile.

The 300Blk is a 10.5" Faxon match grade gunner profile barrel with a Smoke Composites hand guard while the 5.56 is a Faxon 16" match grade gunner profile barrel and a Coda carbon hand guard. Both are using a V Seven G4 upper (cheapest option they make). Was a interference fit in both situations so if you use a VSeven M4 GI upper with an Faxon barrel, you'll need to freeze the barrel and heat the upper receiver.

IMO, the Coda is the more precise hand guard in terms of barrel nut and clocking of the hand guard. The Coda's system, which uses a separate barrel nut and a trunnion which fits over it, allows the proper clocking of the hand guard where the Smoke, if torqued correctly, uses a one-piece barrel nut/hand guard mount with threaded holes and could cause the upper rail to be off. If you purchase the Smoke hand guard with the upper rail (a cost option), it may or may not line up with the upper's rail exactly depending on your torque specs. So if you torque the nut down to say 40ft. pounds, the screw holes may be clocked in such a way that once you slide the hand guard on, the top rail may not line up properly. It could be ever so slightly off.

In addition, I had to machine out a portion of the Smoke hand guard on the inside radius, otherwise it would not fully slide into place. Looks like whatever milling tool they used to hone out the inside didn't quite go far enough. I'm sure that's not the norm but given the cost, these details should be taken care of. It was fairly easy to grind down with a Dremel. Took me all of 10 seconds.

With the Coda, being a two piece barrel nut with a trunnion, you'll always get a proper alignment. With that said, the Coda does not come with an integrated top rail.

The other major difference between the two uppers is the BCG. I have an RCA titanium BCG with a POF roller cam pin in the 5.56 upper. I waited forever and a day for those to come in stock again for the 300 BLK upper with no luck. I gave up after four months and zero replies to email inquiries. Rainier Arms has their own Ti BCG which is within 1/10th of an ounce so I went with it and converted it to a POF roller cam pin. This allows me to use the same buffer system as they're almost identical in weight. Both uppers have SA adjustable gas blocks and both will be shot suppressed once the can arrives.

The finish of the Rainier Arms BCG and the RCA BCG have diferences. The RCA is much more slick-feeling, requires almost no lube and is super easy to clean. We'll see how the Rainier compares. Both are "nitrided" but the RCA is a different formula and IMO, worth it. The Rainier is a "standard" nitride finish from what I can tell and does not feel nearly as slick to the touch.

The 300 BLK weighs just south of 5 pounds sans scope and magazine, almost identical to the 5.56 with a longer barrel.

I'm still waiting for a suppressor before heading to the range to dial it in. I have about half a dozen different ammunition brands/weight. Some sub, some super. Planning on loading ONE super and ONE sub to keep it simple but will keep an open mind. Hornady VMax 110 grain for supers (since I have a bunch) and Hornady 190gr Sub-X for well, subs. IF I can find the Sub-X bullets that is. The Sub-X rounds have recently come into stock so I'm hopeful the bullets become available soon. I even managed to find H110 in an 8-pound jug and have some CFE Black as well.

I have to say, shooting it is almost anti-climactic at this point due to ammo/reloading shortages. Normally I'd be out the door and headed to the range within 10 minutes of finishing a build. I almost feel guilty knowing how short-lived the euphoria could be knowing new ammo won't be easy (or cheap) to come by. Hoping the rifle lives up to my expectations and the exponential wait times it took to get it built!