300blackout build, what you know like and dont

[nagantguy]

I was thinking of getting an encore barrel in 300blackout just to play with and use as a garbage disposal for anything the ar didn't digest properly. They have a 22 inch threaded stainless one for like $220. The encore being in my top 5 weapon systems I thought why not.

[Electric88]

I'm assembling my lower now, I thought this caliber which I can readily make brass, and already have several molds for couples with PC would be awesome and very useful as deer pigs yotes and garden pests are my main quarry and 6 years of service training/familiarity with the ar platform, the build is a go! Thanks you guys for being my enablers once again.

Like reloading and casting, assembling ARs can be quite addicting. I built my first thinking I would just do one and be done, but 3 years and 4 ARs later I'm still contemplating what next.

We all need enablers, and at least it's not drugs

[xacex]

Like reloading and casting, assembling ARs can be quite addicting. I built my first thinking I would just do one and be done, but 3 years and 4 ARs later I'm still contemplating what next.

We all need enablers, and at least it's not drugs

6.5 Grendel

[Electric88]

6.5 Grendel

I've thought about building a 6.5 Grendel, but haven't looked into it too much. I probably would build one, if it was possible to form brass from a more common caliber and cast boolits for it. Not sure if that's possible though

[2wheelDuke]

6.5 Grendel

Grendel is a bad *** round, but like others have said, brass isn't easy to come by, and it doesn't appear very cast friendly. And it needs a special bolt head.

I'm not made of money, and I don't need the long range performance. So for me, .300 is the answer in the AR-15 platform.

[nagantguy]

Exactly how I feel, the exotic calibers are cool and interesting and serve a purpose but having to pay a kings ransom for brass isn't an attractive option to me, if I need long range thundrbolts, I have a very old very used Weatherby in 300weatherby. The idea for my blackout is close quiet work with a little more smack than .223.

[Electric88]

Yup. That was my reasoning for the blackout as well. On a side note, Michigan just passed a law to allow hunting with suppressors yesterday. Just one more reason I'm glad to have built a blackout and ordered a suppressor

[2wheelDuke]

I just fired my latest Blackout build for the 1st time. I actually built 2 different uppers with the same config, a 5.56 and a .300 blackout.



On the plus side, it went bang every single time and cycled. It was great with jacketed, but my cast loads weren't accurate at all. Back to the drawing board there. Time to load up more and try them with my other guns as well.

[wlc]

I was thinking of getting an encore barrel in 300blackout just to play with and use as a garbage disposal for anything the ar didn't digest properly. They have a 22 inch threaded stainless one for like $220. The encore being in my top 5 weapon systems I thought why not.

I did the same exact thing. Started with an AR in 300blk and decided I wanted even quieter so bought a Bergara barrel for the Encore. It is almost hollyweird quiet with subs. I don't have to worry about cycling, lets me use many more powder and bullet combinations as well.

That all said, I'm also contemplating another AR upper build. I'm on the fence about it though as I want a short upper so will have to do the whole tax stamp thing again. I hate waiting. Wish they could change the laws so it was a much shorter turn around time on tax stamps, especially if you are already in that system with other items.

[xacex]

I've thought about building a 6.5 Grendel, but haven't looked into it too much. I probably would build one, if it was possible to form brass from a more common caliber and cast boolits for it. Not sure if that's possible though

7.62x39 brass can be formed to 6.5 Grendel. I do cast for it too. Just load up a staring load with a cast bullet, and it blows the case out to the proper dimension. The 6.5 Grendel is more suited to cast than a 5.56. Another option is the 6.5 PCC. That one is made from 5.56 brass, but does not reach the velocity of the 6.5 Grendel. Close, but not quite. Better suited for a 100 grain or less bullet weight too. I use the bullet Von Gruff designed that NOE sells.

[xacex]

I just fired my latest Blackout build for the 1st time. I actually built 2 different uppers with the same config, a 5.56 and a .300 blackout.



On the plus side, it went bang every single time and cycled. It was great with jacketed, but my cast loads weren't accurate at all. Back to the drawing board there. Time to load up more and try them with my other guns as well.

Nice Dissy build! I did one myself in this style. Used an A2 carry handle upper, and standard A2 rifle hand guards. Had to go with the adjustable stock however. The A2 length stock is uncomfortable to me. I tried an A1 stock, and prefer that length.

[6bg6ga]

Built 3 300 blackouts as of last month. The first one I purchased a stripped upper from radical and picked up bolt and charging handle to complete my upper. The lower I put together myself. The second and third 300's were built entirely by me selecting my own parts. All three have pistol gas systems and no adjustable gas blocks as my experience with the first one told me I didn't need and adjustable block. My opinion here and I'm sure others will offer different opinions. Extremely accurate with anything I put in the magazine.

[guicksylver]

7.62x40. Far better.
Think and look outside the box.

[dragon813gt]

7.62x40. Far better.
Think and look outside the box.

Doesn't use stock magazines.

[popper]

Had a problem with jams yesterday - IMHO caused by over crimping with FCD. MINE appears to be tapered (not stepped like 30/30). Over crimp pushed alloy down the neck - mouth is 0.329ish, mid neck is 0.335 (max and over 0.333 of chamber). Boolit at mouth is still 0.3085. Just changed lock ring to Hornady from Lee, evidently too hard a crimp. Yuck - get to pull 60 rnds.

[bruce drake]

I had a 300BLK built 4 years ago and I enjoyed it a lot and recommended it to others but eventually I wanted to have a bit more powder selection for reloading super-sonics that the H110, W296 and AA1680 powders. I eventually recut the chamber to 30-223 which required me to add a carbine length pigtail gas tube to the pistol length gas system and move to an H3 buffer along with a quick modification of the magazine (dremeled out the shoulder indents on the standard magazine) and now I have a 45mm cartridge case that handles 110 and 120gr bullets with equal capability with 7.62x40 ballistics without the need to trim the cases down.
Would I build another AR upper in 300BLK. Yep. Great little cartridge. But right now I'm still having too much fun with the original 30 Apache (30-223) cartridge platform.

[2wheelDuke]

I had a 300BLK built 4 years ago and I enjoyed it a lot and recommended it to others but eventually I wanted to have a bit more powder selection for reloading super-sonics that the H110, W296 and AA1680 powders. I eventually recut the chamber to 30-223 which required me to add a carbine length pigtail gas tube to the pistol length gas system and move to an H3 buffer along with a quick modification of the magazine (dremeled out the shoulder indents on the standard magazine) and now I have a 45mm cartridge case that handles 110 and 120gr bullets with equal capability with 7.62x40 ballistics without the need to trim the cases down.
Would I build another AR upper in 300BLK. Yep. Great little cartridge. But right now I'm still having too much fun with the original 30 Apache (30-223) cartridge platform.

I'd like to know more about the 30-223. What bullets/boolits are you using? I'm assuming they fit an unmodified AR magazine? Seems like necking up would be better than the whole trimming routine, with the advantage of more case capacity.

[bruce drake]

they don't fit the unmodified magazine. I had to cut out the area (stabilizing rib) that is indented on the front sides of the magazine with a dremel as the neck is 30 cal and not 22. I'm using 110gr Rn and 110gr Spitzers along with 125gr spritzer bullets in jacketed. In cast, I use 311359 (115gr gas checked spire points) and 311410 (130gr plain-base Spires)

[nagantguy]

Went and window shopped for a can (suppressor) today, really liked the sig. Think I've selected my upper and butt stock. Been cutting brass in my free time and having a blast picking and choosing components..none of my other ar builds have been this much fun!

[destrux]

About the only thing I don't like about my 8.5" blackout SBR is that I never shoot it without a brass catcher because the brass is expensive, and beyond 125m the bullet drop is extreme for the subsonic ammunition that I primarily use (with my rifle being suppressed). Full power ammo is on par with the 7.62x39 but it benefits from a selection of better bullets being a .308" bore. Jacketed bullets are expensive compared to 9mm and 5.56, but if you only shoot coated cast that doesn't factor in much then. I shoot mostly powder coated Lee 230gr in mine. I just got a Lee 155gr 7.62x39 mold though and I plan to use that for the blackout too (resized to .309").

The blackout is great for cheap cast bullet loads though. My cheapest reload is coming in at about 8 cents per round right now. That's using free lead to cast 230gr bullets, 10.5gr of powder ($27/pound), primers at $25/K, and getting 10 reloads out of a piece of brass before it's toast (brass costing $100/1000).

The super long 200+ grain bullets also retain velocity and energy extremely well. There's barely any energy lost at 100m, compared to a 230gr .45ACP fire from a carbine that loses a significant amount of energy by time it gets to 100M. They also penetrate very very well.