Solo 300 - a lightweight manually operated .300 BLK SBR

[HeavyDuty]

@jandbj started a thread about a ultralight manually cycled AR based 7.62x39 rifle he was building, and it got my wheels turning.

There was a guy I saw a few times back at my gun club in NH who had something similar in .300 BLK. He wasn’t very social, but if I remember correctly it was a right hand charger and had a 9” or so barrel, pistol configuration. It looked like a lot of fun.

I have an underutilized SBR - a 7.5” 5.56 with a lightweight Sabertube based stock on a LAW folder, my “ASBO” as a British friend calls it (Anti Social Behavior Order) because I can clear a range in five shots with it. Huuuge pumpkins of flame and flash-bang level concussion. It’s stupid, but stupid can be fun - and the amnesty turned it into a SBR. Why not make this lower multipurpose?

I picked up a Solo 300 upper and 9” .300 BLK barrel without handguard and added a 7.25” Kaw Valley CF tube. I don’t know what I’ll do for an optic yet, the idea is a vest pocket rifle to use at least occasionally with a suppressor.

Making an optic choice should be interesting since I don’t really have a well defined use case for this. It is a budget build, so nothing too crazy. I figure either a very lightweight 1-4x or so (preferably with illumination) or one of the PA 3x prisms. Any suggestions?



jandbj’s project that inspired mine: https://pistol-forum.com/showthread....erated-7-62x39

[nate89]

I still have my solo 300 upper, and actually really enjoyed shooting it. I bought the 6" barrel he sells several years ago and did the same cut down BCA carrier in the 7.62x39 thread. It was a great project for reloads; I shot everything from 85 grain Hornady XTPs with trailboss (works very well with small varmints and is very quiet through even a short can like my omega 9k), full weight 200-220 grain subs, Barnes and Nosler 110 supers, coated and plated bullets, and just about everything else I could find to test. The 110 grain bullets kept a decent amount of velocity for a 6" barrel. It isn't something I shoot very often, but it is a lot of fun to take out and plink with.

[HeavyDuty]

One thing I need to do is find a rubber something to put in or on the charging handle - the stock interferes with it pretty hard.

[jandbj]

One thing I need to do is find a rubber something to put in or on the charging handle - the stock interferes with it pretty hard.

Heat shrink tubing perhaps?

Bet if you lost the law folding mechanism, you’d be under 4lbs.

[HeavyDuty]

Heat shrink tubing perhaps?

Bet if you lost the law folding mechanism, you’d be under 4lbs.

I’m thinking more of a rubber stopper. I don’t want to reconfigure the lower, I’m not chasing ounces.