Super Short Upper.....9mm or 300BLK?

[Tim]

I picked up one of the blem MVB PDW style stocks last week and am trying to decide what to do with it.

If you wanted a super short - 4-5" - lower would you go 9mm or 300BLK?

I already have a couple SBR lowers that can be used for the build. I also have 9mm mag block and bolt on hand, so the decision between 9mm and 300BLK is not a matter of cost.

If I go 9mm, it would pair with a Form 1 can (13 oz, 6" OAL)
300 would pair with an AAC 762-SD (23oz, 9" OAL)

So...doing the 9mm saves me 3" right off the jump because of the can. Although, now that I think about it, I could probably run that F1 can with 300BLk with no trouble. It's all Ti save for a steel valve spring.

I'd definitely leaning towards 9mm, but thought I'd throw the option out there and see what y'all suggest.


Edit: I have 10.5" uppers for both 9mm and 300BLK already on hand. This is an additional upper just for giggles.

 

[BowWow]

9mm cheaper and less problems in general.

 

[NCFubar]

4”-5” length is 9mm to me ... .300BO is 8” or so minimum to me.

 

[bigfelipe]

Need 8" minimum to stabilize 300blk so it's a no-brainer... 9mm...

 

[Jerzsubbie]

Right to Bear just released a 6" .300 BLK barrel for $130 (
https://www.righttobear.com/Right-To-Bear-6-300-Blackout-Barrel-p/rtb3006m.htm
), but being 1:7 twist, I'm skeptical how well it'll stabilize subs. Unless you can get your hands on one of those rare HB barrels with a 1:5 twist, I'd say 9mm.

Since this is a fun gun, I definitely say 9mm. Easier to build that short, more reliable at that length, much cheaper ammo (esp if reloading), and you can use your shorter can.

 

[JRHorne]

Ballistic Advantages had their 4.5" 9MM barrel for like $86 a few weeks ago. I love my 4.5" 9MM.

 

[Tim]

Ballistic Advantages had their 4.5" 9MM barrel for like $86 a few weeks ago. I love my 4.5" 9MM.

View attachment 58651

That's a 4.5" barrel? With what muzzle device (length?) and hanguard? That's pretty much what I'm going for.

 

[JRHorne]

It has just a basic ass thread protector on it and the handguard is the 4" Samson Star4 quad rail that was hard as shit to find.

https://lapolicegear.com/samson-star-4-rail.html

And now of course I can find them everywhere as I Google.

 

[patina]

It has just a basic ass thread protector on it and the handguard is the 4" Samson Star4 quad rail that was hard as shit to find.

https://lapolicegear.com/samson-star-4-rail.html

And now of course I can find them everywhere as I Google.

What sights are those?

 

[JRHorne]

What sights are those?

Aero Precision

 

[BatteryOaksBilly]

Ballistic Advantages had their 4.5" 9MM barrel for like $86 a few weeks ago. I love my 4.5" 9MM.

View attachment 58651

That's a damn good looking blaster!!!!

 

[JRHorne]

That's a damn good looking blaster!!!!

Yea I really like it.

 

[BatteryOaksBilly]

I have some 223s and a BLKOT but no 9. …….Probably need to fix that.

 

[Chuckman]

I really want a 9mm SBR...since I will never have a for-real H&K MP5....

 

[JRHorne]

I really want a 9mm SBR...since I will never have a for-real H&H MP5....

My SBR Scorpion helped me realize that if I wanted subgun fun, 9MM was the way to go. I need to get off my ass and get a can...

 

[Tim]

I really want a 9mm SBR...since I will never have a for-real H&K MP5....

The build that I started this thread for will use one of my SBR'd lowers and Form 1 can. It's already a 9mm SBRin fact, but it's 10.5". I'm really wanting this super short setup for giggles. I've put all of the required components in a couple shopping carts waiting to see who has the best Father's Day deals.

 

[BatteryOaksBilly]

Better than drawers, socks, and ties!!!!!!!!!

 

[JohnFreeman]

My SBR Scorpion helped me realize that if I wanted subgun fun,a SWD M11 with a Tungsten heavy bolt was the way to go.

Fixed it for you!

 

[JohnFreeman]

The build that I started this thread for will use one of my SBR'd lowers and Form 1 can. It's already a 9mm SBRin fact, but it's 10.5". I'm really wanting this super short setup for giggles. I've put all of the required components in a couple shopping carts waiting to see who has the best Father's Day deals.

Post what you find!