AR15 Shorty

[Albroswift]

Sprinco Hot White, H2 buffer, non adjustible gas block. Fired a couple rounds in the basement this evening, feeds correctly and LRBHO. Couldn't tell where it ejected, ping ping pingggg. Need the optics to show up and the range to open! 

[shooterrex]

Nice

[Cliff R]

Built this one last night.  The carry handle and front sight are temporary, going to order a holographic or red dot type sight for it today, and some back-up sights.....

[Albroswift]

Way Cool. If everything shakes out I'm going to dump the money on a LAW folder. I really like the look of the deadfoot but looks like some complicated $hit and enough money for another build. 

[Lowlander]

I've been down the 7.5", 5.56 road before, they are a pretty cool little set up. But yes, they will jar your head without something to direct the concussion forward. With an A2 you'll feel like yours eyebrows may get burnt off, lol...

I ran a KAK flash can on a 7.5" 300blk. It did ok directing the blast forward. Your gas port seems to be about right. You'll want it to be small as possible by the time your done tuning most likely. I do recommend a pigtail gas tube. As far as muzzle devices go, I went this route:

https://www.primaryweapons.com/product-url-5232

The CQB was the best muzzle device hands down on my best running 7.5" 5.56. It was a Pac-Nor barrel spec'd to Noveske Diplomat specs, I can't remember the gas port size but it was definitely on the small side. If you want, I can contact the gentleman I sold it to and get the dia. Out of 3 7.5" 5.56 barrels I've owned over the years that Pac-Nor ran better than any other hands down.

Another good muzzle device option I meant to try was a Surefire Brake with a Surefire QD Warden attached. Pricey but I imagine it would help. The direct thread Surefire Warden may also. I sold my 7.5" off and now the shortest I run is a 10.5" 5.56. 11.5" is the sweet spot for SBR. 

Edited April 18, 2020 by Lowlander

[unforgiven]

I'm really liking these Shorty's. 

[Albroswift]

45 minutes ago, Lowlander said:

I do recommend a pigtail gas tube.

I have one, but it doesn't fit inside the hand guard. I was thinking of installing on a different gas block and giving it a try without the handguard, but things seem good with the regular pistol tube. 

https://www.primaryweapons.com/product-url-5232 

is that a timing detent I'm looking at?

Edited April 18, 2020 by Albroswift

[Albroswift]

46 minutes ago, unforgiven said:

I'm really liking these Shorty's. 

Follow me down the highway of irresponsible decisions and take exit 7.5...

[unforgiven]

Damnnn if you hit the brakes to hard I'm gonna hit ya  . Those setups are badass

[Lowlander]

6 hours ago, Albroswift said:

I have one, but it doesn't fit inside the hand guard. I was thinking of installing on a different gas block and giving it a try without the handguard, but things seem good with the regular pistol tube. 

https://www.primaryweapons.com/product-url-5232 

is that a timing detent I'm looking at?

It is a locking detent that keeps the end from threading its way off during firing. They made 2 versions, the one pictured is the Gen 2 CQB. I actually had the Gen 1 CQB but they are functionally identical.

The Gen 1 has a "Krinkov" looking front end vs. the Gen 2 has full squared prongs. The purpose of the threaded end cap is so that you can disassemble and clean the carbon out of the inside of the brake. The detent keeps it locked in place. You can time the brake via shims or a crush washer. 

A trick I use is, I'll take a crush washer and lay it flat on a flat file and just slide it back and forth, removing material from the chamfered side until the brake/flash hider times into the correct position once torqued. It's a little time consuming and tedious, but using this method I can time just about any muzzle device with a crush washer in 30min or less without shims. You just remove material from the back of the crush washer until the muzzle device is properly timed.

My CQB brake was definitely the most effective brake I used on any of my 7.5" builds. The design of it acts similar to the blast chamber of a suppressor. While not fully sealed as a suppressor would be, my thought was it would be the closest I could get to that without running an actual suppressor. Most cans aren't going to handle the abuse of that 7.5" blast and risks a baffle strike from bullets that don't fully stabilize in the short barrel...

Edited April 18, 2020 by Lowlander

[dpete]

Sometime I should take the 10" suppressor of my 8" barrelled 300BLK and post up a picture of it with the flash/blast can on it.  Without the suppressor its one short little mo fo.

[Cunuckgaucho]

From 2019 Fall Shoot, luck pic catching both rifles firing. If you look carefully you might notice a bit of a difference.

[sketch]

Thats the fuckin R2 desert star! It comes around every couple of years and is shinning bright as day! Dont blink or you will miss it. 

[Matt.Cross]

2 minutes ago, sketch said:

Thats the fuckin R2 desert star! It comes around every couple of years and is shinning bright as day! Dont blink or you will miss it. 

Only if you're stone deaf, which you might be after Ron empties a mag or so. 

[Cunuckgaucho]

11 hours ago, Matt.Cross said:

Only if you're stone deaf, which you might be after Ron empties a mag or so. 

... but the stars you see even after you close your eyes make it all worthwhile. 

[Rsquared]

11 hours ago, sketch said:

Thats the fuckin R2 desert star! It comes around every couple of years and is shinning bright as day! Dont blink or you will miss it. 

Nah....the MK18 is a staple at this point. It shows up in the desert every fall. That thing is pretty much my go to rifle.

11 hours ago, Matt.Cross said:

Only if you're stone deaf, which you might be after Ron empties a mag or so. 

Yeah, that little bastard can get a little loud at times.

43 minutes ago, Cunuckgaucho said:

... but the stars you see even after you close your eyes make it all worthwhile. 

No $hit right? That thing blinds you after the first shot when it's dark.

[Cliff R]

Reminds me of the first night firing we did with the "new" (at that time) M-9 pistols.  They messed up and purchased TZZ ammo for them in 64 round boxes.  Turns out that stuff was for UZI's and just a fuzz too hot for the M-9's.

 

I've settled on 10.5" barrels for my "shorty" builds.  They "bark" loud enough and sizeable "fireball" at night or in low light conditions.  Got busy over the past few days and still working, will have to test fire my new build tomorrow.........Cliff

PS:  I know it's out there someplace but does anyone have a link to "barrel length vs velocity" from the 5.56's?  Just curious how much you loose going clear down to 7.5".......

Edited April 20, 2020 by Cliff R

[98Z5V]

14 hours ago, Cliff R said:

PS:  I know it's out there someplace but does anyone have a link to "barrel length vs velocity" from the 5.56's?  Just curious how much you loose going clear down to 7.5".......

I've posted it here before, but I have no idea what topic it's in. 

There is a minimal, regular velocity drop, per inch, down to 11.5" 5.56 barrels. When you drop one more inch, down to 10.5", there's a significant drop in velocity.  11.5" is the lowest I said I'd ever do - but then I built a 7.5".

[Cliff R]

I haven't dropped down to a 7.5" build yet, my wife told me she doesn't like short ones!.......LOL.....

[Cunuckgaucho]

14 hours ago, Cliff R said:

I haven't dropped down to a 7.5" build yet, my wife told me she doesn't like short ones!.......LOL.....

Instead of 7.5 in tell her it's 19 cm( just mumble this part) 

[392heminut]

On 4/20/2020 at 11:45 PM, 98Z5V said:

  11.5" is the lowest I said I'd ever do - but then I built a 7.5".

That's 'cause you get bored easily!!!

[Cliff R]

Update, made a few changes....spending a little more of my relief check.....I think I'm done with this one now.....

 

[unforgiven]

Good looking rifle brother 👍

[Cliff R]

Thanks.  My first Romeo 5 and I'm liking it so far.  Compact, looks good and comes on with movement.  I'm going to do some shooting this weekend, three rifles to sight in, two of them are "stubbies".........Elena is going with us.

I'm going to compare the Eotech I purchased recently against the Romeo 5.......

[sketch]

im a fan of the Romeo.. 5 👍🏻 little ones get bigger by packing ammo. 🇺🇸😁