Need info on a AR pistol upper

[jeff43]

I'm gonna buy a pistol upper from PSA, but confused on what length barrel to get.I was going to go with the 10.5 inch,but would maybe a shorter one like the 7.5 or 8.5 inch.Will the shorter barrel lengths function like they are suppose to?Ice read that anything shorter than a 10.5 won't run well.

 

[lordjackel]

My opinion...if you reload then there is no reason a 7.5 or 8.5 can't be loaded to run very well (I recommend an adjustable gas block).  If you don't reload I don't recommend much shorter than 10.5"  factory ammo is tuned to function best in a 16" barrel...so going shorter means more back pressure and more carbon, gas, etc. going back into the action...so it gums up very quickly.  At least this is my experience...I have a 16", a 10.5 and a 7.5 and they run flawlessly but then I also reload specific to each of them.

[jeff43]

2 minutes ago, lordjackel said:

My opinion...if you reload then there is no reason a 7.5 or 8.5 can't be loaded to run very well (I recommend an adjustable gas block).  If you don't reload I don't recommend much shorter than 10.5"  factory ammo is tuned to function best in a 16" barrel...so going shorter means more back pressure and more carbon, gas, etc. going back into the action...so it gums up very quickly.  At least this is my experience...I have a 16", a 10.5 and a 7.5 and they run flawlessly but then I also reload specific to each of them.

I do reload,but wasn't planning on reloading for it.Probably just carry it in the truck and have it for plinking.I reload 223 mostly for accuracy in my AR rifles and 223 bolt guns.

So you don't think a 7.5 or 8.5 inch would be  dependable with Wolf of PMC Ammo?

[jeff43]

Not much traffic on here.

[Raoul]

I've got a PSA 8.5 and it's never been a problem. I've fired my loads, steel, and milsurp through it with no problem.

[jeff43]

17 minutes ago, Raoul said:

I've got a PSA 8.5 and it's never been a problem. I've fired my loads, steel, and milsurp through it with no problem.

That sounds good.i would be shooting steel case ammo mostly when target shooting. I don't like chasing down brass.Do you have a brace on yours?

[Raoul]

50 minutes ago, jeff43 said:

That sounds good.i would be shooting steel case ammo mostly when target shooting. I don't like chasing down brass.Do you have a brace on yours?

I do not.

[hipower]

I am thinking of doing a 9mm pistol form. Using PSA 7.5 upper, I don't see much need for a brace on it. But if all comes together as I hope, I'd think of using a brace on it to see if I'd like to go the SBR route for it.

I know I have other options instead of this, but it's been on my mind for a while. Kinda stuck in the cracks and I can't shake it loose.

[jeff43]

2 hours ago, hipower said:

I am thinking of doing a 9mm pistol form. Using PSA 7.5 upper, I don't see much need for a brace on it. But if all comes together as I hope, I'd think of using a brace on it to see if I'd like to go the SBR route for it.

I know I have other options instead of this, but it's been on my mind for a while. Kinda stuck in the cracks and I can't shake it loose.

I'll probably get a shock wave brace when I get mine together.I think that's the cheapest route.

[hipower]

40 minutes ago, jeff43 said:

I'll probably get a shock wave brace when I get mine together.I think that's the cheapest route.

That's true. And probably the best route for me. But...if I should got the SBR route someday, I have this little thought of using a minimalist stock on it.

I have one on a carbine and I really like it.

[jeff43]

10 hours ago, hipower said:

That's true. And probably the best route for me. But...if I should got the SBR route someday, I have this little thought of using a minimalist stock on it.

I have one on a carbine and I really like it.

The SBR's are fun and cool looking, I have a Krinkov I've had for years. It's just a PITA to do the paperwork and stuff for the stamp.

[hipower]

34 minutes ago, jeff43 said:

The SBR's are fun and cool looking, I have a Krinkov I've had for years. It's just a PITA to do the paperwork and stuff for the stamp.

Yes. Absolutely. That's what has been keeping me from doing a couple of things.

The cost and the time involved. Mostly the time to be legal on it.

Edited May 29, 2017 by hipower

[Tobashadow]

I built a 10.5 a couple years ago (and when I mean build I bought nothing assembled I did every pin from the BCG to the forward assist), it is setup with a carbine length gas system except with a much larger gas port. The barrel basically ends a half inch past the gas block but it will run on any ammo I have thrown in it including tons of Tula with not one failure. And it is nothing special I purchased everything as cheap as possible on sale everywhere to make a budget gun.

That's the shortest personally I will ever make myself.

[jeff43]

I was planning on getting this upper from PSA.

Barrel Length 10.5"

Carbine Gas System

Nitride finish Barrel

4150V Chrome Moly Vanadium barrel steel

5.56 NATO Chamber

1 in 7" Twist Rate

Chrome Lining - None

Barrel Extension:  M4

Hand guard Type: PSA Classic Polymer

F-Marked Front Sight Post

Muzzel Thread:  1/2-28

Muzzle Device:  A2 Flash Hider 

[Tobashadow]

All good specs, I would ask what size gas port it has.

This is the barrel I used - https://www.classicfirearms.com/arbarrel10-5m4parkerizedhbar1in8twist

AR-15 10.5" Contour Barrel, .223 WYLDE, 1:8, Parkerized

Premium Grade Parkerized AR-15 Contour Profile Barrel, 10.5",1 in 8 twist 
Gas port drilled for carbine length gas set up, and threaded for comp.
Barrel Extension in rear with M4 feed ramps... drilled with a .093" gas port opening at carbine length. It has a .750 gas block diameter,  ready to install into receiver.
.223 Wylde

[jeff43]

7 hours ago, Tobashadow said:

All good specs, I would ask what size gas port it has.

This is the barrel I used - https://www.classicfirearms.com/arbarrel10-5m4parkerizedhbar1in8twist

AR-15 10.5" Contour Barrel, .223 WYLDE, 1:8, Parkerized

Premium Grade Parkerized AR-15 Contour Profile Barrel, 10.5",1 in 8 twist 
Gas port drilled for carbine length gas set up, and threaded for comp.
Barrel Extension in rear with M4 feed ramps... drilled with a .093" gas port opening at carbine length. It has a .750 gas block diameter,  ready to install into receiver.
.223 Wylde

I emailed PSA about the gas port size.

[monkeylizard]

The 5.56/.223 loses a lot of its velocity in these shorter barrels. To me, anything below 10.5" is just too much of a loss to make it worth fooling with and even a 10.5" is a pretty significant loss over a 20-26" barrel, but YMMV. Plus, 10.5" barrels put the muzzle plenty close to my face when shooting it. I don't really want that blast any closer, but again, YMMV.

http://rifleshooter.com/2015/12/223-remington-5-56mm-nato-barrel-length-and-velocity-26-inches-to-6-inches/

[Oh Shoot]

57 minutes ago, monkeylizard said:

The 5.56/.223 loses a lot of its velocity in these shorter barrels. To me, anything below 10.5" is just too much of a loss to make it worth fooling with and even a 10.5" is a pretty significant loss over a 20-26" barrel, but YMMV....

I get 2525 fps and higher depending on cartridge from 10.5".

If you're worried about  max "lethality", use something besides FMJ. Even cheapest soft point ain't no slouch at that velocity. Pretty effective even with the further diminished velocities of even shorter barrels.

- OS

Edited May 31, 2017 by Oh Shoot

[monkeylizard]

True. I don't want to get shot with one out of a 1" barrel. 

[Johnny Rotten]

I have this one

http://palmettostatearmory.com/psa-stealth-7-pistol-length-5-56-nato-1-7-nitride-barrel-9-keymod-lightweight-rail-with-kak-flash-can-bcg-ch-516444638.html

I use a carbine buffer and LC193 or wolf ammo with no issues other than its really really loud

FWIW: 10.5 is good 11.5 is even better

 

 

[Oh Shoot]

16 hours ago, jeff43 said:

I was planning on getting this upper from PSA.

Barrel Length 10.5"

Carbine Gas System

Nitride finish Barrel

4150V Chrome Moly Vanadium barrel steel

5.56 NATO Chamber

1 in 7" Twist Rate

Chrome Lining - None

Barrel Extension:  M4

Hand guard Type: PSA Classic Polymer

F-Marked Front Sight Post

Muzzel Thread:  1/2-28

Muzzle Device:  A2 Flash Hider 

Probably same upper I used on my plain jane one, which has run like a top with everything I've put into it. I did use heavier buffer, but it also ran fine with standard carbine one too. More upright grip like the K models from Magpul highly recommended for these babies, much more ergonomic

Lives behind seat of my little truck in this, in case I need to tote it around at any point a bit discreetly.

- OS

Edited May 31, 2017 by Oh Shoot

[Dolomite_supafly]

18 hours ago, monkeylizard said:

The 5.56/.223 loses a lot of its velocity in these shorter barrels. To me, anything below 10.5" is just too much of a loss to make it worth fooling with and even a 10.5" is a pretty significant loss over a 20-26" barrel, but YMMV. Plus, 10.5" barrels put the muzzle plenty close to my face when shooting it. I don't really want that blast any closer, but again, YMMV.

http://rifleshooter.com/2015/12/223-remington-5-56mm-nato-barrel-length-and-velocity-26-inches-to-6-inches/

I am not sure I would trust that because it looks like the data is not correct. I mean two different loads, with two different bullet weights, have the EXACT velocity with barrels up to 14". Both M855 and M193 have the exact same velocities with barrels 14" and under, I think not. The standard deviation is also identical which is statistical equivalent of hitting all the lotto numbers, not going to happen. Heck, you could not get those results shooting bullets from the same box of ammunition in two separate strings, much less two different loads from different manufacturers.

Those results are worthless.

[monkeylizard]

Good eye. Not my numbers, just a random site I found on Google. I've seen similar ones before. The point was that .223/5.56 velocity is sensitive to barrel length. Most are, of course, but this one more than some others. I think you made the same point a few years back and that it was one reason why you liked AK pistols better than AR pistols because the 7.62x39 doesn't lose as much percentage of its velocity in shorter barrels. Do I recall that correctly?

[jeff43]

I'm not as much concerned about velocity as I am reliablity. Still trying to decide between a 8.5" or a 10.5" barrel. I like the 8.5 for being more compact.

Thanks for all the information and pics on this.

Thanks Jeff

[Wingshooter]

I have an 8.5" AR pistol in 300bo. I really like the size and feel. I should be getting my can out of jail for it soon, and that will make it even better. Mine's 300, but it's been 100% reliable so far with about 850-900 rounds.

SLR handguard, Shockwave brace,TGO billet upper and lower

 

Edited June 1, 2017 by Wingshooter