AR Pistol Build ?s

[sgreen3]

Didn't really know which section to put this one in, so mods feel free to move if needed.

Im looking to build a 5.56/223 upper and would like to know what some of you guys do to make them reliable. My question is for those that have them or have built them, what have you done to make the cycle and function correctly. Im looking to build one to have for my suppressor when it comes in and also will end up SBR it as well. Thanks for the info fellas!

 

[mammynun]

I have a 7.5", 10.5", 11.5" and 12", all of which are 5.56x45mm. The 7.5" is the only one that required any "tuning" for reliability. The "tuning" consists of a heavier recoil spring (Sprinco "Blue") and an H3 buffer. This combo shoots NATO ammo, but it won't reliably cycle Tula/Wolf or low(er) powered .223 unless I swap the spring and/or buffer.

I'd be happy to come up sometime with them; it's easier to see and feel the differences than to explain them...

 

[dudley0]

My 10.5 has had no problems. Haven't gone shorter tho.

 

[M67]

When I had my 10.5" 5.56 pistol, carbine length gas system, it was 100% with a standard buffer and spring. That was with factory loads and my reloads

Only shot it a couple times without a muzzle device and it worked fine as well, I then put a PWS CQB on it then a suppressor

 

[throttletony]

as shown above, the general consensus is that barrel lengths around 10" + require less tuning.
If you'll run it suppressed, especially, most suppressor manufacturers recommend 10" +

*side note, if you weren't running a suppressor...
A pistol build in 5.56 is fine, but you lose a lot of energy and gain a lot of concussion/noise/flash.
Considered a 300blk?

 

[throttletony]

I have a 7.5", 10.5", 11.5" and 12", all of which are 5.56x45mm. The 7.5" is the only one that required any "tuning" for reliability. The "tuning" consists of a heavier recoil spring (Sprinco "Blue") and an H3 buffer. This combo shoots NATO ammo, but it won't reliably cycle Tula/Wolf or low(er) powered .223 unless I swap the spring and/or buffer.

I'd be happy to come up sometime with them; it's easier to see and feel the differences than to explain them...

mammynun is right on the money here. IF any tuning is required, usually a buffer & spring swap covers it, if not, then look to gas issues (use an adjustable gas block if possible), some people run those pigtail gas tubes, but I hear that they're about 50/50 for helping/hurting the situation

keep us posted!

 

[sgreen3]

I have a 7.5", 10.5", 11.5" and 12", all of which are 5.56x45mm. The 7.5" is the only one that required any "tuning" for reliability. The "tuning" consists of a heavier recoil spring (Sprinco "Blue") and an H3 buffer. This combo shoots NATO ammo, but it won't reliably cycle Tula/Wolf or low(er) powered .223 unless I swap the spring and/or buffer.

I'd be happy to come up sometime with them; it's easier to see and feel the differences than to explain them...

Awesome, heck yea Id like to take you up on that. I wont lie though Ill probably end up running a fair amount of Wolf through it since that's what I shoot the Run-N-Gun with. What buffer spring combo did you use to get that to cycle reliably?

 

[sgreen3]

as shown above, the general consensus is that barrel lengths around 10" + require less tuning.
If you'll run it suppressed, especially, most suppressor manufacturers recommend 10" +

*side note, if you weren't running a suppressor...
A pistol build in 5.56 is fine, but you lose a lot of energy and gain a lot of concussion/noise/flash.
Considered a 300blk?

Yea actually I'm selling my 300blk stuff right now in the classifieds. At this time I just don't feel like taking on another caliber to load for. I have barley enough time to load for my bolt guns much less another caliber for a semi auto platform. That's what I've heard though about the 5.56 pistols is their loud and kind of unruly which is why I'm thankful my stamp should be back soon so at least that should tame it down a little.

 

[mammynun]

Awesome, heck yea Id like to take you up on that. I wont lie though Ill probably end up running a fair amount of Wolf through it since that's what I shoot the Run-N-Gun with. What buffer spring combo did you use to get that to cycle reliably?

I never tried to get the 7.5" to work 100% with Wolf-ish ammo, but I'm willing to try and find out... I have buffers from standard carbine to H3 and several flavors of springs. I suspect that an H3 buffer with a standard spring will be in the ballpark.

Here's the 7.5" compared to the 11.5", I'll bring all my shorties to play with as long as you haul them in the trailer! LOL

 

[mammynun]

dbl tap

 

[sgreen3]

I never tried to get the 7.5" to work 100% with Wolf-ish ammo, but I'm willing to try and find out... I have buffers from standard carbine to H3 and several flavors of springs. I suspect that an H3 buffer with a standard spring will be in the ballpark.

Here's the 7.5" compared to the 11.5", I'll bring all my shorties to play with as long as you haul them in the trailer! LOL

Consider the tractor fueled up am the trailer hooked up

 

[rj3438]

Gas port size can be a factor also. I had a 10.5" with a smaller port that I opened up slightly so that it would consistently work with wolf.

 

[sgreen3]

I'll have to look into that. I have heard the gas port could be an issue.

 

[VSP1340]

These uppers will eat anything and be 100% reliable. PWS MK107. Awesome company too.

 

[DeanSports]

I have built tons of upper receivers. On pistols I have built more 10.5 than 7.5. I have found that you can built the uppers EXACTLY the same and some will cycle correctly and some wont. About 90% of the time it is a buffer issue. Just go with a heavy buffer every time and it will more than likely fire correctly.

As a few have already mentioned, 7.5 will give more trouble than the 10.5. Personally I think 10.5 is perfect.

 

[SnoopLoggyDog]

Built this with an 11.5 inch barrel from MAS Defense. Thought about shorter barrels, but I wanted reliability without an adjustable gas block or tuning buffers. I also wanted it to work with different makes of ammo.

It was also an exercise in how cheap I could built a basic AR pistol. Started with a PSA stripped lower and blemished Anderson lightweight upper. Most of the parts were leftovers from other projects and a few items from Ebay, ect. Free floated the barrel and mounted a light on the left. Has a KAK Flash Can to keep the muzzle blast directed down range. Runs great and is easy to maneuver.

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[avboiler11]

I have a 10.5" AR pistol with carbine gas built off an upper kit from Red Barn Armory.

It is 100% with a carbine buffer running Wolf 55gr up to XM193 and Mk262 clones, and if anything is a bit overgassed - especially with hotter 5.56 pressure ammo. An H2 buffer has moved ejection back toward 3 o'clock some, but really so long as it runs reliably (and it has) I don't care where the brass falls.

Once my can gets out of jail, I wouldn't be surprised if an adjustable gas block is in my future.

 

[sgreen3]

Thanks for the info fellas, but I ended up resurrecting the 300blk pistol build. Got it lined out today actually and put some reloads through it and have it working great. Very glad I took a look at the 300blk again. Although I do plan to build a 10.5" 5.56 upper to go along with it.

 

[LuckyOne]

And what length of barrel did you use for the 300 build?

 

[G3hkray]

I copied the spikes pistol but added their barking spider. The a2 put too much flame out the front.
I took it to tactical response and ran wolf with no problems and didn't clean it till I got home but I
did put some oil in the chamber before class each day