New 10.5" AR pistol build

[KKing]

I swore off AR pistols after I built a 7.5" years ago due to only being able to place my cheek on the buffer tube and lack of stability therein, it just didn't get shot like my carbines. That was all before this Sig SB15 brace business...now we're talking. I've started with a blem upper and lower from Anderson Mfg., which have a surprisingly snug fit to one another. This won't be a "budget build", but it will be a budget conscious build. Anyway, as pictured I've got the lower together aside from the rear takedown pin due to waiting on my end plate to arrive. The LPK is from PSA and it came with the B5 grip and trigger guard, both of which I really like, for $49. Here in the next few days I'll have my barrel arriving, and I'll be able to post more info about the adjustable gas block and other parts I'll be running. As I said it won't blow anyone's mind, but I've never done a true build thread. There will be a couple of neat touches though. Battle Cock Tactical is going to stipple the grip and a couple of Emags for me, his work is just plain cool. This is gonna be just a fun range toy. The Sig brace warmed my heart back up to these pistols again Old 7.5" pistol I sold to a member on here I'll keep this thread updated as parts should pretty well come in weekly. I plan on having it finished at least by the first of August, if time and funds allow.

[Dustbuster]

Lookin good!! !!!


Sent from my iPhone using Tapatalk 2 of course it ate my spelling.

[KKing]

So, I'm terrible at keeping things updated as you can tell. Since the last post I've gotten in my barrel, gas block, keymod handguard, Sig brace, and a couple other small things. I'm using Kies adjustable gas block, which I don't think for the money can be beat. http://www.joeboboutfitters.com/Kies_CLAMP_ON_Adjustable_Low_Profile_Gas_Block_p/kies-adjgasblockclampon.htm It uses a tiny set screw to hold the gas tube in the gas block, which is an awesome touch. The only downside I see to it is it doesn't have a secondary brass set screw to lock in the gas adjustment once set like the more expensive brands like Seekins do. I'm thinking about either drilling and tapping a hole for one, or simply running red lock tite since I won't be running suppressed, once it's set I plan on leaving it. I picked up a barrel from strore.ar15.com. It's a 10.5" heavy barrel with a 1/9 twist that's nitrited inside and out. Got it to my front door for $130 shipped. It can't be the best barrel on the market for that kind of money, but for sub 50 yard work, it can't be too bad. The keymod rail is MI's SSK in 10.5". I've been hesitant to jump on the keymod wagon, this rail makes me glad I did. The Sig brace with KAK tube puts the LOP on this gun within 1/2" of what I normally run, which doesn't bother me since I'll stay nice and compact with the shorter barrel. I plan to take some detail photos and close up shots of everything this weekend, for now I've got everything together hand tight just for visual. I'm still missing a BCG and charging handle that'll come later this month. Disregard the pressure switch rail mount on the top rail, I've taken that off and I'll just be using the tailcap on the light

[Dustbuster]

Once you set the gas block adjustment that screw may not move much at all, I can't adjust unless I fire a few rounds to heat up the barrel then readjust.the carbon and crap act like Loctite after a while...


Sent from my iPhone using Tapatalk 2 of course it ate my spelling. Edited July 9, 2014 by Dustbuster

[Lumber_Jack]

I have that very same Kies adjustable block on my 16". I use blue loctite. It won't move unless you want to adjust it. I just count half turns from closed to the setting I want. Remove the screw completely, apply loctite, reinsert screw to close and open with appropriate number of half turns. Allow to dry.

[KKing]

[quote name="Dustbuster" post="1166942" timestamp="1404916747"]Once you set the gas block adjustment that screw may not move much at all, I can't adjust unless I fire a few rounds to heat up the barrel then readjust.the carbon and crap act like Loctite after a while[/quote] Awesome, thanks for the info

I have that very same Kies adjustable block on my 16". I use blue loctite. It won't move unless you want to adjust it. I just count half turns from closed to the setting I want. Remove the screw completely, apply loctite, reinsert screw to close and open with appropriate number of half turns. Allow to dry.

Very good to hear from someone who has that gas block. Looking on ARFCOM I didn't find very many reviews. Thanks for the advice. Honestly, for the shooting I do it's probably not worth drilling/tapping a hole. If this were a duty gun I would have just had to use the Seekins to begin with, ya know?

[Lumber_Jack]

Actually, I don't like the Seekins very much. I have one on my .300blk. The problem is the adjustment screw is on the reciever side, which makes it impossible to adjust with the rail on regardless of how large the holes are. If I were wanting to make adjustments for taking a suppressor on and off or ammo changes I'd go with a Syrac Ordnance Gen II or an SLR rifleworks. Both use spring retention inside the block to create clicks when you turn the screw. Both are over a $100 tho, so I'd have to determine a true need for field adjustments.

[KKing]

So I'm wondering, if I'm going to be running my gas as low as possible for operation, what's everyone's thoughts on a low mass BCG? I normally just run an M16 carrier and heavy buffer/spring, especially on anything shorter than a 16" but since it will only have *just* enough gas I thought maybe it would be fun to run a low mass carrier and see how light I can get the recoil. I typically try to dodge using a adjustable gas block by buying barrels from companies that I know drill theirs to the correct spec. so this is a little bit of new territory for me even though I've built quite a few ETA: better picture. As you can see I still need several things on and in the upper. I'm also sad I can't reach my gas adjustment screw with the rail on. Ah well...

Edited July 10, 2014 by KKing

[Oh Shoot]

So I'm wondering, if I'm going to be running my gas as low as possible for operation, what's everyone's thoughts on a low mass BCG? I normally just run an M16 carrier and heavy buffer/spring, especially on anything shorter than a 16" but since it will only have *just* enough gas I thought maybe it would be fun to run a low mass carrier and see how light I can get the recoil. ....

 

My understanding is that "recoil" can only be reduced by a component that absorbs it or dissipates it.  Except for a spring loaded stock or ported barrel, that would come down to more resistance from something internal in the firearm -- and in the case of the AR design that would be heavier BCG, buffer, and/or buffer spring.

 

Certainly, the least gas you allow to backflow for successful operation will reduce "snappiness", and I guess to some extent "recoil", but I've always failed to see how lighter internals that receive the initial force of x volume of gas could be more effective than heavier ones in ameliorating that x volume before you feel it on ass end.

 

Seems to me the optimal tweak would be combination of the least gassing and most resistance to it that still maintains reliable function.

 

Btw, here's one recent failed experiment with light buffering attempt to do same as you postulate:

 

http://www.tngunowners.com/forums/topic/79789-ultra-light-buffer/

 

 

 

- OS

Edited July 10, 2014 by Oh Shoot

[Oh Shoot]

Btw, as addendum to above post, and especially since I don't reload,  I've never delved into trying to precisely tweak any of my firearms for optimal performance. It's enough for me that they run reliably with any round I can find to stick in them. :)
 
Anyway, I do have two 10.5" AR pistols. First one has J&T 1:9 barrel (whoever actually makes it anyway), and second one has FN 1:8. No idea if ports are in spec or too big, as both came with A2 fixed sight base blocks. All I can tell you is that both run everything from the weakest .223 I know of (Federal bulk) to NATO 5.56 flawlessly.
 
They do both have M16 carriers in them. They both ran fine with standard carbine 3 oz buffer and standard spring. I did get H2 buffers to put in both, thinking there might be a reduction in "snap" of the operation (although "recoil" is just not an issue with 5.56 to me period, otherwise couldn't hold one alongside cheek and let it rip).
 
The heavier buffers increased ejection angle slightly, maybe like to 4:15 instead of 4:00, but seems rather subjective as to whether I can "feel" any diff. Been meaning to take both buffers with me some time and swap back and forth to see if can really tell.
 
The first one started simple, but evolved into something like yours. Here shown in its "firearm" configuration.
 

 
And not too long ago, even though I thought I was through with AR assemblage forever, couldn't resist picking up a Knoxville branded lower from Predator, "just because", and then after rearranging that into other rifles found I had most everything laying around for another AR except upper, and PSA had their 10.5 build with the fine FN barrel on sale, so well, you know. So I wound up with another simple one that is much like the first one started. :)
 

 

And yeah, I'm gonna leave the second one just the way it is, I promise. :) May keep it in the car -- sure it would hurt to have it stolen, but not as much as the first one, as don't have as much in it. Plus it fits my uber discreet high tech covert carry bag, and the original one doesn't any more. :)

 

- OS

Edited July 11, 2014 by Oh Shoot

[KKing]

OS, that makes sense. I'm just going to try and run a carbine spring and buffer on this one instead of the h2 or 3 buffers I've ran on some before, that's the main reason for the adjustable block. I guess if I was really stuck on a flatter shooting weapon I could run a muzzle brake like the fortis RED I run on a 16" gun, but the sane portion of my brain knows how inherently loud short barrels are and how much I value my hearing. I think I really used the wrong term to describe my ultimate goal. I used the word "recoil" but like you stated, even with severely overgassed guns 5.56 has no real recoil. I guess I'd like to try and replicate how soft shooting some of my longer barrels are. Usually when tuning my AR's I just make sure they will lock back and run with the weakest ammo in my stash, which for this one may likely be a steady diet of steel case since it won't cost much to replace this barrel if/ when I can shoot enough bimetal bullets to wear it out. As a side note, OS I'd like for you to shoot a couple of my guns with muzzle brakes that have been tuned to have zero recoil and make follow up shots very, very easy and see of you can tell the difference. Not that mine would be superior, just to see what you think of them. Those guns won't reliably cycle steel cased ammo though, so there is a downside to those I'm speaking of. After I felt my first truly properly (subjective term) tuned AR, I knew I had to make at least some of mine feel the same. Now on every new build I find myself sort-of chasing that "first high" feeling I can definitely tell one thing when I actually assembled and snugged everything up tonight I realized I'm going to have to invest in some keymod panels to protect my sausage fingers. The I.D. on this rail is tiny and your fingers are very close to the gas block. I suspect things will get quite toasty in that area Edited July 11, 2014 by KKing