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Birth of a suppressed SBR, pic heavy

3K views 6 replies 4 participants last post by  arinvolvo 
#1 ·
aka: billets, pistons, suppressors and paint, a love story.

Please note that many of these pictures appear in other threads, in other parts of this forum. I am attempting to put them all in a single place, and chronicle the path in which this particular sbr took into existence.

I've been toying with the idea of suppressing an AR for years. Being a lefty, every time I ACTUALLY shot a suppressed AR, reminded me why I hadn't done it sooner. The violent blast of hot gas and powder out of the ejection port at least FEELS like it has the potential to blind, if without eyepro.

With the advent of several new piston retrofits available on the market, I again became interested in suppressed shooting. In fact, I had placed and order, and paid for a 5.56 suppressor 2 days prior to SHOT 2008, with the plan of researching the piston system with which to run it, at the show.

Prior to all of this, I had run across a small outfit, producing billet AR lower receivers. I asked about them on several forums, no one had heard of them, or had ever seen one. I decided that if I wanted to touch one of these receivers, I would have to buy one. I received a double digit serial (obviously these guys were newer than I even thought)...and was quite impressed. I posted pics and a review of the lower on several sites...



I then decided that I liked the lower SO much, I might as well SBR it. The company offered to do my SBR engraving for free, as a "thank you" for all of the pics I had posted around the net.



Later at SHOT show, in talking to Mr Larue, I learned that my pictures had inspired him to contact the company, and from there, the Larue billet lowers were born.

I decided that I wanted a very similar sbr setup to my current carbine setup. Turns out I was going to have little choice, as funds required me to strip my current carbine, in order to dress my new sbr build (shut up sneaky). My current carbine was completely gutted of its juicy bits, including the requisite unpinning of the flash hider in order to salvage my Larue rail.

RIP SOLDIER


I ordered a 10.5 inch LMT upper, which was test fitted to the sbr'd lower.



I then fitted it with my salvaged Larue rail.



After that, I had enough to prep and paint the rig with a custom mixed Norrell's moly resin. I mixed about a capful of flat black with their flat dark earth, to darken it up, and more closely match the magpul FDE parts I already had.



I then assembled the rifle in a test configuration with most of the parts taken from my sacrificial carbine.



The upper was then sent to PWS for a piston retrofit. Hilarity and "Not for rectal insertion" lore ensued.

 
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#2 ·
At this point, my sbr entered a stage of constant change. I came to the realization that the Pentagonlight/Larue mount combo did not work with the short bbl of the sbr. The side blast produced by the PWS compensator not only blackened the glass of the Pentagonlight, but also caused enough concussion to dislodge the retaining ring, and allow the entire bulb assembly to fall out, onto the ground, while shooting. I was in need of a more compact, more robust solution.





A pistol-style light was stolen from my sidearm, and run, along with the Larue FUG grip for a while, until I was satisfied enough to order a dedicated pistol style light for the rig. The Insight Procyon was added, and the FUG was moved forward.



At this point also, my suppressor had arrived at my dealer, but was still waiting for paperwork. I retrieved the QD mount and installed it. This is when I realized that I had made a planning error worthy of the "FAIL" thread. The QD collar of my flash hider did not allow expedient service of the piston assembly. The flash hider must be removed completely to allow the piston components to slide out the front of the PWS gasblock.



The fact that the piston neither NEEDS to, and probably SHOULDN'T be field stripped, has allowed me to, thus far, overlook this little snafu, and drive on. Couple this with the fact that I simply cannot afford another suppressor (next will be a GT, I promise Kel), means that this setup will have to do for now.

I recently acquired a second hand gen1 redimag, and after 15 minutes or so with a dremel, I was able to fit it to the more robust dimensions of the billet magwell. While this item adds literally POUNDS of weight, the more I have been training with it, the more I cannot believe that I went so long without one. The gen1 action lends itself well to lefty operation, and every time I use it, I get faster and more confident with the system.



Recently, I have been running the sbr without the forward grip. I have found that it makes reaching the light toggles more difficult, and complicated my transition to magwell hold required for lefty mag change more difficult. My 3x magnifier set up has also been seeing less and less action as lately I cannot justify the added weight. I used it at the last 3 gun match, and found myself making slower, albeit more accurate shots. I realized that the precision in which I could see the target made me hunt for the "perfect" sight picture, rather than pulling the trigger on the "good enough" sight picture. I think it will be seeing less and less time mounted on top of this sbr.

My suppressor, after a long wait, has been the final addition to this rig. The piston system, while not COMLETELY eliminating gas blow back, attenuates it enough that it is no longer "painful" to shoot suppressed. It also keeps the entire system SUPRISINGLY clean. I have not ONCE cleaned this gun since it was originally assembled into a shootable condition. The bolt and carrier have received additional oil only. At this point, my total round count through this system is approximately 1650 rounds (easy to keep track of, as this is my only AR, and only firearm in this caliber), and today at the range, I had my first stoppage. A stuck WOLF steel case, which the extractor tore half the rim from. The case had to be tapped out with a rod, and I ran about 4 more trouble free mags following the stoppage. At this point, I assume it is finally time to give the chamber its maiden scrubbing.

Even though this stoppage was a "killer" as stoppages go, I can only blame my purposeful negligence. I have endeavored to run this system to its limits, dirty, dry, hot, suppressed and with garbage ammo, and I am pleased with my results thusfar. I am happy to report that the LMT 10.5 bbl holds impressive 50 yard groups, and the suppressor has shown only a VERY small POI shift.

I am by no means FINISHED testing this rifle, but from here on out, it will be receiving regular cleaning and maintenance……in other words, I am finished ABUSING this rifle. Any further abuse will be in the form of courses designed to push man and machine to their limits, and at this point I am at least confident in the machine part.

Thanks for listening.



 
#7 ·
ok. been messing with the light position. the 12 o clock position has a LOT of advantages. the light can be activated equally easy from dominant or non dominant hand shooting. It keeps the light and subsequently the paddle switches more in line with the body of the carbine, reducing potential snags, and unwanted light activation. allows me to use my forward grip again, in my preferred grip, with the grip set forward like i like, and still easily activate the light either momentary or constant on.

another pro, keeps my light from being covered when shooting from the side of cover.

ok, CONS.

1. i am unable to mount to my gillion degree piston gas block, so both the light and the FSB are pushed back onto the FF rail...thus decreasing my iron sight radius. small con, not a deal breaker.

2. putting the fug back on is again adding weight to the front of the gun, which is already horribly front heavy. whatever, ill work out more, drive on.

The hand position in the pic looks uncomfortable. You are going to have to take my word that it feels and shoots right.



 
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