I am not sure. It looks like its a bit backward from the gas res I can see on the barrel. I may have to do a slow mo video to find out exactly . I am going crazy waiting on my new order from Syrac. Syrac Ordnance if you reading this. When will the pistol pistons ship? I have an approved SBR that dying to be built right now. I have most of the part in but its missing a piston system

I plan on doing a 2A Armament BL build with their 15" BL Rail. ID is 1.3" like the BCM KMR. I would love to use this piston kit.

Does anyone know if it'll fit?

Cheers
Shannon

The horizontal gap under the top rail is smaller/thinner than the gas block of the syrac piston. :(

Thanks for the heads up .....Man....that sux

Maybe when the .625 comes out it will squeak in there
Cheers
Shannon

I keep seeing things on here that say this system won't work with the KMR but I've also seen post of pictures with this system under a KMR. I want to Build a 300 Blackout SBR with this but can't figure out if it'll work or not with the KMR.

I don't know about the kmr, I was referring to the 2A Armament Balios Light handguard

It will work with the KMR. Its a close fit but it does work.

Any word on if this will fit under an NSR or a Geissele MK1 MOD1?

I'm surprised no one has reported back on the NSR yet.

I have a kit on order and can test it under an existing NSR I have but if anyone else has already tried it go ahead and chime in please.

Any update on a .308 version? Have a build ready for a kit! (Aero M5, BA 18" rifle length barrel. LMT DMR stock)

When will we see a low mass carrier avaliable?

After the NiBX version if at all would be my GUESS.

I was told by Syrac that the NiBX version is still a few months out.

The good news is that Midway USA shows to have shipped my Syrac Piston kit yesterday.

Bad news for Noveske fans.

I tried test fitting my Syrac gas block yesterday to both my NSR and my Noveske quad rail and it did not clear either of them.

It was very close on the NSR and could possibly be made to fit with a little work.  The top of the gas block contacts the anti-rotational channel at the top of the rail.  If I had removed my NSR rail covers and taped it on with a rubber mallet it might have worked but the gas block would be contacting the rail.  I didn't try this because my NSR is 13.5" and the Syrac kit I have is pistol length.  I just tried the NSR as a test fit.

What is even more upsetting to me is that the Syrac kit does not clear the Noveske branded SWS quad rail that I was planning to use on this build. The top of the gas block fits the top channel of the rail like a glove.  It is almost as if they used the same jig to cut them.  The problem is the bottom of the clamp on gas block.  The screws protrude too far out to clear the rounded bottom of the rail.  I removed the three screws and can then slide the rail over the gas block about 3 inches but then it hits where the picatinny rails begin at the back of the rail because there is a slightly raised ledge there inside the rail.

Removing some material from the bottom of the gas block and using different screws with smaller heads would probably get it done but the rail would still be riding the gas block at the top.

Does anyone know if this contact would effect barrel harmonics/accuracy?

I don't know what to do now.  This 10.5" 300blk is going to be suppressed 95% of the time and I really wanted to try a piston system on it.  The Syrac system really does seem well designed but the clamp on gas block is a real disappointment.  I have Syrac's adjustable set screw gas block on my 16" Noveske and it has tons of room to spare.  Had they offered a set screw version of the gas block in the piston kit it would have fit under both of these rails no problem.

I am going to put everything in the vice this weekend and really do some massaging (and maybe some filing/grinding) and report back but I still have concerns about the gas block contacting the rail and if that will effect the accuracy?


Edit- After a hard push I was able to slide the NSR over the Syrac piston gas block.  I did not test the op rod or attach the rail to the barrel nut but I think I can make it work.  The gas block definitely contacts the inside of the rail on the top and bottom but since I am building a short barrel 300blk I am not too concerned with what minor effect if any this might have on long range accuracy.  Now I just need to find a 9" NSR and I will put this thing together.

I had a similar gas block shoulder and port  "out of spec"  issue  with my DD 14.5 lightweight .625 inch middy a few years ago. My AA block lined up with the gas port and the shoulder perfectly. But the whole shoulder and gas port were indeed closer to the upper receiver than spec. As a result the piston op rod ended up being too LONG. The bolt carrier would actually hammer the entire gas block forward after 2 rounds, thus stopping the gas flow. The gun would NOT cycle at all when this would happen.

I messed with it for a few days until I did the only logical thing. The solution in my particular case was easy. I did not want to modify my AA equipment. but In the end I had to. Modifying the DD barrel was pretty much out of the question.

The permanent fix took about one minute. I faced the end of the AA  piston op rod on a slow speed belt sander as to not change the temper of the steel. I lost the Melonite on the end (striking face) but that was of zero consequence. Overall, I shortened the piston op rod about .15" which gave me perfect operation and achieved AA's specified clearance (free play) in the piston system.  The clearance was the equivalent width of a business card as I recall....between the piston cup and the gas block body.

I had a spare op rod that I could have used if I ever wanted to switch it to another upper or get rid of just the DD barrel. But I never needed the spare. I I ended up keeping the gun in exactly the same modified configuration. It is still  working flawlessly.

One issue might be having to shorten the Syrac op rod for the same reason. It would be much more involved than one minute on a belt sander because of the rounded, contoured  ball end that needs to mate perfectly with the bolt carrier key. I was really pissed with DD for a while. I got over it. I got lucky that my fix was so easy in the end.

My next build will be a 300 Blackout SBR with the new Syrac piston. Wow, it embodies ALL the things that was lacking on the AA system.

Jason is only about 8 months overdue on the lightweight carrier...LOL. Dont even bring up the .308 carrier! Oh, well. No worries. I think I will braze on a rod permanently so I can adjust my gas with out that stupid special tool. Like I wont loose that!  Gas adjustments should be tooless IMO. I cam modify the system to my needs. No worries.
The ONLY gripe I have is that I am unsure if the spring is Chrome Silicon or not. Piano wire simply does not cut it. I do not know how I will be able to spec a custom Chrome Silicon spring.

I replace as many springs as possible on all my AR15 builds with Chrome Silicon. I do not believe in music wire springs in dynamic moving parts! Music wire springs have no place on an AR15 ecxept for the relatively seldom cycled or used springs.

For all my piston builds I used to use only Samson Evolution rails. I KNOW they will fit. They even have a 4" addition to use say on a mid length gas system to extend your rail to rifle lenght and still be able to access an AA piston by hand. I am not positive, but I think the Evo rail will not actually cover the Syrac blcok, but it has cut out and options with a gas piston system firmly in mind when Samson developed these rails FOR Adams Arms. I love Samson Evo. For my purposes I found something better.

I found a hand guard that will totally clear and COVER a Syrac. It will clear and COVER a large 7.62 suppressor too. That gives you options! Lots of them.

The BEST rails IMO for a piston build (and suppressed builds) are AP Customs Gen 1 or Gen 2 hand guards.

Why people are scared/frightened/terrified of carbon fiber hand guards is a mystery to me. I would fo to war with a Gen 2 version..also with the RHINO version.  I dont think the super thick Rhino version will fit over the Syrac block. Its diameter is LESS than 2". The Gen1 and Gen 2 have a FULL 2" round inner diameter. NO channel is present or needed.

You need a full 2" diameter hand guard like the AP Customs Gen1 and Gen 2 to clear a Syrac gas block. Look at the measurement. From center to TOP, the distance of the block  is 1.9". So the fit is tight, but NOT touching.  . You have a little over .1" inches of clearance. It does not touch and WILL not touch!

 AP Customs is G2G. You can club some one with this set up and not break it. These things are ultra light and uber strong. They handle intense heat (mag dumps) waay better than any alloy. Think about it. Look at all the motorcycles with Carbon Fiber  mufflers! CF COOLS to the touch faster than anything. It is not heat proof. Your hand can actually get hot. But it handles the whole situation of mag dumps better than any thing. Use a light weight fold up vert grip like I do. AP customs is G2G for full auto or bump fire.

I am telling you. Thousands of people are missing out on one the best set ups available. Many thousands like me own one.

Every body has their pet hand guard that they think they can not live with out. Just give in. SELL it...or keep it for another build.

I have a RIFLE length gas system that I COVER with a Gen1 15" AP customs hand guard. Weight of mine? 6.5oz WITH the attachment trunnion!
I am going for minimalist. Most users prefer the Gen 2 with a top rail. Remember. If you order an AP customs with NO top rail you are kind of screwed if you want to add one later. The top rail of AP is much higher than any other. They only sell the rail attached to one of their hand guards. Be aware of this. They do mention this..sort of. It is not all that clear on their website. That is why I mention this fact.

If you get a top railed AP Customs (or not) the rest of the hand guard is wide open to attach rail sections virtually anywhere on the sides and bottoms. You get the option of 45 degree off-set too! It is a VERY versatile and sturdy set up that WILL clear the Syrac. You can use lightweight Magpul poly rails OR alloy or steel rails. Only the Rhino has keymod or M-Loc options. Not a deal breaker for the Gen 1 and Gen 2 which only offer conventional mounting. Mount your rail sections wisely and 99% of the time you will never change your set up.

I am going to have to disagree because the math does not add up.

The AP Custom CF hand guards have an inner diameter of 1.875" (Mine measures this same value.)
This means the radius (or centerline to inner diameter) is 0.9375"

The distance from the centerline of the Syrac piston kit is 0.986" (directly from their website)

This means there is a 0.0485" interference between the top of the block and the hand guard.  

Now there is a chance you might have the mounting hardware torqued to the barrel nut slightly off center which would result in your hand guard and top rail being a little higher giving you the clearance you describe....

The spring used in the piston is your basic magazine release/catch spring.  I think Jason is a genius for using a spring that is so easily replaceable. So far I have over 1000 rounds through my first build and its still running great. I can see a little compression from the heat and action on the spring but its a mag release spring I could change it anytime I wanted

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over 60 days