Slippers, myself, and a few other friends were out shooting today. We had my Colt M16 lower with Colt M4 receiver extension, carbine action spring, and H3 buffer. A Noveske N4 10.5" CHF mk18 CQBR upper typically lives on this lower. Slippers had his LMT MRP 10.5 upper with Gemtech suppressed bolt carrier and SiCo Saker 762. This upper/bolt carrier combo is unbelievably smooth. It feels like you are shooting a 22lr MG. We all had no issue making 2-5 round burst hits on torso sized steel at 100 yards with the fore end braced on barricade. This upper makes me want to install the Gemtech carrier in all my suppressed uppers. And my Noveske really needs a BRT reduced gas port.
And Dead Air Key-mo mount, which has yet to get stuck despite many hundreds of rounds of full auto between removals. 
[video=youtube_share;1SdWE5y-F3w]https://youtu.be/1SdWE5y-F3w[/video]
A little slow motion clip:
[video=youtube_share;d5eI8TswUFg]https://youtu.be/d5eI8TswUFg[/video]
Do like the Gemtech carrier better than say the LMT E-carrier because you’re running bursts and suppressed? I have an LMT-E carrier to run suppressed, but not in auto, though I considered the Gemtech. Curious as I am just starting to learn how the suppressor affects the operation rifles.
NC
Yes, I prefer the gemtech carrier. I have a couple LMT e-carriers, but on a 10.5 with a suppressor I can’t tell a difference between the e-carrier or a standard carrier. The recoil impulse is harsh, the cyclic rate is very high, and the gas-to-face is obnoxious. The gun also fouls up very quickly. I’ve tried both a carbine receiver extension with H3 and A5 extension with A5H3. The carbine extension with H3 wouldn’t reliably lock back on the last round unsuppressed once the gun was shot a bunch and dirty. I have tried various sprinco springs, but the heavier ones result in the muzzle dipping when the bolt closes due to the increased carrier velocity.
I use an A5H2 and colt rifle spring with the gemtech carrier and the gun can go 500+ rounds between cleaning (I’ve never let it go further, but it hasn’t ever malfunctioned in this configuration either), all suppressed, doesn’t get all gritty feeling when you operate the charging handle, has very little gas-to-face, and is extremely smooth. You can see in the videos that it barely moves, allowing us to land multiple hits in short bursts.
The suppressor you’re using will also have a big effect on performance. I’m using a 7.62 can, so it has less back pressure with 5.56. Previously I tried to use my specwar 556K, and even with the gemtech carrier it was much gassier and faster cycling.
I recently bought one of the Bootleg adjustable carriers and got to try it out for the first time today with my 11.5" BCM and saker 556. Going from the unsuppressed to suppressed settings with the can on was a drastic difference. No gas to the face (i’m a lefty) on suppressed settings, and recoil was much nicer. I would imagine the gemtech feels the same.
Slippers and Nate89, I appreciate the info. I test fired (indoors) the suppressor several months ago with a moderate rate of fire on a BCM 11.5 and it seemed to run ok. There were no cycle issues, the recoil impulse didn’t seem to be a problem and I wasn’t choking on gas. I have two different 11.5" uppers, a BCM and a build using the Sionics RGP barrel to run with an SF 556-212 suppressor. One lower is set up with a carbine RE/H3 buffer the other with an A5 RE/A5H2 or A5H4. Will watch for the issues you described.
Slippers, would you feel the Gemtech carrier was necessary if you weren’t running in auto?
NC
Yes. I am cursed with a very sensitive nose, though. I hate gassy rifles. One of the main advantages of the Gemtech carrier is that it reduces the cyclic rate. Even if you don’t run full-auto, the benefits of this are still important. Reduced lock time, fouling, and less wear.
Although this isn’t relevant to most people, the Bootleg carrier is not full-auto rated despite the same company also making the Gemtech SBC.
I was not aware the Bootleg Carrier is not FA rated. I understand why there is a price difference now.
Awesome videos guys.
How much does that SBR combo weigh?
Ok, I now understand the gas issue. I gave my SBR/suppressor a workout today. BCM ELW barrel and LMT-E carrier with PMC Bronze, GECO 223 Fed XM193, IMI M193 and IMI 77gr OTM. PMC bronze was a little gassy, same with Geco. The IMI 55gr and 77gr were pretty unbearable. I had to stop shooting a couple of times because of the gas to the face.
Sionics 11.5 RGP with NP3 carrier was about the same amount of “gassy-ness”, especially the IMI 556.
I have a LaRue 18" barrel with a FA phosphate carrier was gassy with BH 223 and obnoxious with 556.
I see a Gemtech adj carrier in my near future.
It’s definitely not a light gun between the MRP and medium/heavy profile barrel, and 22 oz of Saker 762 on the end. Total weight is over 9 lbs including Micro T2 and G33 magnifier, empty.
I pretty much wrote off the Gemtech BCG when it first came out, and probably expressed those feelings here. This has changed my attitude a bit. Surely, it’s not hard to imagine that I value the views of some over others. I place value on what you two express. I appreciate you guys sharing your experience.
I was pretty skeptical, too. And I’m not happy with some things about the carriers. The 308 version can’t fit an LMT MWS firing pin, for instance. The staking on the gas key on every carrier I have seen is messy, leaving large burrs. The gas key screws are YFS. Basically I replace the gas key and screws with Colt or BCM parts, and stake it with one of Ned’s tools.
As far as performance goes, it’s not a bandaid for a super overgassed gun, especially with short barrels. The gun needs to be reasonably gassed to begin with, and then the carrier works wonderfully. JoshNC’s 10.5 Noveske barrel is good example. It definitely helps a little, but the barrel is overgassed so the recoil is a bit harsher and the rate of fire is faster than my MRP. I have also used the Gemtech carrier on my BCM 11.5" and it runs well in that.
Gemtech has some cyclic rate data available that shows how the carrier is able to keep the rate of fire closer between suppressed and unsuppressed settings with longer barrels, while short barrels don’t see the same results (i.e. the Gemtech carrier can’t quite slow down the rate of fire as much when suppressed).
That’s good to know. My MOACKS doesn’t get much use, except when someone brings me an AR to look at.
Have you compared the Bootleg carrier key and screws to the Gemtech?
Not sure if asking me, but no. I won’t buy the bootleg because it’s not full auto rated, and that’s a requirement.
Slippers - are you noticing any excessive wear inside the upper receiver like others have reported? I would guess that the FA would accelerate any abnormal wear as well, if there is any.
Received the Gemtech BC last week. In tests at the range with a BCM 11.5" SBR and Noveske 10.5" SBR using a SICO Saker 5.56, the reduction of gas to the face was substantial. I could not determine if the recoil impulse was less than the standard BC. Using an H3 buffer and standard carbine recoil spring, I’d never had any previous issues with the buffer bottoming out in the buffer tube.
The gas key staking was OK on one screw and questionable on the other…noting that can’t be fixed with a new screw and moacks.
We’ll see how the Gemtech BC holds up for the long term…
Someone connected with Gemtech please persuade them to make a drop in BCG for our beloved LMT MWS weapon systems. They would sell one metric shit ton. Anybody running those guns with a can would sign up IMHO.
I gotta say, I want to grab one for my SBR’s to play with. A member was kind enough to loan me one but I still never took the plunge. This thread may have cost me dearly.
PB