View Full Version : Gemtech suppressed bolt carrier, LMT MRP 10.5, SiCo Saker 762 on M16 lower - amazing
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. :)
https://youtu.be/1SdWE5y-F3w
A little slow motion clip:
https://youtu.be/d5eI8TswUFg
nightchief
06-13-17, 04:30
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
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.
nightchief
06-13-17, 19:10
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
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.
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?
nightchief
06-15-17, 17:52
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.
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.
Awesome videos guys.
How much does that SBR combo weigh?
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 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).
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.
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?
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.
Singlestack Wonder
07-07-17, 11:41
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...
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).
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
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
There's a thread on sh where someone used the gemtech 308 carrier with a JP high pressure bolt in their MWS. The JP bolt includes their own firing pin.
There's a thread on sh where someone used the gemtech 308 carrier with a JP high pressure bolt in their MWS. The JP bolt includes their own firing pin.
I read that thread but found it to be more confusing than that. I appreciate you simplifying that thread. I thought he bought 3 pieces of kit to make it run.
PB
Too bad the 7.62 sbc is pretty scarce. Plus the combined cost of the carrier and jp bolt is $450+. :bad:
Too bad the 7.62 sbc is pretty scarce. Plus the combined cost of the carrier and jp bolt is $450+. :bad:
Yea, your approaching custom new barrel cost.
PB
Yea, your approaching custom new barrel cost.
PB
Or spending a hair more and buying an ACC instead of an MWS depending on the deal.
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).
I was very skeptical until you purchased one and we shot it. It is a great addition to a suppressed AR. And to your point about it not being a bandaid for overgassed uppers, I think my two overgassed mk18 uppers demonstrate this rather well. Though they are confounded by their use of 5.56 cans vs. your 762 can.
Which reminds me, I still need to order some BRT ports for those two uppers. And a GT SBC.
Singlestack Wonder
07-19-17, 10:38
My first use of the Gemtech bolt carrier was limited to testing the premise of whether or not it did an adequate job of diminishing gas to the face. As previously stated, it did that well over the course of firing 20 rounds. Yesterday I went to the range to run drills and shot 200 rounds over the course of 30 minutes. I run a Saker 5.56 on a BCM 11.5" SBR. I noticed that the handguard and upper receiver heated up exponentially more with the Gemtech bolt carrier vs. the standard BCM. A glove was required to continue. The noise at the ear seemed louder as well.
In the past, running the SBR with the Saker 5.56 and BCM bcg, while the handguard was warm, I never had to utilize a glove during sessions firing 300-400 rounds.
Has anyone else experienced the additional heat using the Gemtech bolt carrier?
My first use of the Gemtech bolt carrier was limited to testing the premise of whether or not it did an adequate job of diminishing gas to the face. As previously stated, it did that well over the course of firing 20 rounds. Yesterday I went to the range to run drills and shot 200 rounds over the course of 30 minutes. I run a Saker 5.56 on a BCM 11.5" SBR. I noticed that the handguard and upper receiver heated up exponentially more with the Gemtech bolt carrier vs. the standard BCM. A glove was required to continue. The noise at the ear seemed louder as well.
In the past, running the SBR with the Saker 5.56 and BCM bcg, while the handguard was warm, I never had to utilize a glove during sessions firing 300-400 rounds.
Has anyone else experienced the additional heat using the Gemtech bolt carrier?
I doubt the carrier has any bearing on the handguard heat. Suppressed guns get hot, and the carrier isn't trapping anything or contributing to additional heat at the gas block.
Singlestack Wonder
07-19-17, 13:27
Just got back from the range. fired 200 rounds over the course of 30 minutes with the BCM BCG in the same SBR. As before, handguard was warm but never so hot as to require a glove.
Is it possible that by venting gas at the supressed bcg allows for more hot gas to flow to the rear of the rifle, vs. the restricted flow with the normal bcg forcing more gas out the muzzle end?
Just got back from the range. fired 200 rounds over the course of 30 minutes with the BCM BCG in the same SBR. As before, handguard was warm but never so hot as to require a glove.
Is it possible that by venting gas at the supressed bcg allows for more hot gas to flow to the rear of the rifle, vs. the restricted flow with the normal bcg forcing more gas out the muzzle end?
Hmm. I take back what I said about the carrier trapping something. The delayed unlocking that reduces the gas-to-face also means more gas is vented through the suppressor and out the front. More heat in the suppressor, which in turn means more heat in the barrel, and leads to a hotter handguard as the heat radiates from the barrel.
But, if you think about it, this is how it should be anyways. If you have excessive back pressure the gun isn't running optimally to begin with.
Singlestack Wonder
07-19-17, 16:10
Hmm. I take back what I said about the carrier trapping something. The delayed unlocking that reduces the gas-to-face also means more gas is vented through the suppressor and out the front. More heat in the suppressor, which in turn means more heat in the barrel, and leads to a hotter handguard as the heat radiates from the barrel.
But, if you think about it, this is how it should be anyways. If you have excessive back pressure the gun isn't running optimally to begin with.
SBR runs properly without the Gemtech bc. With the H3 buffer, the rear of the buffer shows zero contact with the end of the buffer tube and the recoil difference between the Gemtech and BCM bc's is non-detectable (at least to me on the 11.5"). I would occasionally get gas to the face when shooting 6 or more rounds in quick succession with the standard bc.. I wanted to try to eliminate the occasional gas to face with the Gemtech bc. However, the occasional gas to the face wasn't a target engagement stopper, just a minor irritation every now and then. I'd rather live with that and be able to handle the weapon all day without a glove vs. the overheated situation with the Gemtech bc. YMMV
Doesn't the Gemtech SBC work by venting gas from the piston chamber?
If so, that results in lower piston pressures but more gas flow down the tube, which carries more heat with it.
This could explain the extra heat in the hand guard area.
Singlestack Wonder
07-19-17, 20:20
Doesn't the Gemtech SBC work by venting gas from the piston chamber?
If so, that results in lower piston pressures but more gas flow down the tube, which carries more heat with it.
This could explain the extra heat in the hand guard area.
That's my theory as well. Noise at the right ear is much more as well.
Does the gas tube alone really have enough thermal mass to radiate a large amount of heat for the handguard to absorb it, and be significantly noticeable over your firing schedule? Honest question. It's not like gas flows through the tube for very long (although slightly longer with a suppressor on the end). It certainly gets hot enough to burn you, but I'm curious if it can contribute that much heat compared to the barrel.
Singlestack Wonder
07-19-17, 21:11
The gas remaining in the barrel longer due the the increased unlock cycle time, could contribute significantly to the heat issue.
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