Armory Sponsor
Posted: 8/13/2015 8:29:14 PM EDT
|
Just got an email on this. Adjustable bolt carrier that has a switch you can change from unsuppressed to suppressed. Interesting concept.
stupid tablet won't let me hotlink http://www.gem-tech.com/store/pc/GEMTECH-5-56-Suppressed-Bolt-Carrier-55p1149.htm |
|
I've shot one a few times, it seemed to have a little less blow back. The tolerances on the one we use are tight, so it took a mag or two for it to really smooth out. I'm not a great blowback judge, as I'm not really sensitive to it at all...
I ran a M16 with 60 round mags, the Gemtech carrier, and a standard charging handle. About 30 rounds in I got "the smell" and a little gas in the face, but nothing that made me tear up or consider letting off the trigger. I was pretty sure that the cyclic rate was lower than I remembered an M16 being, and couldn't figure out why. I passed it off as shooting the select fire Glock before it but on the drive home realized that perhaps the bolt carrier was slowing it down some. I'll need to do more testing and figure out if it was just me that day, or if it did in fact slow it down a bit. |
|
Quoted:
Too bad the adjustment is on the wrong side 
For that amount of cash I'd just buy the adjustable gas key from RCA. I don't see the location of the adjustment as a problem, but I understand if some people don't want to bother with pushing the takedown pin, swinging the receivers open, and pulling the BCG out to switch the setting. However, IMO, the adjustable gas keys aren't even really comparable in functionality. This BCG gives you defined suppressed and unsuppressed settings, while the gas keys have no defined settings. They're good if you plan to set it once and forget it (to tame down an overgassed configuration), but for changing between suppressed and non this BCG would work better in concept. |
|
I put one of these SBCs in a legacy KAC SR-15 that had some over-gassing issues suppressed and it appears to of solved it for the most part. In the past just switching from the standard buffer to an H or H2 did not solve the very week ejection and nearly 12:15-12:30 ejection patterns I was getting shooting this SR-15 suppressed. Occasionally I would even get stovepipes or double feeds when shooting suppressed.
When I put the SBC in with the standard KAC buffer there was not much of a difference, but when I combined the SBC and the "H" buffer then this rifle finally had a consistent ejection at 2:45-3. So it appears to kinda work. I was expecting better results, but I am still looking forward to trying the 762 version in my LMT 308 which is very over-gassed even with one of slash's XH buffers. |
|
Quoted:
I put one of these SBCs in a legacy KAC SR-15 that had some over-gassing issues suppressed and it appears to of solved it for the most part. In the past just switching from the standard buffer to an H or H2 did not solve the very week ejection and nearly 12:15-12:30 ejection patterns I was getting shooting this SR-15 suppressed. Occasionally I would even get stovepipes or double feeds when shooting suppressed. When I put the SBC in with the standard KAC buffer there was not much of a difference, but when I combined the SBC and the "H" buffer then this rifle finally had a consistent ejection at 2:45-3. So it appears to kinda work. I was expecting better results, but I am still looking forward to trying the 762 version in my LMT 308 which is very over-gassed even with one of slash's XH buffers. What did it do when you took the suppressor off and switched the BCG back to the unsuppressed setting? |
|
Quoted:
What did it do when you took the suppressor off and switched the BCG back to the unsuppressed setting? Quoted:
Quoted:
I put one of these SBCs in a legacy KAC SR-15 that had some over-gassing issues suppressed and it appears to of solved it for the most part. In the past just switching from the standard buffer to an H or H2 did not solve the very week ejection and nearly 12:15-12:30 ejection patterns I was getting shooting this SR-15 suppressed. Occasionally I would even get stovepipes or double feeds when shooting suppressed. When I put the SBC in with the standard KAC buffer there was not much of a difference, but when I combined the SBC and the "H" buffer then this rifle finally had a consistent ejection at 2:45-3. So it appears to kinda work. I was expecting better results, but I am still looking forward to trying the 762 version in my LMT 308 which is very over-gassed even with one of slash's XH buffers. What did it do when you took the suppressor off and switched the BCG back to the unsuppressed setting? Never tried it unsuppressed or in the unsuppressed setting, sorry. |
| Well, I have one of these on the way. Once I get some rounds through it I'll give my impressions in case anybody is interested. I'll be mainly trying it out in my LMT MRP uppers as it may be the best solution for selectable gas feed (for suppressed and unsuppressed use) on those, but will probably try it in 'standard' uppers also. |
|
Ok, I had a chance to try out the Gemtech carrier. I see a lot of confusion about what the purpose of this carrier is, with many people comparing it to set screw adjustable gas blocks and adjustable gas keys. That's apples to oranges folks. The Gemtech carrier is meant to allow you to switch back and forth between suppressed and unsuppressed on a gun that is already gassed properly unsuppressed. If the gun is overgassed to start with this carrier is not going to allow you to fine tune the gas feed down to where you want it, and that's ok because that isn't the purpose of it. I write this first because you can't knock a product for not doing [something] when it wasn't designed to do that [something] to start with.
All that said, the carrier does what it's supposed to. I tried it on a couple different guns that function well unsuppressed on an H2 buffer and standard carbine spring. With the carrier set for suppressed and the can on, it functions about the same as with the carrier set for unsuppressed and the can off. Will the turn down in gas be perfect in all setups? No, there are way too many variables to get it perfect for every combination. But I was really happy with the way the guns were functioning suppressed using this carrier. Recoil feels about the same as unsuppressed, ejection is pretty close to the same, and there is very little blowback into the receivers. I'll continue to use the carrier and see how it goes but I don't expect any issues based on what I've seen so far. By the way, I also tried shooting with the carrier set for suppressed and no suppressor on the gun. In that case it did not reset the hammer or pick up another round off the mag. I mention this because it kind of illustrates the substantial difference in gas feed between the two settings. Some people have already mentioned that they don't like the adjustment being on the side opposite the ejection port, meaning there is no way to adjust it without removing the BCG from the upper. Well, that is true that you have to remove it to adjust it. But, I think it was a necessary part of the design. You see, this carrier has only one moving part, which is also the only additional part in the carrier as compared to a standard carrier. The settings are 180 degrees apart, and there is no detent to keep the valve set in either position. However, the way the valve/adjuster is designed, it can't rotate when the BCG is in the upper. Maybe I'm wrong, but I bet the one extra part thing was a design goal and in order to make sure it doesn't inadvertently move it has to be keyed to the upper. That being the case, it would have to be removed to change the setting anyway, so having the slot for changing settings on the ejection side wouldn't help anything really. I personally don't mind the fact that the carrier must be removed to change settings. Sure, it would be nice to have an external adjustment but that would really just be a nice to have feature and I wouldn't want to complicate the design with detents or more parts to get that. Anyway, the adjustment moved easily before and after firing about 150 rounds with the carrier installed. I do have two complaints about the Gemtech carrier. First, I don't like the "staking" on the gas key screws as I don't believe it's doing anything useful in terms of securing the screws. That doesn't necessarily mean the screws are going to come loose (and there are quality carriers without any gas key staking), but if they're going to do staking I'd rather see it done better. I'd also like to find out if Gemtech is using sealant between the key and carrier and threadlocker on the screws. If so, the staking is less of a concern. The second thing I guess I can complain about is the price. I got mine for about $200 and the MSRP is $249, which is a bit steep. I'm not aware of any other choice for carriers with this type of adjustment right now though, so you gotta pay to play. And Gemtech has a patent pending on this but I don't know what it entails or what it means regarding the possibility of other switchable carriers coming to market. An alternative that has been suggested is to buy two regular BCG's and an adjustable gas key to install on one of them. Then you can tune the one with the adjustable key for suppressed use only and just pop in whichever one you need. Not a bad idea but I'm not a fan of set screw adjustments for some applications and it also requires carrying the second BCG around with the gun. I really like that the Gemtech carrier is a self contained solution, though the value of that is a matter of personal preference and need. My primary interest in the carrier was for use in my LMT MRP uppers which have limited options when it comes to *switchable* gas feed for suppressed use, and for those uppers I think this is a really good solution. Really though, this carrier is probably a good drop in solution to get switchable gas feed for suppressed use in standard uppers since it doesn't require any wrenching and it's easily reversible or moved to a different upper. I'll certainly keep using mine and may end up getting another one or two down the road. You can see the gas key staking, the valve/adjuster, and the patent pending marking here: 
Here is the valve/adjuster removed. Just turn it halfway and it slides right out the left side of the carrier: 
Very happy to have this carrier as an option for my MRP uppers: 
|
Armory Sponsor