These days, there are all sorts of products and gadgets out there to help deal with shooting suppressed (technically over gassing). Adjustable gas BLOCKS ("AGB"), adjustable carriers, the WAR upper, even adjustable gas keys to replace the standard version.
To me, none of these solutions are really ideal. Most of them involve the addition of small set screws, detents, etc that quite frankly, I just don't trust. Sure, they work. But adjustable gas blocks started in the competitive world and have been adopted by the casual shooter. Adjustable carriers and gas keys came along as a drop in solution for folks that didn't want to screw around with the gas block. Or feasibly, something you could install and adjust without disassembling the upper.
Adjustable parts exist primarily for one reason. Too damn many companies are producing barrels with huge gas ports. That's fine if you're shooting unsuppressed and like to shoot weak steel case ammo. However, introduce full power ammo and a suppressor and you may have functional issues or the dreaded "gas face".
Regarding the use of adjustable parts, one of the things I've always felt was that while they work, reducing gas flow at a location other than the gas port, was not ideal. It works, but realistically, all we're doing is putting a band aid on the real issue - a hogged out GP.
What do I mean by oversized? Well, when I run something like my BCM or KAC uppers with a suppressor, they are reliable, gas isn't too terrible and recoil impulse is smooth. Comparatively, alot of guns would require a heavier buffer to achieve the same feel and would still dump a lot of gas in your face. My buddy's MK18, not so much. While DD makes a fine weapon, the commercial version of the MK18 uses a larger port than the one they build for the military. Why? So people don't bitch that it won't run weak ammo. Downside? Harsh recoil and tons of gas with a suppressor attached.
So what's the best solution for someone who wants to shoot suppressed, most if not all of the time? The better solution is ultimately, a smaller gas port, reducing the gas flow at the source. Problem? No one offers them specifically sized for suppressor use, ever. I've known a few guys that had connections with companies like Noveske that were able to custom order a barrel for this purpose and spec out their own gas port size. But for the masses, it just hasn't been an option. Most manufacturers don't want to bother with them because the market for a reduced gas port ("RGP") barrel is fairly narrow. It's not for your average shooter.
Well, a friend of mine works for Sionics Weapon Systems in AZ. Alot of you have probably never heard of them. The best way to describe Sionics, is that they're basically BCM, before most of you had ever heard of BCM. These guys are committed to quality, using high quality parts throughout and building solid guns. In fact, they have contracts with several police departments around the country, including Atlanta PD.
SIONICS has just released what I've been wanting for a long time. An 11.5 reduced gas port barrel, that is quality made throughout. It's currently on pre-order, so I should have it in a few weeks. And it is designed primarily for suppressed use. Per Sionics, it's for "suppressed use only" but set up correctly, can be used reliably without the suppressor too. This means, the gas port has been sized on the ragged edge of small. And that's a good thing for me. It's small enough to work reliably, but not so small that it can't serve double duty. Pros: reduced gas and recoil.
http://sionicsweaponsystems.com/store2015/5/61-5-chrome-lined-stripped.html
Barrel specs:
These Barrels are designed for use with a suppressor. We do not recommend using them without a suppressor as the weapon may not cycle properly.
These will be Limited production runs and only a handful will be available at a time. Availability will be intermittent.
SIONICS Barrels are manufactured from CMV 4150 Ordnance Steel. All Barrels are Radiograph and MPI tested.
Features:
11595E CMV 4150 Steel
M4 Barrel Extension
5.56mm NATO Chamber
1/7 Twist Rate
.750 Gas Block
Chrome Lined Chamber and Bore
SIONICS Designed Medium Contour
Manganese Phosphate Finish
Standard 1/2X28 Muzzle Threading
Carbine Gas System
X-Rayed and MP Inspected
Barrel Weight - 1 lb. 7 oz.
Build plans
Sionics 11.5 RGP barrel
BCM4 upper receiver
BCM KMR-A rail - 10"
LMT enhanced carrier (Gen 4)
BCM bolt
Standard BCM gas block
Upper will be mounted on a lower already equipped with a Vltor A5 buffer system.
I'm already very acquainted with the LMT enhanced carrier and Vltor A5 buffer system. Both are well proven additions, especially for suppressed use. My goals for this build are as follows:
Reduced weight vs my current 11.5 upper
Reliable function with / without suppressor
No adjustment or buffer swaps necessary
Minimal recoil / smooth impulse
Less gas face
Will it be the ultimate suppressed upper build? I guess we'll see. But I'm looking forward to it in a big way.
RGP barrel testing
To me, none of these solutions are really ideal. Most of them involve the addition of small set screws, detents, etc that quite frankly, I just don't trust. Sure, they work. But adjustable gas blocks started in the competitive world and have been adopted by the casual shooter. Adjustable carriers and gas keys came along as a drop in solution for folks that didn't want to screw around with the gas block. Or feasibly, something you could install and adjust without disassembling the upper.
Adjustable parts exist primarily for one reason. Too damn many companies are producing barrels with huge gas ports. That's fine if you're shooting unsuppressed and like to shoot weak steel case ammo. However, introduce full power ammo and a suppressor and you may have functional issues or the dreaded "gas face".
Regarding the use of adjustable parts, one of the things I've always felt was that while they work, reducing gas flow at a location other than the gas port, was not ideal. It works, but realistically, all we're doing is putting a band aid on the real issue - a hogged out GP.
What do I mean by oversized? Well, when I run something like my BCM or KAC uppers with a suppressor, they are reliable, gas isn't too terrible and recoil impulse is smooth. Comparatively, alot of guns would require a heavier buffer to achieve the same feel and would still dump a lot of gas in your face. My buddy's MK18, not so much. While DD makes a fine weapon, the commercial version of the MK18 uses a larger port than the one they build for the military. Why? So people don't bitch that it won't run weak ammo. Downside? Harsh recoil and tons of gas with a suppressor attached.
So what's the best solution for someone who wants to shoot suppressed, most if not all of the time? The better solution is ultimately, a smaller gas port, reducing the gas flow at the source. Problem? No one offers them specifically sized for suppressor use, ever. I've known a few guys that had connections with companies like Noveske that were able to custom order a barrel for this purpose and spec out their own gas port size. But for the masses, it just hasn't been an option. Most manufacturers don't want to bother with them because the market for a reduced gas port ("RGP") barrel is fairly narrow. It's not for your average shooter.
Well, a friend of mine works for Sionics Weapon Systems in AZ. Alot of you have probably never heard of them. The best way to describe Sionics, is that they're basically BCM, before most of you had ever heard of BCM. These guys are committed to quality, using high quality parts throughout and building solid guns. In fact, they have contracts with several police departments around the country, including Atlanta PD.
SIONICS has just released what I've been wanting for a long time. An 11.5 reduced gas port barrel, that is quality made throughout. It's currently on pre-order, so I should have it in a few weeks. And it is designed primarily for suppressed use. Per Sionics, it's for "suppressed use only" but set up correctly, can be used reliably without the suppressor too. This means, the gas port has been sized on the ragged edge of small. And that's a good thing for me. It's small enough to work reliably, but not so small that it can't serve double duty. Pros: reduced gas and recoil.
http://sionicsweaponsystems.com/store2015/5/61-5-chrome-lined-stripped.html
Barrel specs:
These Barrels are designed for use with a suppressor. We do not recommend using them without a suppressor as the weapon may not cycle properly.
These will be Limited production runs and only a handful will be available at a time. Availability will be intermittent.
SIONICS Barrels are manufactured from CMV 4150 Ordnance Steel. All Barrels are Radiograph and MPI tested.
Features:
11595E CMV 4150 Steel
M4 Barrel Extension
5.56mm NATO Chamber
1/7 Twist Rate
.750 Gas Block
Chrome Lined Chamber and Bore
SIONICS Designed Medium Contour
Manganese Phosphate Finish
Standard 1/2X28 Muzzle Threading
Carbine Gas System
X-Rayed and MP Inspected
Barrel Weight - 1 lb. 7 oz.
Build plans
Sionics 11.5 RGP barrel
BCM4 upper receiver
BCM KMR-A rail - 10"
LMT enhanced carrier (Gen 4)
BCM bolt
Standard BCM gas block
Upper will be mounted on a lower already equipped with a Vltor A5 buffer system.
I'm already very acquainted with the LMT enhanced carrier and Vltor A5 buffer system. Both are well proven additions, especially for suppressed use. My goals for this build are as follows:
Reduced weight vs my current 11.5 upper
Reliable function with / without suppressor
No adjustment or buffer swaps necessary
Minimal recoil / smooth impulse
Less gas face
Will it be the ultimate suppressed upper build? I guess we'll see. But I'm looking forward to it in a big way.
RGP barrel testing
It could be picky on ammo, but I don't expect it to be. However, the guys at Sionics have tested these extensively and they feel they've found the sweet spot to achieve the desired goal while not being too ammo sensitive. The barrel was originally designed at the request of a specific Department and intended solely for suppressed use.