View Full Version : A SCAR gas regulator question
I own two SCAR 17s rifles. The owners manual states to run the weapon with the regulator in the 12 o'clock position. I would assume to turn the regulator counter clockwise is intended for running a suppressor. Does the SCAR accomplish this by venting the gas away from the piston? I have run both my 17s in both positions with no suppressor and both weapons have yet to have a malfunction. I find no change in the point of impact. Is there any problem with running the weapon on the range with the gas in the counterclockwise position to save the receiver from unneeded beating?
Thanks
Possum 20
If it works.... it works.
If carried for duty/defense, I would put 500rds through any service weapon/ammo configuration before carrying.
BullittBoy
04-25-11, 15:59
The position to the right should be for "adverse" or if the gun does not cycle.
I have an FS2000 and it is the EXACT same gas system. In the FS manual it says to use the setting to the right for adverse conditions. I have seen people say that when running weaker ammo such as Wolf in the .223 they have to move it to the right. In my FS2K I have had no issues, but in my SCAR 17 I had to move it to the right when running Radway Green 7.62, all the other surplus worked.
IIRC, the SCAR gas system vents more gas, while having the same port hole, in the suppressor and normal mode. Much in the way PKM's are regulated by gas exit vent size, not gas entrance port size.
The idea of "adverse" and "suppressor" setting will be opposites. You want more gas/less vent in "adverse", less gas/more vent in "suppressor" modes
I am now a little confused. The FN manual really does not say anything that I could find on the gas settings other than to run it at 12 o'clock. My visual inspection of the gas plug lead me to believe that gas was vented away from the piston when the setting was turned to the left when looking at it from the barrel end. I have only two settings that I know off unless I have had a brain fart. I just wanted to find out if the other setting was for a suppressor and to make sure that I am not doing anything stupid out of ignorance of the system. As best as I can tell I do not have an "adverse" setting. Thanks for the help I know it is a kind of lame question.
The position to the right should be for "adverse" or if the gun does not cycle.
I have an FS2000 and it is the EXACT same gas system. In the FS manual it says to use the setting to the right for adverse conditions.
This is NOT correct for the Mk16/17/20 SCAR FOW. The 10 o'clock position (or 2 o'clock depending on your orientation) is designed to vent additional gases out of the piston chamber during operation for use with a suppressor mounted. It accomplishes this via two small vent holes that line up with a groove cut into the gas block when in that position. The info can be found on page 2-60 of the SW370-A4-OPI-010 Operators Manual.
Stephen
I had the same question. Robb Jensen (Moderator and SCAR Armorer, among other things) told me the same thing Stephen just said...the 45 degree setting is for suppressed use.
BullittBoy
04-26-11, 10:25
Ok,
So how does it make sense that if I moved my gas regulator to the 2 oclock position my SCAR 17 functioned with Radway Green 7.62 but when I had it on the normal 12 oclock it would short stroke.
This was the only ammo that did this so I flipped the switch over and it worked fine after that. If there is less gas then it should have done it worse-correct?
Sttrongbow
04-26-11, 19:43
IIRC, the SCAR gas system vents more gas, while having the same port hole, in the suppressor and normal mode. Much in the way PKM's are regulated by gas exit vent size, not gas entrance port size.
The idea of "adverse" and "suppressor" setting will be opposites. You want more gas/less vent in "adverse", less gas/more vent in "suppressor" modes
Just a note.... SCARs have a screw in "gas control screw" which comes in various sizes, and allows each individual weapon to be tuned for cyclic rate. These gas control screws are essentially screw-in gas ports. Over on fnforums, I did a a post on the sizes available for the SCAR 16, as I was tuning my SCAR SBR.
This port acts in concert with the gas regulator itself.
Burt Gummer
04-29-11, 10:21
Just a note.... SCARs have a screw in "gas control screw" which comes in various sizes, and allows each individual weapon to be tuned for cyclic rate. These gas control screws are essentially screw-in gas ports. Over on fnforums, I did a a post on the sizes available for the SCAR 16, as I was tuning my SCAR SBR.
This port acts in concert with the gas regulator itself.
My post will probably go unanswered, but I give it a shot anyway...
I have zero use for the "suppressed" setting on my SCAR, and would prefer an "adverse" setting option.
Theoretically, would changing the size of the "gas control screw" convert the current "normal" (12 o'clock) to "adverse" and "suppressed" (2 o'clock) to the new "normal" setting?
No, the suppressed setting also vents excess gas.
Burt Gummer
04-29-11, 11:11
Thanks Todd!
I guess the only option would be an aftermarket gas regulator.
Thanks Todd!
I guess the only option would be an aftermarket gas regulator.
In theory, you could add a larger port size gas control screw and then a gas regulator with one normal sized opening and a the other sized to match the larger gas control screw.
Stephen
My post will probably go unanswered, but I give it a shot anyway...
I have zero use for the "suppressed" setting on my SCAR, and would prefer an "adverse" setting option.
Theoretically, would changing the size of the "gas control screw" convert the current "normal" (12 o'clock) to "adverse" and "suppressed" (2 o'clock) to the new "normal" setting?
Actually, this might work: tune the 2 o'clock position so that it becomes your "Normal" setting. When switched to the 12 o'clock position you should get a good deal of additional gas to the operating parts. YMMV
Stephen
Burt Gummer
04-29-11, 11:56
Okay, so who'll be the first to try it? :D
ETA:
I guess one needs to determine the volume of gas bleed off from the smaller two holes, and add that to the overall volume of gas control screw.
Sttrongbow
04-29-11, 17:19
My post will probably go unanswered, but I give it a shot anyway...
I have zero use for the "suppressed" setting on my SCAR, and would prefer an "adverse" setting option.
Theoretically, would changing the size of the "gas control screw" convert the current "normal" (12 o'clock) to "adverse" and "suppressed" (2 o'clock) to the new "normal" setting?
Yes, you could do that. You could use a larger GSC and then use the "supressed" setting as a normal setting. The normal setting would then become an "adverse" setting.
But you are working in the dark without hi speed video to measure cyclic rate. You may have more problems from messing with it than you really need an adverse setting.
QuietShootr
04-29-11, 18:42
But you are working in the dark without hi speed video to measure cyclic rate. You may have more problems from messing with it than you really need an adverse setting.
Agreed. I wouldn't do it.
No Bananas
04-29-11, 22:26
HEY!!:shout:If you own 2 SCAR 17s, then roll out the sexy pics!!:mad:
outta be ashamed of yourself....asking for info....witholding pics of the twins
I have an FS2000 and it is the EXACT same gas system. In the FS manual it says to use the setting to the right for adverse conditions.
Not exactly. Remove them both, take a look at the ports in the gas cylinder; they are much different. Externally it is the same valve, but the gas ports drilled into the valve are different.
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