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Suppressing the SCAR-17 - what do I need to know? Login/Join 
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Picture of D4Heavy
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quote:
Originally posted by Brett B:
Since the 17S has a very small shoulder on the barrel, you have to be mindful that the muzzle device seats squarely. All of my SiCo muzzle devices have worked perfectly by just threading them directly on. Do not use the factory jam nut with an aftermarket muzzle device, it will cause big problems.

If you want to verify that everything is properly aligned to eliminate the chances of baffle strikes you can use a precision ground rod to check bore concentricity. Here is a thread I started several years ago where I documented some findings and shared the info for buying the ~$5 bore rod (cheap insurance for peace of mind):

https://fnforum.net/forums/sbr...ty-measurements.html

You should also consider buying a variety of different gas control screws from Midwest Gunworks. If your 17S is a little bit overgassed from the factory (which is highly likely), then it may be VERY overgassed even on the suppressed setting if you use a can that increases backpressure substantially. It's hard to predict this since all cans are so different. If the rifle is overgassed, swapping to a smaller gas screw makes a big difference in how much the rifle moves under recoil with a can.

https://www.midwestgunworks.com/page/mgwi/prod/FNSGCL


BrettB, what size gas block screw do you recommend starting with for a can? I use the SiCo Omega.
Looks like there are 15-20 sizes from 1-2mm
 
Posts: 272 | Registered: December 23, 2015Reply With QuoteReport This Post
Go ahead punk, make my day
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I went from the 16" OEM length to 13" cutdown barrel and suppressor (AAC-762-SDN6).

1.40MM is what I finally settled on, working both suppressed and unsuppressed down to M80 FMJ type loads (non-Wolf or other stuff).
 
Posts: 41966 | Registered: July 12, 2008Reply With QuoteReport This Post
Middle children
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Picture of Brett B
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quote:
Originally posted by D4Heavy:

BrettB, what size gas block screw do you recommend starting with for a can? I use the SiCo Omega.
Looks like there are 15-20 sizes from 1-2mm



First I would buy this mini drill bit set for $5. With this you can accurately measure your current GCS size, and then measure the replacement sizes if they aren't labeled or if you mix them up sometime in the future.

https://www.amazon.com/gp/prod...ilpage?ie=UTF8&psc=1


On a factory 17S 16" barrel your GCS is probably 1.5mm. I would buy a few incremental sizes down to 1.3mm to start with. Work your way down in sizes with 1 round in the mag ensuring the bolt locks open. When the rifle short strokes go up a size or two for margin. Do this unsuppressed first and then add the can and test it again. A lot of this depends on what ammo you shoot, and cold temps also affects things (shooting in very cold temps requires some additional margin on GCS size).

Make sure you soak the GCS threads in the gas block with some PB Blaster before you try and remove it. It can get stuck if it's been in there for a while.




I firmly believe that any man's finest hour, the greatest fulfillment of all that he holds dear, is that moment when he has worked his heart out in a good cause and lies exhausted on the field of battle - victorious.

-Vince Lombardi
 
Posts: 2414 | Location: Ohio | Registered: September 06, 2008Reply With QuoteReport This Post
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Picture of Brett B
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Originally posted by Gustofer:
I ordered a Sandman L for mine and was able to fondle it yesterday. Unfortunately it'll be who knows how long before I get to bring it home.

There is an issue with the barrel as it has no shoulder but Dead Air makes a special brake specifically for the 17 that they will include with the suppressor. You just have to let them know or they'll include their standard one.

It was quite spendy, but it gets great reviews, so...hopefully I'll be happy with it.


Be sure and post some feedback when you get to shoot it!




I firmly believe that any man's finest hour, the greatest fulfillment of all that he holds dear, is that moment when he has worked his heart out in a good cause and lies exhausted on the field of battle - victorious.

-Vince Lombardi
 
Posts: 2414 | Location: Ohio | Registered: September 06, 2008Reply With QuoteReport This Post
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Picture of D4Heavy
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Thanks for the info Rhino and Brett, this gives me a good starting point.
 
Posts: 272 | Registered: December 23, 2015Reply With QuoteReport This Post
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I have an OPS 12th in .30 for my 17. The two point mounting is a bit of a pain but it is a great can with a very pleasant tone.

If I was buying today I'd likely look hard at the Sig cans based on price with their mil le program and reviews. Do you know some folks with cans? Id say go shoot a bit or even go to a silencer shoot if theres one near you.
 
Posts: 1872 | Location: Western Wa | Registered: March 21, 2009Reply With QuoteReport This Post
Go ahead punk, make my day
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Originally posted by D4Heavy:
Thanks for the info Rhino and Brett, this gives me a good starting point.
And it's an easy process to do, just a little time consuming. Remove the regulator, remove / replace the GCS, install the regulator, shoot with different ammo in different configurations, suppressed and non.

I started high (overgassed) to low. Eventually you still get function with milspec ammo but the powderpuff starts failing to lock back the rifle after the last round. Load 1 round in a magazine each time and it's easy to see. That's how I ended up on 1.40mm with my SBR'ed 17 for suppressed and non use.

Hasn't given me a lick of trouble since that hour of work at the range several years ago.
 
Posts: 41966 | Registered: July 12, 2008Reply With QuoteReport This Post
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Picture of deepocean
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quote:
Originally posted by RHINOWSO:
I went from the 16" OEM length to 13" cutdown barrel and suppressor (AAC-762-SDN6).

1.40MM is what I finally settled on, working both suppressed and unsuppressed down to M80 FMJ type loads (non-Wolf or other stuff).


Did you use the AAC mount? Is there anything special one needs to do to account for the short shoulder? Any tips on how not to scratch everything up when taking it apart?
 
Posts: 6205 | Registered: March 24, 2008Reply With QuoteReport This Post
Go ahead punk, make my day
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quote:
Originally posted by deepocean:
quote:
Originally posted by RHINOWSO:
I went from the 16" OEM length to 13" cutdown barrel and suppressor (AAC-762-SDN6).

1.40MM is what I finally settled on, working both suppressed and unsuppressed down to M80 FMJ type loads (non-Wolf or other stuff).


Did you use the AAC mount? Is there anything special one needs to do to account for the short shoulder? Any tips on how not to scratch everything up when taking it apart?


I use the AAC Blackout FH Mount, it's been awhile so I don't recall if I got a specific mount - and Marvin Pitts of Nefarious Arms did my barrel cut down and mount installation. So sorry, no real help.
 
Posts: 41966 | Registered: July 12, 2008Reply With QuoteReport This Post
Nature is full of
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Picture of deepocean
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quote:
Originally posted by RHINOWSO:
I use the AAC Blackout FH Mount, it's been awhile so I don't recall if I got a specific mount - and Marvin Pitts of Nefarious Arms did my barrel cut down and mount installation. So sorry, no real help.


No worries, I thought I remembered stories from the FN Forum where people scratched the daylights out of their barrels.
 
Posts: 6205 | Registered: March 24, 2008Reply With QuoteReport This Post
Go ahead punk, make my day
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I'd reach out to Parker Mountain Machine or Marvin Pitts to see if they have recommendations.

PMM might be better because they seem to be more responsive than the last time I corresponded with Marvin, but that may have improved IDK.
 
Posts: 41966 | Registered: July 12, 2008Reply With QuoteReport This Post
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Picture of DC3S
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Getting in touch with PMM up in New Hampshire would be worthwhile.

http://www.parkermountainmachi...0/SCAR_16%2F_17.html

https://youtu.be/otiPvTUNPpM

The guys at Q also have some interesting stuff.

https://www.liveqordie.com/products/cherry-bomb-by-q/



"Freedom is a light for which many men have died in darkness."
 
Posts: 134 | Location: FL USA | Registered: February 03, 2017Reply With QuoteReport This Post
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Originally posted by dry-fly:
OSS cans are suppose to be better than others concerning back pressure... I can’t confirm though, I’ve never handled one.



I like the design of the OSS HXQD 762. Seems to really help with back pressure.

https://youtu.be/ZOisNmQUYuo

https://youtu.be/MA2OO5yld28



"Freedom is a light for which many men have died in darkness."
 
Posts: 134 | Location: FL USA | Registered: February 03, 2017Reply With QuoteReport This Post
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Picture of Rustpot
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Originally posted by DC3S:
The guys at Q also have some interesting stuff.

https://www.liveqordie.com/products/cherry-bomb-by-q/


They have a SCAR-specific muzzle device planned, I have no idea when. The standard Cherry Bomb needs a shoulder adapter. Per Q when I emailed asking about compatibility.

I'll be getting my SCAR 17 setup once my Trash Panda gets out of jail. I'm holding off hoping their SCAR bomb comes out soon.

I've also got a 8.3" 300 and a Q 16" 300 barrel to pair with the can.
 
Posts: 5680 | Location: Romeo, MI | Registered: January 03, 2009Reply With QuoteReport This Post
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Picture of DC3S
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quote:
Originally posted by Rustpot:
quote:
Originally posted by DC3S:
The guys at Q also have some interesting stuff.

https://www.liveqordie.com/products/cherry-bomb-by-q/


They have a SCAR-specific muzzle device planned, I have no idea when. The standard Cherry Bomb needs a shoulder adapter. Per Q when I emailed asking about compatibility.

I'll be getting my SCAR 17 setup once my Trash Panda gets out of jail. I'm holding off hoping their SCAR bomb comes out soon.

I've also got a 8.3" 300 and a Q 16" 300 barrel to pair with the can.



Q certainly have some interesting stuff in the pipeline. They are taking the managed growth path, smart, but frustrating if you want it now, say like a Honey Badger pistol and a Thunder Chicken.



"Freedom is a light for which many men have died in darkness."
 
Posts: 134 | Location: FL USA | Registered: February 03, 2017Reply With QuoteReport This Post
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Picture of D4Heavy
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Got some variable size GCS in today so I tried to take my stock one out. It looks like it has a flat head slot so I tried to remove it after soaking in some PB blaster. It ain’t coming out... the very small slot stripped as soon as I put pressure on it. any suggestions? Can’t get an easy out down in the whole. The guide hole above it is too small. I’m thinking I might have to send it off to a gunsmith. I checked the hole on my stock GCS and it’s 1.6. I used the mm drill bit set suggested above.

Thoughts Brett and Rhino?
 
Posts: 272 | Registered: December 23, 2015Reply With QuoteReport This Post
Go ahead punk, make my day
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I'm pretty sure OEM had a metric hex and not a slot, but let me take a quick look at mine.

ETA - I was incorrect, OEM screws do have a slot for a flat head, several of the aftermarkets I sourced have a metric hex fitting.

Both mine were removed by the gunsmith who chopped the barrel (Marvin Pitts), so I would assume you might need to do that or drill it out yourself.
 
Posts: 41966 | Registered: July 12, 2008Reply With QuoteReport This Post
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Picture of D4Heavy
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Thanks for checking. It didn’t look like it had a hex head but I couldn’t really tell. I’ll look into options of drilling it out. I really want to find the correct setting. I am pretty sure it’s over gased at 1.6 mm.

Update** I got it out! I found an easy out set I had with left hand drill bits. I had to remove the front sight post to drill it out. Soaking over nite in PB Blaster probably helped too. Now time to hit the range with the different sizes and dial my Scar in.

This message has been edited. Last edited by: D4Heavy,
 
Posts: 272 | Registered: December 23, 2015Reply With QuoteReport This Post
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Using a Surefire Socom mini with mine and have had good results and no malfunctions
 
Posts: 12 | Location: TN | Registered: February 07, 2019Reply With QuoteReport This Post
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the factory seem soft to me, if I still had my 17s I would use PMM. I settled on 1.4mm when I was running mine supressed with an Omega 300


"All that is necessary for the triumph of evil is for good men to do nothing"
Edmund Burke
 
Posts: 488 | Location: Florida | Registered: February 18, 2004Reply With QuoteReport This Post
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