SCAR 16/17 and Back Pressure

[Strykervet]

So I finally scored a new 16 and only got "gently raped" at a tad over MSRP, should have gotten it years ago. My 17 is on order with a dealer at .mil pricing. I can't complain, all considered.

I know about FN regarding suppressors and warranty work. Shit about back pressure. How much of a deal is back pressure, really, with the Mk16/17 rifle? Is an AAC 556SD or a Sico Saker for 5.56 or AAC SDN6 for 7.62 gonna fuck one up? Hammer the internals like FN claims? I got a FA762SS for the Mk20 but don't really wanna use that setup on these two, would like to avoid buying new cans right now.

I'm SBR'ing the 17 with a 13" bbl., figure on SBR'ing the 16. Probably a 10.5. Factory barrels. Do I need gas jets? What about those rubber buffers? Is there an ideal, uh, "configuration" for a suppressed SBR SCAR? A "recipe"? What works best?

Anything else you feel prudent I should know, fill me in. Wanna keep these mostly stock though.

 

[JohnDeereGuy1996]

I would just tune with gas jets or use the mototech scarberator. If you need to send back for warranty work just turn it back stock. This is what I plan on doing when mine arrives.

 

[Strykervet]

I guess I need to educate myself on gas jets then and how they work with SBR's... I wish I knew as much about these goddamn things as I do about AR's. I figure one of those rubber buffers can't hurt though. I understand the same issue that causes these to eat optics is the same issue that causes them to wear out faster and that suppressors aggravate this.

I notice AAC recommends NOT to use brakes on these rifles... Is that because it adds to the damage or because of how they thread the barrels? Or maybe both?

Still need to know if the AAC 556SD is a suitable can for this rifle. I know the old SCAR 17 can was an AAC reflex model similar to the SDN6. I have a couple of those I can use on the 17 and already fitted the 13"bbl. with one. I figure the 556SD is similar enough to the SDN6 that if works then the other should too but that's not a guarantee. I also have a Saker I can use but I don't think any of them are "low back pressure".

 

[JohnDeereGuy1996]

I guess I need to educate myself on gas jets then and how they work with SBR's... I wish I knew as much about these goddamn things as I do about AR's. I figure one of those rubber buffers can't hurt though. I understand the same issue that causes these to eat optics is the same issue that causes them to wear out faster and that suppressors aggravate this.

I notice AAC recommends NOT to use brakes on these rifles... Is that because it adds to the damage or because of how they thread the barrels? Or maybe both?

Still need to know if the AAC 556SD is a suitable can for this rifle. I know the old SCAR 17 can was an AAC reflex model similar to the SDN6. I have a couple of those I can use on the 17 and already fitted the 13"bbl. with one. I figure the 556SD is similar enough to the SDN6 that if works then the other should too but that's not a guarantee. I also have a Saker I can use but I don't think any of them are "low back pressure".

Parker mountain machine has a pretty good video on YouTube explaining a lot of this I’ll try and link it

 

[Strykervet]

Thanks, I need to look into some videos I guess, I'll look for that, I'm sure I can find it if it's there.

I was just hoping there'd be more folks around here with more, uh, SCARperience? First hand info from experience is usually best.

 

[Gasgun]

AAC and SiCo cans are very high back pressure.
There are far better choices. SureFire, OSS being two.

 

[Strykervet]

AAC and SiCo cans are very high back pressure.
There are far better choices. SureFire, OSS being two.

Yeah, but I have seven of those already.

These rifles originally used AAC cans that were very similar so that makes it kinda confusing, are they okay or not on an SBR?

Even if I do spring for new Surefire cans down the road I'd like to be able to use these in the interim.

 

[EIGTM1651]

FWIW I run a 556-RC2 and 556-MINI2 on my 16S SBR and 762-RC2 on the 17S SBR. Full size cans have some gas to the face, the MINI2 runs great with very little back pressure. Im running the factory gas jet that came with the SBR barrels.