Scar 17 Gas screws. Which size end all, be all thread... - Page 1

[ARCHIVED THREAD] - Scar 17 Gas screws. Which size end all, be all thread...

Posted: 11/24/2016 8:23:47 PM EDT

I'm looking to decrease the over gassing and Hardish recoil on my 17. I've read some guys swapped out their 1.5 oem gas screws to 1.35 or 1.40 and achieved what I'm looking to do. On the other hand...handl defense recommends running a 1.7 screw. So which is it? Go bigger over the oem size or smaller? I shoot suppressed 50% of the time with a sdn6 for what it's worth.

Posted: 11/24/2016 11:30:15 PM EDT

[#1]

Can't comment on suppressed, but I stepped down to 1.35 (if I remember correctly, was a while ago) and noticed it was a bit easier on the brass for reloading. After 400 rounds or so without cleaning though I do start running into FTF's and such.

Posted: 11/24/2016 11:49:35 PM EDT

[#2]

I am running a 1.3mm in my rifle. Suppressed it is flawless. Unsuppressed it also works perfectly. I have well over 2k RDS fired since changing to the smaller gas screw. At the time of change my rifle had just over 9krds fired. I have noticed no I'll effects to the rifle with this change.

Posted: 11/25/2016 6:23:46 PM EDT

[#3]

The handle defense sizes are all wrong. Look at the size reference on PMM's site.

I think I have a 1.35 in my 17.

Posted: 11/25/2016 10:04:47 PM EDT

[#4]

I just ordered 1.35 and 1.4 from Parker mountain machine.
Will start with 1.35 and move up if needed.

EDIT: barrel is standard factory 16" config on SCAR 17

Posted: 11/26/2016 7:18:19 PM EDT

[#5]

Midwest has the gas screws here: http://www.midwestgunworks.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=mgwi&Category_Code=scar-parts&view_perpage=all

On my 556 SCAR the 1.60mm gas screw gives me reliable function while reducing the force of the bolt slamming back into the buffer.

I set it up with my current ammo by starting small and firing with one round in a mag, and increasing after each shot until the bolt locked open on the empty mag. I then went up 0.1mm (2 gas screw sizes) for a little increased reliability.

AJ

Posted: 11/26/2016 10:13:30 PM EDT

[#6]

Quote History

Quoted:
Midwest has the gas screws here: http://www.midwestgunworks.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=mgwi&Category_Code=scar-parts&view_perpage=all

On my 556 SCAR the 1.60mm gas screw gives me reliable function while reducing the force of the bolt slamming back into the buffer.

I set it up with my current ammo by starting small and firing with one round in a mag, and increasing after each shot until the bolt locked open on the empty mag. I then went up 0.1mm (2 gas screw sizes) for a little increased reliability.

AJ

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I did the exact same procedure on my 17S. I ended up not toying with the 16S. In regards to gas screws, if I had to do it all over again I'd pick the ones up from PMM. If you don't have a slotted screwdriver bit that's wide and long enough the regular screws can be a pain to remove. The PMM screws with the allen head look much more forgiving in that regard.

Posted: 3/4/2017 4:30:21 PM EDT

[#7]

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Quoted:
I just ordered 1.35 and 1.4 from Parker mountain machine.
Will start with 1.35 and move up if needed.

EDIT: barrel is standard factory 16" config on SCAR 17

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Same - I ordered 1.3, 1.35, and 1.4. I started with 1.4.

I took my Scar 17 to the range today, with the 1.4 it ejected fine and didn't feel like it was beating the shit out of my shoulder. I put on a Dead Air Sandman-L and put the gas setting into suppressed and it was ejecting a nearly perfect 3:00 using I think it was Prvi 7.62...I'd have to check what was loaded in the mags to be sure but it's either that or old Port surplus. Either way - I think 1.4 might be where I stay. I ordered my gas jet/gas screw from Parker Mountain Machine. I might futz with the 1.35 and 1.3 later just to see at what point it fails to cycle, but at least I know that 1.4 works perfectly without beating me up in the process.

I don't have a comp on the muzzle; I have the Dead Air flash hider. If I spring to SBR it I'll use the comp the can came with on the short barrel as a sacrificial baffle.

Posted: 3/5/2017 10:26:25 AM EDT

[#8]

Shot the rifle yesterday with 1.35. Functioned flawlessly suppressed with gas block on suppressed setting and unsuppressed with gas block in normal setting.
Shooting unsuppressed with gas block in suppressed setting caused rifle to short stroke.
So, 1.35 puts my rifle right on the edge, recoil is very mild.

Posted: 3/5/2017 10:42:09 AM EDT

[#9]

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Quoted:
Shot the rifle yesterday with 1.35. Functioned flawlessly suppressed with gas block on suppressed setting and unsuppressed with gas block in normal setting.
Shooting unsuppressed with gas block in suppressed setting caused rifle to short stroke.
So, 1.35 puts my rifle right on the edge, recoil is very mild.

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Thanks for the info. I still haven't ordered mine lol. They were out of stock when I looked. I need to go check again. Where did you get yours?

Posted: 3/5/2017 10:59:27 AM EDT

[#10]

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Thanks for the info. I still haven't ordered mine lol. They were out of stock when I looked. I need to go check again. Where did you get yours?

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I ordered mine from Parker Mountain Machine. Wanted the stainless hex. They list 1.4 as a standard size, 1.35 from them is a special order item.

I highly recommend the swap, that and then the Geissele trigger are two best things to do to the rifle in my opinion.

Suppressor is 762-SDN-6, barrel length is std factory 16"

Posted: 3/11/2017 7:27:32 AM EDT

[#11]

I ordered the 1.4 from PMM, looking forward to them showing up!

Posted: 3/21/2017 6:01:17 PM EDT

[#12]

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I ordered the 1.4 from PMM, looking forward to them showing up!

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Went to order one but I'm not paying $8 for a gas jet and another $8.75 for shipping.

Posted: 3/21/2017 10:04:03 PM EDT

[#13]

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Went to order one but I'm not paying $8 for a gas jet and another $8.75 for shipping.

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We had three of us with SCARs combine the order, saved everybody on shipping, each got a 1.35 and 1.4, so about 20 each.

Worth it to tune the gun properly, even at 20, it is a 3000 rifle after all...

Posted: 3/21/2017 10:11:04 PM EDT

[#14]

I'll get one eventually, but I'll wait. Called and asked about cheaper shipping. Apparently when one of the employees gets off vacation they're going to make cheaper shipping an option on small parts.

Posted: 3/22/2017 6:16:06 PM EDT

[#15]

Probably gonna do the 1.4... Still in doubt that you can feel a difference in recoil however. Will have to see for myself.

Posted: 3/22/2017 6:42:41 PM EDT

[#16]

It isn't that much of a difference in recoil, but it definitely does not feel like it's beating the shit out of itself anymore with the 1.4; with the factory screw, on mine, it did feel like it was just battering itself for no good reason. I didn't even try it with the 1.5 on suppressed; I knew it'd just be overgassed. With the 1.4 suppressed, it ejects straight out at 3 in suppressed position, which is great. It ejects out at around 1:30-2 with it in the normal position, so the gas block setting definitely has an effect.

YMMV, every rifle is different, but if it lowers gas while maintaining %100 functionality, then good - why beat yourself up excessively when you don't have to...

Posted: 3/22/2017 10:21:25 PM EDT

[#17]

Anyone running a Sandman S on the Sbr 17 13 inch barrel? I have the 2.0 installed now. Wondering if I should go lower. It does kick pretty good.

Posted: 3/22/2017 11:33:44 PM EDT

[#18]

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Quoted:

Went to order one but I'm not paying $8 for a gas jet and another $8.75 for shipping.

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Jarod is a real good guy. If you call him up and tell him this he will probably ship a better way.

Posted: 3/23/2017 12:19:51 AM EDT

[#19]

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Jarod is a real good guy. If you call him up and tell him this he will probably ship a better way.

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Sounded like a nice enough guy but also sounded busy and told me they would look at adjusting shipping on those once someone there came back off of vacation. I'm in no hurry so I can wait.

Posted: 3/23/2017 8:17:41 AM EDT

[#20]

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Sounded like a nice enough guy but also sounded busy and told me they would look at adjusting shipping on those once someone there came back off of vacation. I'm in no hurry so I can wait.

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Yea. I think it's just him and someone who helps with shipping. He works from a shop in his backyard.