15P gas control screw

689 Views 13 Replies 4 Participants Last post by 670, 2 mo ago

kilyung

Just measured my 15P’s gas control screw as a baseline - came with a 1.2 mm screw. I’ve got blank set screws to make new sizes but need to shoot it more before making changes. Has anyone else played with the gas yet?

Correction: stock jet is 1.2mm - my pin gages were mixed up

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LaChupacabra1

· #2 · 2 mo ago

Buy 3-position Scarburator.

3-Select Regulator | Mototech Engineering

www.mototecheng.com

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kilyung

Discussion Starter · #3 · 2 mo ago

That’s a good idea but while I like Eddie’s regulator (looks OE) the scarburator doesn’t look right to me when not covered by an extended rail. Besides for $150, I can buy a lot of screws.

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Grinder

· #4 · 2 mo ago

kilyung said:
Just measured my 15P’s gas control screw as a baseline - came with a 1.1 mm screw. I’ve got blank set screws to make new sizes but need to shoot it more before making changes. Has anyone else played with the gas yet?

That sounds really small when 10 1/2" 16s are 1.8-2.0 range

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kilyung

Discussion Starter · #5 · 2 mo ago

I know right? I was very surprised at how small it was. I have a set of certified pin gages that I used to measure it. I wonder how small I can go…

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Grinder

· #6 · 2 mo ago

kilyung said:
I know right? I was very surprised at how small it was. I have a set of certified pin gages that I used to measure it. I wonder how small I can go…

I haven't taken mine apart yet.
They must have changed some things internally
Where did you buy the pin gages ?
I've ben meaning to get a set

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kilyung

Discussion Starter · #7 · 2 mo ago (Edited)

Grinder said:
I haven't taken mine apart yet.
They must have changed some things internally
Where did you buy the pin gages ?
I've ben meaning to get a set

Got the Class Z Go 65 piece set from McMaster-Carr years ago.

The bolt carrier is lighter than the 16S one so that may have resulted in a smaller gas screw.

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LaChupacabra1

· #8 · 2 mo ago

kilyung said:
That’s a good idea but while I like Eddie’s regulator (looks OE) the scarburator doesn’t look right to me when not covered by an extended rail. Besides for $150, I can buy a lot of screws.

3-position is the same like OEM.

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kilyung

Discussion Starter · #9 · 2 mo ago

You mean the regulator (not scarburator)? I’ll have to dig it up and give it a try to see what happens.

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LaChupacabra1

· #10 · 2 mo ago

Yes. OEM regulator is same dimmension like 3-select regulator from Eddy.

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kilyung

Discussion Starter · #11 · 2 mo ago

I should also point out that the gas block is about 2” further back as compared to the 16S.

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kilyung

Discussion Starter · #12 · 2 mo ago

Just got done testing some jet sizes at an indoor range. Ammo used was 200 rounds of 77gr IMI SMK. I started low and moved up if any issues popped up with 0.8, 0.9, 1.0, 1.1, 1.2 size jet screws. Stock jet size is 1.2mm (corrected in original post). Regulator was left on normal mode as I don’t have a baffled suppressor for this barrel length.

0.8 - FTE
0.9 - FTE
1.0 - FTE*
1.1 - reliably extracted
1.2 - reliably extracted

* 1 FTE in a 20 round mag. I shot an additional 20 rounds on 1.0 using 55gr PPU M193 with no FTEs. Lovely fireballs!

I’ve settled on 1.1mm for further testing. It seems smoother than the stock 1.2mm but not so much that it’s worth swapping screws - I make my own gas screws so no biggie. I also tested with my OSS suppressor and the 15 is surprisingly tame suppressed. I initially had 4 light primer strikes with the IMI ammo but that cleared up as I continued shooting. I will be installing an extra power hammer spring to mitigate this in the future.

After 240 rounds, I’m loving my 15. It shot out a fist size hole at 10yds. My modified PDW stock is solid and I’ll continue monitoring it every session. Next, I need to get the 15 sighted at 50yds and test its accuracy.

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