Roll Pin Equivalent

[hg8057]

I recently purchased a railed gas block to replace a FSB on my carbine. The railed block is a high profile CMMG with a bayonet lug (no roll pin included). One thing that stands out is that it's very thick from side to side. Where the gas tube pin goes, it's 3/4". I'm looking at my FSB and the roll pin there is I'm guessing 3/8". I did some research and found from another source that the gas tube pin diameter is 5/64". At my local ACE Hardware they have several different lengths in 5/64" diameter. Is the 5/64" diameter of the gas tube roll pin accurate?

[UWone77]

You're looking to find a roll pin for the gas tube?

5/64 that's 1/4" long should work.

I normally just buy gas block roll pins from Brownells or Rainier Arms.

If you buy a gas tube from places like BCM, they will include the gas tube roll pin with the tube.

[hg8057]

Yep, just a roll pin. But, one that's just a bit longer than the usual.

ACE has 'em at 5/64" x (up to) 3/4". I figured I'd give a 5/8" a shot to keep the ends below the side of the 3/4" thick gas block.

[UWone77]

So you decided to get the exposed gas block? That's probably not going to work with the ALG Rail if that's what you plan to do.

[hg8057]

Here's the source of my info:

Credit to BradH posting on AR15.com

www.mscdirect.com MSC has machine tools, hardware, etc

Item # 67501122
Desc 1/16 x 7/16 Coiled Spring Pins-EJECTOR

Item # 67501445
Desc 3/32 x 7/16 Coiled Spring Pins-BOLT CATCH

Item # 67501569
Desc 3/32 x 5/8 Coiled Spring Pins-TRIGGER GUARD, REAR SIGHT, FORWARD ASSIST

Item # 67594085
Desc 1/16 x 1/4 SPRING DOWEL PIN 420 SS-FORWARD ASSIST PAWL

Item # 67501163
Desc 1/16 x 1/2 Coiled Spring Pins-WINDAGE KNOB

Item # 09265067
Desc -006 VITON PAK OF 100 VITON O-RINGS -EXTRACTOR O-RING

Item # 67594481
Desc 5/64 x 3/8 SPRING DOWEL PIN 420 SS - GAS TUBE........1/16" TOO LONG, TRIM

Item # 00073379
Desc 1/8 SS440 GRADE 100 440-C STAINLESS BALL100PK - REAR SIGHT BALLS

[hg8057]

So you decided to get the exposed gas block? That's probably not going to work with the ALG Rail if that's what you plan to do.

Oh, I'm sorry. This block is for a DPMS Carbine I've owned for awhile and wanted to go to flip up sights front and rear. The LW build for the wife is a different one.

[UWone77]

Oh, I'm sorry. This block is for a DPMS Carbine I've owned for awhile and wanted to go to flip up sights front and rear. The LW build for the wife is a different one.

Gotcha.

The 5/64 in 5/8 length should work without issue for you.