I’d like to order a bunch of gas tube roll pins for a project, but I don’t want to spend $1 a piece or something for a $0.03 part. It appears to be a COTS part, but I’m not sure which size to order. Does anyone know the part size to order? Is this inadvisable for any reason (along the lines of using a hardware store cotter pin as a firing pin retaining pin)? Any reason not to use stainless?
For clarity, I’m talking about part #65 in the diagram here.
Thanks in advance!
I think the standard size is 5/64 in x 5/16 in
"Knowledge is good." Emil Faber, date unknown.
McMaster-Carr sells them, it is a COTS part. I have the part number somewhere. You can order them a hundred at a time. That is what I did.
I'll look for that list and post it here when I find it.
That’s great, thank you!
Originally Posted by Super77
The following is (or was) what Sionics uses for their rifles - originally spec'd per Will Larson.
The stainless version is "better" than the original .milspec pin.
McMASTER-CARR
Gas Tube Roll Pin, 5/64 x 5/16, Part No. 93740A622
https://www.mcmaster.com/catalog/131/3822/93740A622
Will provided the complete list of McMaster-Carr parts for Roll Pins and Screws in his Semper Paratus Armorer course.
Bolt Catch Roll Pin, 3/32 x 7/16, Part No. 98296A837 (Qty 500)
Ejector Roll Pin, 1/16 x 3/8, Part No. 98296A023 (Qty 500)
Forward Assist Roll Pin, 3/32 x 5/8, Part No. 98296A849 (Qty 500)
Gas Tube Roll Pin, 5/64 x 5/16, Part No. 93740A622 (Qty 50)
Trigger Guard Roll Pin, 1/8 x 5/8, Part No. 98296A879 (Qty 250)
Gas Key Socket Head Cap Screw, 8-32 x 1/4, Part No. 91251A190 (Qty 100)
*Note - Sionics now uses OCKS (Optimized Carrier Key Screw) for Gas Keys
http://www.m-guns.com/tools.php
Gas Block Pointed Set Screw, 10-32x 3/16, Part. No. 90289A337 (Qty 100)
Last edited by tango-papa; 03-16-2025 at 05:09 PM.
Amazing information, thank you!!
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