I bought a beat to shit side sling swivel for a song and I need to know the size of the roll pin to replace it with. Best I cam come up with is 1/8x3/4 but I want to make sure before I make a special trip to the hardware store.
Roll pins are sized by the hole dimension you are putting it in.
So if it an 1/8" hole then it is an 1/8" roll pin X whatever length you need.
Clarence
The side sling mount that came with my 6920 used “spiral” roll pins instead of the common “split” roll pins. Post #9 of the linked thread mentions an issue with using the split pins on the sling mount.
https://www.m4carbine.net/showthread.php?159684-Colt-6920-Sling-Swivel-Roll-Pin-Size
Yes, the manual calls for a 1/8 x 3/4 nominal spring pin.
Roll pins work just fine…
Thanks.
Correct…
A Spirol pin is the proper pin for the side sling mount.
The “proper” pin is MS39086-93, Pin, Spring (NSN 5315-00-690-0544)
I’m the new guy and I’m not sure where you got your information… but you’d be wrong.
If it were a Colt side sling mount on my carbine, I’d use a 1/8 X 3/4 steel coiled spring pin and it would look like this…
Note that ‘proper’ was inside quotation marks…
According to the USG technical data, the pins are Military Standard spring pins.
Yes, roll pins (coiled) have a higher shear strength than spring pins.
When using regular slotted roll pins, install them so the slit is 90 degrees from the load.
The stress point of the pin when installed is at the location 180 degrees from the slit from being compressed into the bore.
So the point is do not install the slit style roll pin with the slit facing the load and the 180 degree from the slit facing the load,.
90 degrees offset from the load to ensure best service life.
Clarence
PS;
Coiled roll pins can be installed in any position cause there is really no stress point of the metal cause it coils/rolls within itself into the bore.
Also coiled roll pins can be reused.
I would not reuse a regular split type roll pin.
Hope I explained it so you can understand it.
Why not save all the headache and BS and buy the correct Colt pins and call it a day. You’re not going to go broke buying the Colt pins, hell if you check out the EE here or look around elsewhere you may find the whole assembly, New and possibly cheaper than the pins. A lot of guys remove the assembly and use something else.