maybe a dumb one...

I have built several uppers with low-profile gas blocks.  I recently acquired two x new Colt SOCOM barrels with FSP to assemble.  I had a baggie of generically labeled "gas tube roll pins" that I previously bought and used those for assembling the upper (Same baggie has supplied pins for low-profile gas blocks).  What I see is that the gas tube roll pin for the FSP is too long/wide and sticks out a bit on either side.  I compared this to a Colt 6920 upper and an LMT upper.  The Colt appears to have a shorter pin and the LMT appears that a punch or something was used to flatten the extra length out so the pin can't come out.


So...I intend to eventually sell the SOCOM upper (or pass on to my son), and I want it to be "correct."


Am I missing some brain cells here?  I have searched and not been able to find anything about two different gas tube roll pin sizes/lengths.


Thanks experts.


Jon

anyone?

If it is just a tad longer, I would press both sides with a pair of vice grips to flatten the sides out. That way it is a really secure.

I have a parts bin full of spare parts and some of the gas tube pins are different sizes. I just select the one that best fits. I don't put too much thought into it at all.

thanks!  just looking for some sanity check.

I, too, have a couple "longer" gas tube roll pins. They are from some low pro gas blocks that came with pin. Some blocks are shaped differently and come with a longer pin. That may have the same case for you.

I just built a upper and the gas tube roll pin was a little long and sticks out on both ends.  I would just use them.

A few years ago I was at Harbor Freight and picked up a Roll Pin Assortment. 315 pc. on sale for under $4.
It has a bunch I will never use, but plenty of the sizes needed for AR and other gun building.
I still have many left to use.
I just pick out the size I need and use it.
This may not work for everyone, but so for it has worked for me.

Ron

The correct size is a .078" x .312" (5/64" x 5/16") tubular slotted spring pin, phosphate or black oxide finish.  1/4" is probably a little short, 3/8" is way too long, but can be fixed with a file.

Stainless steel is a good alternative.

The tolerance on the length is .03" so the pin can be anywhere from .290 to .340, the thickness of the front sight in that area is .31 +/- .01 so having a bit of pin exposed is possible.

If the exposed pin really bothers you, file one shorter before installation.

thanks all.

I have these on two SOCOM uppers I am selling.  They don't bother me, but some purists may object :)