When I recieved the two rifle kits I ordered from J&T I noticed that both of them were missing the black o-ring from the ejector assembly, item 63, shown on the exploded view in the J&T Distributing AR-15 Owners Manual.Upon calling to question this, I was told that the o-ring only came on the assembled rifles sold, not on the kits and that I really did not need the part. 500 rounds later, they were right, my rifles shoot fine.
What I really want to know is what purpose the o-ring serves and what would be the expected result of installing one?
It's to aid in extraction.
To some it's the best thing since sliced bread, to others, it a solution in search of a problem.
Here's an example.
I rebuilt all my bolts using the BC upgrade kit. Can't hurt - especially on car-bean rifles.
Thanks for the info. Since I have two basically identical rifles, I will get one and run a comparison with and without.
The fact that it's missing means you don't have to go to the trouble of throwing it out yourself.
None of my ARs leak water, so I've never needed an oring yet.