AR15 ejection port door question/issue

CobraGT

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Hey all, I've lost track of how many ARs I've owned over the years... but I've run into a minor problem/issue I've never seen before. Picked up one of the SAS Colt Canada uppers from a site sponsor, and noticed when I took it out of the box that the ejection port cover was open. Didn't think much of it until I checked it over and assembled it with the BCG and CH, and noticed the port cover wouldn't stay closed - it just popped right open again when I closed it. Any thoughts? After opening and closing it a few times, it stays closed better now probably 80% of the time, but still, a rap against the magazine will cause it to pop open.

I'm not concerned enough about it to return the upper, and aside from this glitch it's awesome, but on a $1300 upper, I wouldn't expect any problems!! Is there an easy fix? I've built lots of AR lowers, but I've never ####ed around with an upper before - I've always just bought them assembled. Visually there's nothing different between this upper and any of the others I own.

Thanks!
 
My SAS upper has the same issue. Looks a little flimsy compared to my other AR. Not really a big issue unless you are down in the dirt a lot, is it?
 
There is not much to see tbh. It looks normal. If anything, I'd say mine looks very slightly bent. Mine will hold closed but seems to have a will of its own.

Possibly the spring has been rotated to many turns during assembly or the spring orientation is incorrect, notch in the receiver is out of spec, ejector port opening out of spec, Rod or door bent or twisted.

Really not much to go wrong with the hardware unless it was dropped on the right side.
 
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There is not much to see tbh. It looks normal. If anything, I'd say mine looks very slightly bent. Mine will hold closed but seems to have a will of its own.

Same... not much to see. Mine LOOKS fine, but I can take a photo or two of the port door... just let me finish getting the optic and other stuff mounted on the gun. In the middle of doing that now.

Possibly the spring has been rotated to many turns during assembly.

...so not enough tension on the little pin, then, you think?
 
Everything it in the correct orientation and the door appears to fit correctly. Have you oiled the tab/plunger spring on the door itself so it moves freely as you squeeze it? Have you removed the carrier group to ensure it seats correctly?
 
Seats the same way with or without the BCG in place. The plunger on the inside of the port cover seems to move freely, but I'll try oiling it. Thanks for the suggestions.

Edited: oiled the plunger - made no difference. Plunger moved freely before being oiled, so I didn't anticipate it making a difference. Almost seems like the port door, when closed, isn't allowing the plunger to quite settle into its detent inside the ejection port. Oh, well, if I can't figure it out, it's not the end of the world.

Just finished adding the comp and other assorted stuff - she's pretty :)

 
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