Are you sure the correct buffer spring is installed?

Do you have a recommendation? I welcome any ideas you have.

Looking at Aero Precision’s web site, they have a chat function. They also have a customer service phone number. You might want to contact them and see if they will repair it under warranty.

I haven’t had the need to use their customer service much, but when I did, it was top notch.

On AR15's an extra "something" with the extractor spring is often the fix for carbines with dwell/extraction issues. I wonder if they don't know this from the get go and add the second ring proactively.


Your "hard to work the bolt" comment reminded me years ago of a used upper I bought that the gas tube was completely in front of the pin. So it was jammed in the carrier and when you pulled it back with considerable difficulty, the gas tube went with it. I doubt that's your problem though, since you've had more than one.
Wondering if you got something in your gas key and that's what gacked the first tube. Stranger things have happened.

I used the chat function to contact their customer service. They gave me an address to send the upper and said they would look it over and repair whatever needed to be fixed. I provided an invoice number, which they said they couldn't find in their records. I'll send a copy of the invoice. It would be great if this was a warranty repair but I'm far more interested in getting the darn thing to work reliably.

As to the possibility the gas tube is jamming on the bolt. There is no sign of deformation at the tube.

I'll let you guys know when the upper comes back from Seattle.

Who built the lower?