So maybe I'm an overlooking something obvious, but my MPX collapsible stock (thanks to Creslin!) is not collapsing.

Form 1 came back and I just hit the range for the first time with it last night.

Stock collapsed fine and locked into all 3 positions at the start of the range session. At the end, it was stuck fully extended. The locking button depresses fully, but the stock arms don't slide.

Removed the stock from the rifle and removed the block that holds the stock arms. The set screw at the bottom was loose a bit, but the two horizontal screws holding the block were in fine.

Pulled the whole thing apart and the stock arms slide freely. Screwed it all back together and it's still locked open, even though the release button traverses freely.

The operation looks simple enough, so I must be missing something, because I see nothing that would impede the stock arms and the release works fine.

Ideas?

It is kinked. One side arm is more forward than the other. Push the button pull the stock back qt the same time.

Push atock forward evenly

Mine did this called sig and they replaced it

No amount of working with the set screw would solve it, I could get it to work until I shot it again and it would lock back up. New one has been fine