I have had a FM-9 in the box for longer than I should admit and finally got it out.
Initially ran 10 round belts through it to ensure function but once I hooked up a larger belt or tried to run a 150 round bag the belt would pull apart.
Specifically, the belt inside the feed chute would pull apart by stretching the single arm of a link out, causing the belt to separate. This was consistently at the point between 3 rounds or so and the rest of the belt.
The links and upper were purchased in 2019. Ammo was S&B 115gr. Semiauto, standard strength buffer spring and buffer.
I've emailed Freedom Ordnance but thought I check here first.
Any help would be appreciated.