A student is bringing me a Sig 1911 that he says seized up on him when firing to the point he could not move the slide or remove the magazine. He eventually got it freed up and it only happened once and now works fine. My gut tells me it may have been an overcharged round or something with the magazine. Going to look at it today. Any thoughts or insight?

Not enough info,was it greased up was it new,was the last round case swelled was the primer blown.
I know you did not limp wrist ed it

Examined the gun and magazine today. It appears when he slammed the magazine into the magwell it was done with sufficient force to deform the polymer baseplate which caused the magazine to bind the slide