257 stw sticking

[Darkhelmet]

i have a 257 stw built on a trued rem.action. It doesn't matter what grain powder i use, every shot the bolt will not unlock. I'm at wits end messing with this thing! any thoughts as to what could be going on?

 

[JeffP40]

Is the bolt opening most of the way, or not at all? I am assuming the brass is formed from 7mm? Does it fit fine before loading? I am thinking it has to do with brass forming. I can't imagine the rifle being the problem, but stranger things have happened. I would check the brass even down to placing an empty in the chamber and pulling the trigger, then extract. If this is fine, I would begin to think it is a bad chamber. Oblong or off-center. Without excess pressure, that is the only way I can think of to cause this.