Join Date: May 2004
Location: SW Washington State
The pop open issue can be caused by an improperly fitted barrel or the action isn't closed completely after loading, or oil on the locking surfaces. One cause for the action not opening is the firing pin is stuck in the primer, you may be able to move the firing pin to the rear with a knife tip or screwdriver enough to open the action, it could be caused by excess head space or too hot a load/bad chamber/excess head space binding the action up.
"Always do right, this will gratify some and astonish the rest" - Mark Twain