Parker hard to open

[GH-16]

More than likely an ammo/primer issue.

I've had the same problem with several Parkers and found that when I switched ammo to a different type the problem went away. Nothing scientific here, but my experiences have usually been when using the promo low budget type of ammo for some reason.

I've also had the same experience to a lesser degree with Fox's as well, with the common denominator being the ammo/primers used.

[Mike of the Mountain]

Usually soft primers and they puncture easily or very hard primers and the firing pins hang up in them. The shells we see here a lot too especially with the cheaper shells. Seems the heads swell up in some guns and hang up in the chamber preventing the gun from opening. 99.9% of the time as soon as you switch primers or use a better quality shell the problem goes away.

[Double Lab]

It's the steel vs. brass on the head. Older ammo and quality ammo usually solve this problem.