First, I know what the knee jerk answer to this is, so please read the post before replying. This problem occurs with the gun unloaded.

In short, I've got a BRNO ZKK 602 that I'm having trouble with the bolt on. I don't know what the problem is but the bolt operates very stiff and it's worse after the gun is cocked. If you dry-fire the gun and open the bolt, it opens relatively easily, then closes faily stiff. Then if you try to open it again it remains stiff until you fire it again. About the only thing I can think of that might be happening would be something with the sear or something along those lines, but I can't tell. The recess for the lugs is clearand free of debris. It doesn't feel like it's binding in the front but rather at the rear. It's hard to describe. Anyone run in to this before on a Mauser?

Regards,
Tom

Hi: This is probably of no help...but it does
remind me of a Mauser bolt action I have bolt
stiffness problems with. I have a custom
rifle built on a 1909 Mauser action. On my
rifle, you could close the bolt on a round,
then the bolt would be hard to open (unfired).
When you fired a moderate load, you had to
hammer the bolt open with a rawhide mallet.
I told the gunsmith who built the barrelled
action about the problem & he said to send
it back to him. He returned it in about a
week with the terse note to "try it now".
And a fired ctg. was in the rifle, assuming
he had solved the problem. Well, its better, but not cured. It sticks badly about 1 in 3 ctgs, needing hammering to open the bolt. But others, no problem. I don't have the answer, and the gunsmith has an excellent national reputation...I don't really fault him except he hasn't solved it completely. But your comment that the bolt seems tight at the rear seems like the way mine does. I have a bunch of Mauser rifles, some custom on military Mausers with modern bolt handles, some commercial, a CZ 550 Mauser type, a Husqvarna Mauser, etc. Its the only one that binds somehow. Dunno. Its
puzzling to me.
Best Regards,
Tom

Yeah unfortunately this is a new development with this particular rifle. I took it apart tonight and looked it over real good and I can't tell what part of the mechanism is binding but it appears to be something with the way the bolt interacts with the sear. If I keep the sear from engaging, the bolt opens easily. Go figure. Guess it'll go to the gunsmith.

Cocking notch may be soft...

Check the cocking notch for gouging...

Hard to diagnose without rifle in hand- just throwing a possibility out there...

If the firing pin is straight, my knee jerk reaction would be to check and adjust the trigger sear to CP sear engagement, & then the trigger sear over travel, as it sounds as if it's either binding up the sears or the trigger sear not resetting down properly. I am assuming that this Mauser has the flat bottom cocking piece, and not the notched bottom for sear clearance.

What was your knee jerk answer to your question?

Hotshot

Hi: You've done the best thing by isolating the
problem...describe it fully to a good gunsmith
& let him work on it.

Best Regards,

Tom