Likely they don’t even have a spec for that.I bought a CZ over/under in 20 gauge. It takes somewhere between 20 to 35 lbs of pressure on the top lever to open it. I sent it back and their response was "within specs". BS, been shooting over/under and single shot all my life. Never had a problem with the top lever. I passed it around the trap/skeet field and 2 people couldn't even unlock it. I have approx 800 rounds on it, so it is well broken in. Never and I mean never will I buy another CZ rifle or shotgun. It's a shame too, It shoots both barrels as straight as any gun I have owned, but to pull the WITHIN SPECS stuff and I am done.