Sear Adjustment on the QB57 Air Rifle

Recently we received the following email from a customer who was encountering an issue with his QB57 air rifle. It read...

“Hello, I am wondering if you can give me some advise? I have QB57 airgun that when cocked and lever is completely closed, fires by itself, safety on or off. It only has a few hundred rounds shot through it and has just started to do this. Is there an adjustment that could be made easily?”

Obviously this is a safety issue but it is easy to correct and my reply was as follows:

“The sear adjustment screw (Part 2208) can sometimes work loose due to oil on the threads from manufacture. The screw can then back out a little from its factory setting. If it does this, misfires can result. Simply adjusting the screw should cure the issue.

To do this, remove the rear ‘main’ wood stock by unscrewing the screws 4700 and 4400. The stock just lifts off the action.

Viewing the rear trigger group from below, you will clearly see the slot head screw Part 2208. This can be adjusted in very small increments - 20 degrees rotation at a time or less - until the misfiring clears. Reassemble the gun in the stock each time for testing. Once you find the setting that prevents misfres, the screw can be fixed in place with a drop of Loctite BLUE threadlocker.”

The customer replied:
“Thanks Steve, I followed your instructions. Problem fixed!”

Below is a scan from the QB57 Owners Manual showing the location of Part 2208, the sear adjustment screw.