Action lever will not stay in place when closed

Had same problem with old 12/15 model. Solved it this way. In the groove into which the lever rests when the action is closed, I drilled a 1/4 inch diameter hole, 1/2 inch deep. Then, placed a rare earth magnet with a drop of glue into the hole. The magnet was installed so that it fits flush with the wood groove. Works like a charm. Magnet holds lever in position with no trouble. Go on Google to find rare earth magnets. They are very strong and come in various sizes.

Sir, Thank you for the reply, very cleaver. Would have never thought of that. Thanks so much. James.

Is the lever just slipping forwards, or actually opening the breech? If it's the latter, would a magnet just be a bandaid on a wound? When the lever is closed it locks the breech. Is something worn in the action that's allowing the breech to open so easily? A magnet might hold the lever in place, but won't fix any internal problem.

Sir, the action is closing and staying shut, until bumping the lever. If there is a problem, where might I look to find it? And, what might be a fix? Thank you for the Inquiry. James.

I'd look at the top of the lever where it engages the breech block, the corresponding notch in the breech block itself, and the axis pin that the lever pivots on.

It might help to remove the breech from the receiver to see what's happening, and where.

Francotte/BSA pattern. (Don't know about the International) Is the lever drooping when cocked? It shouldn't. After firing it may be loose.

Cause, worn goose neck on tumbler. (If loose when cocked) Worn sear notch on tumbler or worn sear nose on trigger.