birdbuster - Assuming that this is a sidelock,I have the identical gun and used to have the same problem. Have you noticed that after 125-200 rds, that the pins loosen and seem to be travelling to the center of the gun? The ends of the pins that were once flush, now seem recessed? I have has several gunsmiths look at this, but only one had the apparent solution.
There is a notch on the side place in which the sears are mounted ( I know I have the terminology wrong but the principle works). As the pins loosen this relationship of mechanism to notch loosens to the point that the mechanism is no longer in contact wo the notch -- its like not having a safety sear at all.
Pull the front and Wham it doubles.
All you need to do is to keep the pins snug against the side plate. I do this when I notice the pins travelling inward. Although since really sungging these down, the travel has lessened noticably. I have shot 200 rds in a row - no double, no travel. 50 more with very hot loads, just to see. All OK. Hope this helps.
