Thread: Solving a Sako design fault

The Sako .22 P94S has a design fault in the bolt locking ring which can cause the bolt handle and locking lug to break off the bolt during opening. This problem is caused by a combination of a steep cocking cam and a stiff mainspring coupled with a design that has a stress point and one unsupported edge. The stress point is created by the sharp internal corner in the slot milled for the striker and safety plunger. This stress point can create (over time) a small crack across the base of the locking/bolt handle lug leaving only a thin wall on one side holding it together. Eventually this thin wall fractures with the amount of force needed to lift the bolt handle. As the photos show, I have redesigned the problem area and made a new locking ring from Chrome-Moly 4140 steel. A lot of work on both lathe and mill but a pleasing result. The only reason I did this is because no spares are available and I believe the design has been changed in later models. The rest of the rifle is in near new condition and justified the work. If you have a similar problem don't come to me!