Having actually used the Menck tool to successfully remove a couple of striker discs w/o buggering up either the striker disc or the breech face I don't think I would change any thing if building one from scratch.
The adjustable spacing of the design allows a very precise fit of the pins to the striker disc holes & once adjusted is very solid.
The one thing I would change is the instructions for use:
1. To prevent burring the holes in the striker disc I first precisely fit the pins to the holes (I bought extra pins when I ordered my tool) leaving the original diameter on the back side of the pin where it fits into the tool face.
2. I would not use the recommended impact driver unless I had tried all other alternatives first. With the 1/2" drive you can provide plenty of torque with a T handle or breaker bar & have a lot more control of the tool & if that didn't work I would set it up in a vertical mill or heavy drill press so you could maintain heavy pressure on the tool while turning it by hand (same technique as used for really stuck screws).
The objective is to remove & replace the striker disc & having it look like it was never removed in the first place. This may not be possible in all cases & at the very least we want to avoid marring up the breech face. New striker discs can me made & fitted if all else fails but the breech face is difficult to repair.
