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Discussion Starter #1 (Edited)
I get PMs asking this and that regarding smoothing up function of the P22 and one question that is always important is what happens if my hammer will no longer cock. So, I thought I would address that just a bit.

First, in DA, the hammer is never caught by the sear. Pulling the trigger begins to move the trigger bar rearward. The rear of the trigger bar engages the hammer strut and begins cocking or rotating the hammer more and more rearward until the hammer is released. But how does this occur? Two slanting, steel pins fastened into the sides of the frame engage the outer, rear edges of the trigger bar and as the trigger continues to be pulled these bars cause the rear of the bar to slide downward. The center of the trigger bar is caught in a notch at the front of the hammer strut. As the rear of the trigger bar slides downward the center portion of the rear of the bar begins to move downward and out of the slot it has engaged on the hammer strut. This continues until the hammer strut breaks from the trigger bar. There is a nose on the front of the hammer strut that slides along the floor of the frame and will not let the strut move downward as the trigger bar moves to disengage. When the hammer is released, the rear legs of the trigger bar must remain raised just enough so that the rear vertical legs remain engaged with the lower legs of the sear. This keeps the sear rotated out of the way of the falling hammer so that the hammer isn't caught in the half cock notch.

Fitment and timing of movement of these parts is pretty critical, there is a bit of safety factor engineered into the parts to overcome wear as it occurs so you can't just go in there sanding and filing on this and that. Polish only.

But SA is what I want to address. SA is when the hammer is cocked and held cocked by the sear catching the hammer in the full cock hammer hook notch. The sear is spring loaded in a manner that the noses of the sear (there are two) constantly drag against the hammer seeking an opportunity to catch in one of the notches. Walther has designed a small amount of extra gap between the nose of the sear and the face of the hammer hook when the hammer is rotated fully rearward. This allows time and space for the sear to engage the hammer when firing. It also provides a margin of distance for the sear to drop in place as parts might wear a bit, such as the bearing surfaces between the slide and frame.

You can observe this extra space space by carefully watching the hammer. When the slide is retracted over a stock hammer the sear drops into place to engage the cock notch. But there is some extra space. You can see this when you slowly move the slide off of the top of the hammer. The hammer will follow appx. 0.020" until the hook comes into contact with the sear. So when you might polishing the face of the hammer to remove the tip there you can reduce the amount the bottom of the safety drum presses the hammer rearward. If it isn't pressed far enough rearward....the sear will no longer engage the hammer hook, i.e., the hammer won't be caught and held in a cocked position. The cure here is to remove a small amount of steel from the hammer hook face.....but this is pretty tricky work, not removing too much and keeping everything square. Remove too much and you create a much larger gap which lets the hammer follow the slide forward even more than the 0.020" and which in turn might undo other work you might have done. You only have so much room for these modifications before you need new parts.

I like to carefully look at the hammer hook angle and how it engages the sear. What I'm seeing in recent pistols is a very positive engagement angle. This is a safe angle but not necessarily the best for a smooth trigger and clean break. Current pistols seem to have about a 103 degree angle to the hook face. 90 degrees is considered ideal for a target pistol from my understanding but for safety reasons I keep mine at about 90.5 to 91 degrees. I don't have anything to measure any more accurately than that anyway. Unfortunately there are no tools made for the P22 like there are for other pistols so either a machine shop is required or some very slow and careful work here.

If you are doing the rear breech block mod you want to leave the bottom of the breech block its full thickness over the area where the retaining pin is located. Removing appx 0.20" from the bottom of the safety drum and rear of the breech block can make it where your hammer no longer drags on the bottom of the breech block/safety drum once cocked but....all of these modifications must be done in concert with each other. Too much off the hammer hook, the hammer now raises up too high before being caught and your work on the breech block is undone. Too much off the face of the hammer and it won't be pressed far enough rearward for the sear to engage the cock notch. The full cock notch must then be modified to restoring cocking or new parts ordered.

All of this works very nicely....but these are small parts and modifications to one part can affect the operation of other parts. Make sure you understand how these parts interact before doing any work on them. And, the sear-hammer hook engagement must hold the cocked hammer securely. M1911
 
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