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Beware: MK III 22/45 Reassembly Mistakes

I had to break down my 22/45 for cleaning (it was stove piping and misfeeding like crazy after I got into a new box of Auto Match) and I ran into two issues that could go unnoticed but still cause function issues during live fire.

The first problem was more obvious to detect. Upon reassembly the bolt would not lock back on an empty magazine. The bolt catch clicked audibly when moved but was too stiff for the magazine to actuate it. The safety, on the other hand, was easy to move. Turns out I'd swapped the detent springs between the two, so make sure you use the soft spring in the bolt catch and the harder spring in the safety. The safety should click with around 2x the force of the bolt catch.

Then when I brought it to the range, I didn't get any misfeeds but every now and then I'd have a dead trigger after firing, and have to force the trigger forward to reset the sear. I thought this might be due to my pretravel screw being turned too far in (I have a TK Victory trigger) but it turns out the trigger pin was moving within the frame, causing enough slop that the sear wasn't resetting when the trigger was allowed to move forward.

The reason why became obvious upon disassembly; I'd swapped the hammer pin and the trigger pin. They both have grooves to retain the leg of a spring but one has another identifying line between the spring groove and the end of the pin - this one is the trigger pin.

It's a good idea to keep all the parts and pins for the hammer/safety, trigger/mag release, and sear systems separate which will minimize the likelihood of these problems occurring.

One other tip during reassembly; when inserting the sear, try putting the sear in first, inserting the sear pin from the opposite side of the sear spring slot to catch it in the frame, then dropping in the sear spring. I found this a lot easier than trying to insert the sear spring then the sear itself as the legs of the sear spring kept getting in the way or causing it to pop out of the slot.