am a beginner at tuning rifles...have both a 22 and 177 hw 97k. worked on the 22 first. Lots of videos, but none really complete, so learned some things the "hard" way. first, guns were so accurate I hesitated to work on them. not to worry, accuracy still there, even better. and Smooth. use a compressor, lots of "travel" on factory spring. trigger pins are TIGHT. lots of videos guys are taking them apart on their laps. not a good idea. I had a punch slip and marred the gun. I notched 2 pieces of hardwood to cradle the action, even drilled holes to accept the driven out pins. To ease reinstallation, taper the pins and use slave pins, 5/32. reinstalled trigger guard...just an empty hole for the rear screw...nobody said anything about the little nut on inside of housing. It's probably roaming around inside trigger housing, as I couldn't find it anywhere. so far no interference. watched for it on the 177, and sure enough, after all that pounding it was also floating around inside the housing. couldn't get it back into place, so didn't use it. factory did have grease on internals, but things still "sproingy". not anymore. great guns, am getting 25 yd one holers, and the holes are not much bigger than a single pellet. Also, the 22 kit had 3 washers, and I used them all, only to find the gun wouldn't cock. back apart and removed one, and ok. thought I'd share, maybe prevent others from some frustrations.
am a beginner at tuning rifles... reinstalled trigger guard...just an empty hole for the rear screw...nobody said anything about the little nut on inside of housing. It's probably roaming around inside trigger housing, as I couldn't find it anywhere. so far no interference. watched for it on the 177, and sure enough, after all that pounding it was also floating around inside the housing. couldn't get it back into place, so didn't use it... thought I'd share, maybe prevent others from some frustrations.
When it comes to the hex nut at the rear hole in the trigger, it's possible no one else mentioned it because some of the older HW rifles didn't even have it. Instead, the older housing had extra metal where the nut now goes, and it was folded and tapped to the same thread size as the nut (4 mm .7 metric). So, maybe their rifle didn't have one (this applies to several other models, too, like R1/HW80, R9/HW95, etc).
Anyway, at some point in time someone at the Weihrauch factory apparently realized that could be a problem if the threads in the housing ever stripped, so they modified the design of the trigger housing to accept and hold a standard 4 mm hex nut. That way if the threads got stripped, all you had to do was replace the nut, not the housing.
I keep a few of the nuts in stock in case I lose one on the floor somehow--granted, it's easy to do when you do the work, as you found out. My local Ace Hardware stocks the nuts.
If you don't put that nut back where it goes on your rifle, your rear trigger guard screw won't have anything to thread into, and you'll have to leave the screw out. I guess that's what you already found out. No--you're right, you sure wouldn't want to leave it bouncing around inside the rifle itself!
In any case, if you get a little more stubborn about it you should be able to get the nut to fit back into its original position, if you want to. Even if you leave the screw and nut out of the rifle, though, the other 3 larger stock screws will still give you a secure receiver-to-stock mounting arrangement. I just like to have all 4 screws how and where they originally came installed.
