Vintage Weihrauch 50 Fathers Day project

So, I acquired this Weihrauch 50 for Fathers day. At the time, I could see a couple of issues, but I didn't think they were a big deal. I was/am unfamiliar with the brand/ model, but who doesn't want a German gun?
I brought it home, dug out a box of. 177s & proceeded to get busy with it.
The front sight was loose, wedged in place with a piece of beer can hanging out the right side. I took it off , & stole a scope from a 760 that doesn't get shot much.
The breech seal most closely resembled old peanutbutter & may have been rubber at one time. A pair of o-rings will serve for now, a skinny one in the back as a spacer, & a fat one in front to seal.
From the 15 yard target off the back porch I was getting 5 shot groups that were easily covered with a pie plate.
After running through every different can of .177 pellets in the house, & discovering it didn't like any of them, I decided to open her up, & see what was going on in there.
First stop, the interwebs to see how this thing comes apart, & try to limit the surprises. 
Disassembly starts easily enough, & the first thing I noticed was that the two .006" pivot washers were missing. That might have something to do with those groups. 
The next thing I noticed was that the power plant didn't look anything at all like the videos I just watched. Confused, I go back to the interwebs & eventually determine that this gun has a HW50 front end, & a HW55 back end. It was the lack of a safety that led me there.
Disassembly can continue now, & it comes apart exactly as shown. The mainspring is well bent, & the piston cup is leather, & the grease has hardened to a solid mass. After agonizing over the cost, having the guy from Arizona not willing to even take my order, & not being able to make contact with anyone at pyramid, I ordered the whole kit from Vortek. It should be here in a few days. 
All the parts are cleaned, the piston is polished, it is quite undersize, so that was probably unnecessary.
1529470061_20335342305b29dc6d3f4de1.52423302_20180618_085948.jpg
1529470062_20692424225b29dc6ee32d04.86957812_20180618_085919.jpg
1529470064_1168898665b29dc70832334.50591270_20180618_085442.jpg
1529470066_20283357705b29dc72335028.08074050_20180618_084541.jpg
1529470067_4452756995b29dc73e53d55.86905370_20180618_084149.jpg
1529470069_11192938855b29dc75ba6605.59109935_20180618_083954.jpg
1529470071_18727515955b29dc7782f655.22875261_20180618_083923.jpg
1529470073_7324468575b29dc7945f3a5.26708023_20180618_083823.jpg
1529470074_15828542025b29dc7ad94a82.68630172_20180618_083739.jpg



 
Lots of WD40, paper towels, and the best part of a can of brake cleaner and I can finally see steel.
I think that I am most surprised by the general lack of finish on the interior steel parts of this gun. The trigger housing had a Burr on it that would cut you, not to mention scratching the trigger stamping. The cross at the end of the piston guide still had milling curlicues attached to it. The main stamping for the trigger was completely out of square. The piston assembly still had brazing scale on it, with so much heat applied it looked welded rather than brazed.
I straightened out the bent cocking lever guide, where it was rubbing on the cocking lever.
The inside looks like it was brake honed, or perhaps that's just the way it comes from the factory.
I didn't change the piston sear but I did deburr & polish it.
Also including a couple of pictures of my O ring breach seal assembly.
1529517975_21373915985b2a9797229bb0.39143213_20180620_131228.jpg
1529517976_16617655795b2a97987b4f75.77205080_20180620_131054.jpg
1529517978_1926317585b2a979a230618.71997050_20180620_130911.jpg
1529517979_12288988885b2a979bd74239.95254165_20180620_130838.jpg
1529517981_9968836795b2a979d8734c4.58526124_20180620_130813.jpg
1529517983_18284394905b2a979f39c1c3.70383349_20180620_130748.jpg
1529517984_15893620055b2a97a0e01bc4.96433035_20180620_130734.jpg
1529517986_542629975b2a97a2a124c2.36407339_20180620_130630.jpg
1529517988_12149706825b2a97a45ff594.94479808_20180620_130609.jpg
1529518373_10740614935b2a9925d1df45.40799591_20180620_131023.jpg
 
Congrats....Awesome Fathers day.
Looks like an early model based on the pre-Rekord trigger and no safety. Probably from the fifties. It also may not have pivot washers which are used on later models. If you don't mind, what is the serial number? I have seen soft material used, in lieu of leather, for sealing the breech. I suspect it's beeswax. Which would have been handy back in the day. Post a pic of the stock when you find time.

Steven
 
Hi Wadcutter, There was plenty of room to install the pivot shims. & I came up with the .006 number by sticking a feeler gauge in there, I think it was .013. Since the iron sights are just attached to the barrel, flop would not have made any difference, but it also has a long dovetail cut for a scope, or other rear sight.
Serial number is 326842, which, depending on which database I access, gives a date from 1955 to 1970. If anyone can do definitively better, please let me know.
My only provenance is I bought it from a guy at an auto shop yard sale in Wolfeboro, NH who said He got it from an auction.
I'm planning on a trigger post next, I will add pictures of the complete gun then.
 
Hi Wadcutter. You were so right about that Crown. I did some work to it and it has made all the difference.
I was just out in the backyard, Happily banging away at the 25 yd target, thinking that I might be just about done fooling with this thing, when all of a sudden the power dropped off and pellets started dropping about 4". This was from one shot to the next, not a gradual drop off. I will take it back apart and see what's going on.
1529971853_20110996975b31848d68e742.61107014_20180625_194010.jpg
1529971965_18930871045b3184fd55bff3.47063840_20180625_201220.jpg