Walther Rear Peep Won't Mount on Beeman R9

[Coues106]

I have an older Walther rear sight I was given recently and decided to mount on my Beeman R9. I don't know the specific model on the walther sight but it appears to be 11mm. I went to mount it, with the mount screw completely removed, and it slides on for the first inch or so, and then won't go any further. Would anyone be able to explain why this is the case? It seems pretty firmly set where it is and usable, I just don't know if it'll hold up to firing. I'm not sure if the proper approach is to rubber mallet it into place, or if I'm just overlooking something. Thank you!
 

[TorqueMaster]

I have no specific knowledge of the parts you are trying to fit together, but will toss out there that there exist both 3/8" dovetails (9.5mm) and 11mm dovetails, which sometimes cross-fit, and sometimes don't...

I think I had this problem in reverse once -- trying to fit an old scope/rings on a Daisy 3/8" rail -- they wouldn't squeeze down anywhere near close.

[Coues106]

There's a fair chance that's the issue, that it's a 3/8" sight on an 11mm rifle. That said, I have found the exact sight for sale on ebay, marked as 11mm. I can't post an external link, but on a Pyramydair article titled "Peep Sights: Part 2" it is the second sight pictured, billed as "walther's high-grade target peep". It is the same sight found on another article by Tom Gaylord on the Walther LGV Olympia, which I understand to have an 11mm dovetail. I might just go find the reloading calipers and give it a measure.
 

[Coues106]

Just as an update, I got it on being a bit more aggressive. It's an old sight that's been in a box of parts for a long time so the metal might have not been as springy or something. Either way, a bit of hoppe's no. 9 on the inside track, a small would handle of a brass brush at the base, and some rubber mallet tapping got it on snug. Thank you for the education on 3/8" vs. 11mm. Got me more confident that it was just a tight fit and not a wrong fit.   

[TorqueMaster]

Good news.  That peep isn't moving now.  I'm starting to wonder if someone as uninformed as I was at the time, tried too hard to make the peep fit a 3/8" rail, never got there, but left it slightly bent inward.   May or may not be possible on the peep.   My old 11mm scope rings were one piece and relied on flexing the metal legs to grip the rail.

[Coues106]

After taking it out and shooting it, I think it was the same 11mm as my Beeman R9, she just needed to be flexed after several decades of not being used. I put about 30 rounds downrange with it until it unscrewed itself and fell off, but some loctite on the threads have ensured we're good to go. Shoots like a dream and stacks cheap crosman premier's into the same hole at 10 yards. If I can ask another question, I have maxed out my adjustments on the rear sight and it's still shooting about 2" diagonal to the upper left from center. Is there any way to adjust the front sight on these for windage and/or elevation? Once again, the rifle is a beeman R9/weihrauch HW95.

[TorqueMaster]

If you don't get any replies here, you might re-post the question in the European Airgun Gate / German.  Be sure to specify the rear sight you are talking about -- the original or the Walther peep.

If it's the peep, I could see the elevation having issues, since a front and rear sight need to be "height compatible."  You may need a taller front sight.  Maybe one of those circular front sights with the swappable inserts.  But the windage on the peep should line up down the bore centerline and have plenty of adjustment both right and left.  If you can see that your front sight is visibly off-bore center, hopefully others more familiar can tell you how to move it.  If everything looks straight, and it's shooting off to one side, there may be a barrel issue.

I'm not a springer guy, but I do remember that scope rings and rails need to cleaned to be oil/grease free, and possibly pinned to the receiver, to prevent them from creeping along the rails. 

Hope this helps.

[MDriskill]

I'm sorry to be a downer, but that older Walther sight, originally made for their LG 55 and LGV rifles of the 50's through 70's, is NOT suited for mounting on your Weihrauch-built R9:

+ The mounting grooves are Walther's proprietary spacing of about 11.5mm, slightly wider than HW's 11mm rails (which size was standardized by Anschutz, Walther did this on purpose so Anschutz would not fit). FWB sights also use this odd spacing.
+ The "feet" of the mounting dovetail are at an oddball angle. Most sights use a 60-degree angle but Walthers are a bit steeper. You can damage the sight's or gun's rails by over-tightening.
+ The mounting crossbolt on the sight is intended to nest into a transverse groove across the gun's receiver, which locks it into one of three positions.

You can't slide the sight on because either the angle of the rails is binding, or the crossbolt is hitting the back face of the HW receiver (pic is a Walther LGV).

[MDriskill]

Here's the sight properly mounted on a Walther LG 55. Note the rifle has a spot-welded sight rail instead of cut dovetails, and a raised rear receiver end cap.

To mount the sight you turn the cross bolt all the way out; slide the sight on from the front of the rail (it won't go over the end cap from the rear); and carefully align the bolt with one of the transverse grooves before tightening it (a previous owner of this gun was not too careful with that last bit - note the resulting damage in my pic above).

[Coues106]

This is precisely what I was looking for, thank you. I had managed to get it on and hopefully without damaging the rifle or sight (nothing looks visibly amiss), but due to the differing dimensions and angles of the rail, I was only able to get it to stay attached to the gun for about 50 shots and then it simply fell off. It has since been replaced with a scope.

[MDriskill]

Thanks for the note - I'm glad the info was useful. The Walther guys worked hard to keep anyone else's stuff from fitting their guns!

Weihrauch made their own classic diopter back in the day - out of production, but they turn up. Old Anschutz sights work great too, I like to use those on mine.

[Hoosier Daddy]

Good info here.
Posting for future reference