Diana D75 sight saga

[jccams]

I have a very nice D75S T01 mfg 91 lefty that is very healthy and accurate. I bought it with a centra Duo front sight and a nice Gehmann rear sight setup. Problem is front sight is 11mm, dovetail is 9mm. I was able to resolve with a 1mm pin. Today I realized the rear sight is a 13mm dovetail, obviously not centered on an 11mm dovetail, although secure. Not sure the seller ever shot it with these sights. So I had purchased a T01 rear sight as the seller couldn't find the original. Since I have the OEM front sight I decided to put the T01 on it, so I could at least shoot it. Nope the sight won't slide on the dovetail. What am I missing, T01 gun, T01 marked sight. Frustrating having such a nice gun that I can't shoot. Any advice welcome. Looks like I'll be selling these nice sights.

Update: As a longshot I contacted the seller to see if he could find the original rear sight. He replied that he had found it and is going to send it to me. Be interesting to see what it is.

 

[marflow 777]

show me the front sight
the same front sight would have been used on the Model 65-66 and 100
you say it will not fit because it is too tight or too small

 

[jccams]

show me the front sight
the same front sight would have been used on the Model 65-66 and 100
you say it will not fit because it is too tight or too small

This is the rear sight that won't fit. The seller is sending the original sight. I'll post pictures of the sight that won't fit.
Here's the OEM front sight with a Gehmann adjustable iris. It looks like it takes a metal insert, I have the insert retainer for the sight. What would I look for for inserts?

Here is the dovetail on the gun and the sight I cannot get to slide on.

 

[Chuck-in-Ohio]

You did loosen the clamping foot on the sight before trying to install it correct?

 

[marflow 777]

so, the diopter is correct and the rifle and the sight should just slide together
start it at the front of the mount it is easier and if the front of the sight is damaged from use it will start where it is not
they are a tight fit
i cannot see if the diopter rails have been damaged over time, it does show a lot of use

 

[Motorhead]

Odd ... My 75 HV ( Which did come with 2 front sight assemblies ) are cast as a one piece unit, tho do take screw in inserts etc .
Whats odd is I can't recall seeing a front hood sight that dovetail mounts as your showing on original D75's ?

Pics are the "High" and low looks identical just lower

 

[marflow 777]

but an HV is not a TO1 rifle it has a tall front sight

 

[Chuck-in-Ohio]

Odd ... My 75 HV ( Which did come with 2 front sight assemblies ) are cast as a one piece unit, tho do take screw in inserts etc .
Whats odd is I can't recall seeing a front hood sight that dovetail mounts as your showing on original D75's ?

Pics are the "High" and low looks identical just lower

View attachment 498216

View attachment 498218

Scroll down the page and you will see pics of the same set up as his rifle.

https://forum.vintageairgunsgallery.com/post-war-diana-air-rifles/diana-model-75/

 

[jccams]

You did loosen the clamping foot on the sight before trying to install it correct?

Can't even get it to start sliding on.

so, the diopter is correct and the rifle and the sight should just slide together
start it at the front of the mount it is easier and if the front of the sight is damaged from use it will start where it is not
they are a tight fit
i cannot see if the diopter rails have been damaged over time, it does show a lot of use

Didn't realize it was such a tight fit, I'll try again.

 

[Bear-of-Grayling]

The diopter is a VERY tight fit on the 75. You have to hold your mouth just right to get it on.

 

[zrman27500]

I'd love to buy that t01 sight from you if you decide to sell.....pm me if you do!

 

[jccams]

I'd love to buy that t01 sight from you if you decide to sell.....pm me if you do!

Once I get the original it will be for sale.

 

[zrman27500]

Once I get the original it will be for sale.

Well send me a message if/when you are ready, we will see If we can come to a deal.

 

[zrman27500]

I was just thinking that those hv rifles had a special riser block for the rear sight, I wonder if the dovetail is slightly different on a hv rifle to accommodate the riser block? Or possibly your dovetail or the sights dovetail has a burr on it or something.....the sight does look a little beat up on the bottom.

 

[Motorhead]

I was just thinking that those hv rifles had a special riser block for the rear sight, I wonder if the dovetail is slightly different on a hv rifle to accommodate the riser block? Or possibly your dovetail or the sights dovetail has a burr on it or something.....the sight does look a little beat up on the bottom.

Having an HV and having worked on many others over the years, the rear base dovetail is the same on all from what I've seen. There is a Riser plate that fits base for the HV application having rear sight on a taller plane.
The front on the ( My ) HV is a complete housing replacement where you just change over the guts of the sighting parts between Low and HV height housings.

 

[zrman27500]

Having an HV and having worked on many others over the years, the rear base dovetail is the same on all from what I've seen. There is a Riser plate that fits base for the HV application having rear sight on a taller plane.
The front on the ( My ) HV is a complete housing replacement where you just change over the guts of the sighting parts between Low and HV height housings.

View attachment 498731

Well that answers that question! I just wasn't sure if that was a possibility considering he can't get the correct t01 sight to fit on there.....it's gotta have a burr in the rail of the rifle, or the sight not allowing it so slide on. I can't think of anything else it would be.

 

[jccams]

Update: I received the original rear sight today. This gun is a 91 mfg, the sight is a model 100 and it slid right on. Not sure the T01 sight is compatible. I have a T01 riser and the T01 sight slid right on that. Anyway I am a happy camper now that the gun is back to original. I am guessing at some point later in the production Diana switched to the 100 sight. The gun is marked T01. I saw a 92 mfg that also had the 100 sight on it.

 

[MDriskill]

Thanks, that's very interesting. I wonder if Diana again changed the rail design when they went to the model 100 sight?

 

[jccams]

Thanks for chiming in Mike, your knowledge and insight is always appreciated. This weekend I'll get the gun out and compare the T01 to the 100 sight. I'll also try and slide the T01 riser on the dovetail, at least I'll be able to see what's going on. The T01 sight doesn't allow you to see why it is not going on. I'll take some pictures of the rail too. I'm actually happy with the 100 sight, I think I can install a Gehmann adjustable iris. Can't wait to shoot it with its original sights.

 

[marflow 777]

no the model 100 and model 82 were both just upgrades to the model 75 TO1 sight, both are 20 click sights and both are clamp on like a Anschutz sight would be
now at some point, were the 100 being installed because the model 75 TO1 sight was no longer available that could be
but his rifle was dated 1991 and the S model was discontinued in 1999+
but maybe the S model came with the upgraded sight and the B model did not i would have to do some looking
so, it looks like when the model 100 rifle came out in the 1989 that the Two model 75's the S and B got model 100 diopters
you can see that the diopter 100 came with two different sunshades short and long
there is a curious connection between the S model and Model 100 rifle stock they both n=have a black plastic cap in the grip area

i would like to see the TO1 sight he has and would fix it if i could , there is no reason other than damage it will not go on