GTA
Airguns by Make and Model => Diana Airguns => Topic started by: Bayman on February 10, 2022, 06:27:29 PM
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A friend sent me a Diana 27 to tune. It's a cool little gun that I would have loved to have as a 14 year old. I've never worked on one before. I test shot it with JSB 7.33 and it averaged 705 with a extreme spread of 12. I was under the impression these didn't run this strong. It was certainly dieseling mildly as confirmed by the orange haze in the barrel but it was well within acceptable levels.
I took it apart and the gun is in decent shape internally. Unfortunately the leather Sealed damaged by a deformation of the compression tube by the trigger prongs. The spring appears to be in good shape but the original steel guide is bent. The owner would like to replace the spring, seal and guide. I can't find an off the shelf kit for this gun does anyone have any suggestions or tips.
Thanks
Ron
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Blue Book says the Model 27 was discontinued back in 1987 so nope, no kit and a rifle you're gonna have to wing it on...lol.
Link to TW Chambers if you haven't been there yet: https://www.gunspares.co.uk/products/24376/27/ (https://www.gunspares.co.uk/products/24376/27/)
You might also try talking to Hector and see what he has for sources for older Diana parts.
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Hi Ron. I know these guys usually are good for vintage airguns: https://www.gunspares.co.uk/products/24376/27/ (https://www.gunspares.co.uk/products/24376/27/) . Maybe also check with Baker Airguns or Precision Pellets?
Good luck in your search!
Also, if ever you had the opportunity/possibility, would you be kind enough to measure the piston stroke on that gun? I have an old chinese break barrel that I think is a clone of the D27, would like to get as much specs as I can for comparison. TIA.
Btw, which trigger does it have?
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Thanks guys. Chambers is my go. They have the piston seal but not the spring. I could use a larger diameter Hw30 spring but it's not long enough in stock form. I already talked to Tom at Vortek and he has cut to length springs that should work. "Should" being the key word. The cocking arm already rubs on the spring on barrel closing. Not sure if this is as much to do with the bent steel guide as the available clearance. Increasing the diameter of the spring would likely aggravate the issue. Re-engineering parts can start a long string of unforeseen challenges. This should be fun.
As far as the trigger goes. I have no idea what type trigger it is. It has three balls that hold the piston stem and the trigger uncovers them simultaneously to release the piston. Dianas are a new adventure for me.
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As far as the trigger goes. I have no idea what type trigger it is. It has three balls that hold the piston stem and the trigger uncovers them simultaneously to release the piston. Dianas are a new adventure for me.
Reminds me of the T01 trigger: https://www.tapatalk.com/groups/yellow/diana-48-52-t01-trigger-disassembly-assembly-pictu-t141998.html (https://www.tapatalk.com/groups/yellow/diana-48-52-t01-trigger-disassembly-assembly-pictu-t141998.html)
The one that shows on the Chambers diagram I think 8).
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I bookmarked this site a long while ago, now I know why.
https://www.jgairguns.biz/27-c-78_247_255/ (https://www.jgairguns.biz/27-c-78_247_255/)
They mention a Titan spring. Hector knows Titan Springs. ;)
-Y
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The only three-ball Diana trigger that I am aware of is the TO1.
Sounds like you've already been into it to discover the three balls.
I have a 20+ pic dis- and re-assembly procedure should you require it. They're not fun to work on.
The TO1 was the very first trigger I ever overhauled.
:D
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Diana used a type of three-ball trigger already before the T01.
I have a c. 1960 D25. I'm not sure how the D27 differs from this youth rifle. The D25 came either with a simple, direct-sear trigger or a three-ball configuration (not in 1960, though AFAIK). The latter is highly regarded still. Mine has the simple trigger, which isn't a fine trigger by any measure.
I got the seals and the mainspring for the gun from Chambers, a couple years back.
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Thanks guys. Chambers is my go. They have the piston seal but not the spring. I could use a larger diameter Hw30 spring but it's not long enough in stock form. I already talked to Tom at Vortek and he has cut to length springs that should work. "Should" being the key word. The cocking arm already rubs on the spring on barrel closing. Not sure if this is as much to do with the bent steel guide as the available clearance. Increasing the diameter of the spring would likely aggravate the issue. Re-engineering parts can start a long string of unforeseen challenges. This should be fun.
As far as the trigger goes. I have no idea what type trigger it is. It has three balls that hold the piston stem and the trigger uncovers them simultaneously to release the piston. Dianas are a new adventure for me.
ARH lists a spring for the Diana 27:
https://www.airrifleheadquarters.com/catalog/item/251488/4452198.htm (https://www.airrifleheadquarters.com/catalog/item/251488/4452198.htm)
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When the trigger is adjusted right it is a sweet trigger. You have to find that sweet spot. Like an FWB 124 if you know what I mean. You have to be in the ball park first. I haven't done one lately. Mine is well adjusted crisp no creep (same as my 124). I should be able to help if you need when that time comes.
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It's NOT a "T01!"
The 27 has the classic original "ball-sear" trigger. This trigger was used in the models 25D, 27, 35, and 50 for more than 3 decades, beginning about 1951. With eight model 27's in my house, I've been forced to come to terms with it over the years! The operating principle is the same as the T01 (which did not exist until the model 34 and its relatives came out about 1984}, but execution is completely different.
With the ball-sear, the operating parts are NOT contained in a surrounding sleeve as in the T01, but will all come out separately when you remove them from the gun. It's really easy to work on - no safety which helps things stay simple - but you gotta have a bit of foreknowlege.
Here is an old thread I did that shows the basic workings:
https://www.airgunnation.com/topic/winchester-425-trigger/ (https://www.airgunnation.com/topic/winchester-425-trigger/)
NOTE - the spring guide is part of the trigger! Its rear flange edge forms the stop for the outer "sleeve" of the mechanism.
My experience is that the leather piston seals and mainsprings in these old Dianas are of very high quality, and will last a really long time. Note that if you remove the piston seal, its main attachment screw is staked to the piston with a small "blind" pin; you will have to turn the screw with enough force to shear the pin.
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Thanks everyone. This is a great place to seek help from knowledgeable people.
Based on pictures this isn't a T01 trigger. The trigger itself feels nice. It's a little heavier than I'm used to but I don't think I'd mess with it, other than a clean, lube and possibly a polish.
I looked into the maccarri spring. It's a square wire spring and I'm not sure I'm comfortable with that.
The piston seal and adapter I'm getting from Tom at Vortek. Possibly the spring too once I work out what I need for dimensions to alow for a reliable spring guide construction.
As far Measuring the stroke. I will try but it might not be easy or immediate. I have to install the piston and trigger balls and measure the distance between the two. I may not have the seal for a while as I need time to sort out the spring sizing.
Thanks again everyone for the help and suggestions. I'm enjoying this
Thanks Mike I just seen your post after I finished the section above. I figured out about the guide/trigger interface already. I could see how that would be easily overlooked. I was hoping to hear from you. You're the most knowledgeable person I know when it comes to older airguns. And possibly certain plastic aviation subjects ;)
Be well Mike D
Ron
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Thanks Ron...dunno what yer talking about on the airplane thing though LOL...
At the risk of sounding like I'm bragging on myself, do read the whole thread that I linked above. There is some back-and-forth with the thread's OP that discuss variations of the ball-sear design over time, and helped me learn some new tricks for working on the things (yours looks like the last variant, which has advantages).
I've never tried this myself, but a friend has had great luck using, IIRC, Maccari's "Merlin" spring in the model 27.
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It's NOT a "T01!"
The 27 has the classic original "ball-sear" trigger. This trigger was used in the models 25D, 27, 35, and 50 for more than 3 decades, beginning about 1951. With eight model 27's in my house, I've been forced to come to terms with it over the years! The operating principle is the same as the T01 (which did not exist until the model 34 and its relatives came out about 1984}, but execution is completely different.
With the ball-sear, the operating parts are NOT contained in a surrounding sleeve as in the T01, but will all come out separately when you remove them from the gun. It's really easy to work on - no safety which helps things stay simple - but you gotta have a bit of foreknowlege.
Here is an old thread I did that shows the basic workings:
https://www.airgunnation.com/topic/winchester-425-trigger/ (https://www.airgunnation.com/topic/winchester-425-trigger/)
NOTE - the spring guide is part of the trigger! Its rear flange edge forms the stop for the outer "sleeve" of the mechanism.
My experience is that the leather piston seals and mainsprings in these old Dianas are of very high quality, and will last a really long time. Note that if you remove the piston seal, its main attachment screw is staked to the piston with a small "blind" pin; you will have to turn the screw with enough force to shear the pin.
Thanks also to you Mike for the info on the early three-ball trigger. I did not know that there was an earlier version.
My only experience with a three-ball was when I did my very first rebuild of an early '90's D34 Jubilaum, TO1 trigger. I was actually able the restore the original leather seal, as I have subsequently done on many of my early year Weihrauch. As I remember, you helped me out immensely on that D34 rebuild, and that was in my dinosaur years of learning about airguns (about four or five years ago I think).
That was when I first "met" you via this forum.
That Jubilaum D34 is still one my most comfortable and most accurate shooters. I'll have to dig it out and shoot it more this next season.
As Bayman said, I also consider you to be the most knowledgeable regarding vintage airguns.
And, as we once discussed back in those years, you are also an excellent plastic aircraft modeler. I've never seen those type of stripes on the prop of an FW190. What version is that?
Dennis :D
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Dennis, thanks for the kind words! I describe my airgun knowledge as "narrow but deep," LOL. I know very little about the vast majority of guns out there, but I do have a few faves I wring out pretty well. The D27 is on that list.
The model is a 1/72 scale WW2 Focke-Wulf Fw 190A-8. Most German fighters had a white spiral on the prop spinner, and in late 1944, Jagdgeschwader 1 - a unit with a history of colorful markings - had a few 190's with it pushed out on to the prop blades like this.
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There is a seller on eBay UK that sells Diana 27 springs. Ships to US. Go on on eBay and search "Diana 27 spring" It comes up under international sellers. I think they're NOS.
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There is a seller on eBay UK that sells Diana 27 springs. Ships to US. Go on on eBay and search "Diana 27 spring" It comes up under international sellers. I think they're NOS.
Thank you Karl for that information. I will have a look and consideration my options.
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I have a 1985 .177 D27 tuned by John in PA.
He recorded 720 fps, es 6, with JSB 7.87 when it was fresh, but it's lost about 30 fps over the years. Even still, I think the gun feels little jumpy for its weight and I wouldn't want it any hotter.
Have fun!
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I have a 1985 .177 D27 tuned by John in PA.
He recorded 720 fps, es 6, with JSB 7.87 when it was fresh, but it's lost about 30 fps over the years. Even still, I think the gun feels little jumpy for its weight and I wouldn't want it any hotter.
Have fun!
Thanks Dan for velocity readings. Yours is considerably hotter than this one, given that it's the same velocity with a heavier pellet and some of my velocity was dieseling enhanced. Any idea what a non tuned D27 shoots?
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Well...let's just see what the old guy can find in his musty folder of chrono work, lol.
Numbers below all from a Chrony Alpha, and are averages of 15-shot strings: pellet name and weight (grains); average velocity (FPS); extreme deviation (FPS); standard deviation (% of average velocity).
1. Prewar quarter-stock model 27, .177, made 09 26, interior condition unknown.*
RWS Hobby 6.9, 624, 11, 0.55
JSB Match Pistol 7.6, 589, 11, 0.61
2. RWS 27, .177, made 02 81. Never been opened, just basic maintenance.
1988
Eley Wasp 7.2, 677, 15, 0.54
RWS Hobby 7.0, 667, 34, 1.43
RWS Superpoint 8.0, 630, 34, 1.30
RWS Meisterkugeln 8.4, 618, 16, 0.81
1991
RWS Hobby 7.0, 676, 32, 1.01
Crosman Pointed 7.9, 619, 25, 1.20
1995
Ruko Match 7.5, 654, 13, 0.65
2007
JSB Express 7.9, 615, 16, 0.84
3. Winchester 427 no. 1, .22, made 02 73. Probably never opened up.
RWS Hobby 11.9, 521, 23, 1.12
4. Winchester 427 no. 2, .22, made 10 73. Very smooth tune from previous owner.
RWS Hobby 11.9, 499, 28, 1.73
Just an editorial note, an SD under 1% is springer match gun territory. The consistency that model 27's get says a lot about the quality of Diana's springs and seals in the old days.
* The power and consistency of this ancient rifle are amazing. The thing shoots so smoothly, I would have guessed the power was in the 400's...!
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Well...let's just see what the old guy can find in his musty folder of chrono work, lol.
Numbers below all from a Chrony Alpha, and are averages of 15-shot strings: pellet name and weight (grains); average velocity (FPS); extreme deviation (FPS); standard deviation (% of average velocity).
1. Prewar quarter-stock model 27, .177, made 09 26, interior condition unknown.*
RWS Hobby 6.9, 624, 11, 0.55
JSB Match Pistol 7.6, 589, 11, 0.61
2. RWS 27, .177, made 02 81. Never been opened, just basic maintenance.
1988
Eley Wasp 7.2, 677, 15, 0.54
RWS Hobby 7.0, 667, 34, 1.43
RWS Superpoint 8.0, 630, 34, 1.30
RWS Meisterkugeln 8.4, 618, 16, 0.81
1991
RWS Hobby 7.0, 676, 32, 1.01
Crosman Pointed 7.9, 619, 25, 1.20
1995
Ruko Match 7.5, 654, 13, 0.65
2007
JSB Express 7.9, 615, 16, 0.84
3. Winchester 427 no. 1, .22, made 02 73. Probably never opened up.
RWS Hobby 11.9, 521, 23, 1.12
4. Winchester 427 no. 2, .22, made 10 73. Very smooth tune from previous owner.
RWS Hobby 11.9, 499, 28, 1.73
Just an editorial note, an SD under 1% is springer match gun territory. The consistency that model 27's get says a lot about the quality of Diana's springs and seals in the old days.
* The power and consistency of this ancient rifle are amazing. The thing shoots so smoothly, I would have guessed the power was in the 400's...!
Thank you Mike!
That's all great useful information. I was surprised at the power and consistency of this gun on my initial test. After 2 shots to check for function I chronographed the next 10 and I believe the ES was like 8. Not bad for an old dieseling gun with a leather seal. It's really a nice little gun. Well other than it cocks like a marble grinder and the cocking arm skips over every coil on closing. I think that's because of the bent steel spring guide. I'm gonna have to come up with a fix for that by figuring out a spring that's the right rate and length while leaving enough room for a new guide that will work with the trigger and still clear the cocking arm. Fun :)
Also I bookmarked that fantastic thread where you go over the triggers so thoroughly. I will refer to it when I get to that point. Today I'm going to sort through my spring options and order the seal.Thanks for all your help. MUCH APPRECIATED
Have a great day
Ron
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I would talk to the owner about keeping the same spring; good FPS and old times quality.
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I would talk to the owner about keeping the same spring; good FPS and old times quality.
Thanks, I have and it's an option. I'd prefer to refresh the spring with one with zero shot count and would allow room for a better guide design. If not possible I'll work with the factory spring and make the best of it. Both the owner and I'm open to hearing about plausible solutions. I will send back a quiet and smooth gun regardless of the necessary path to it.
Thanks for your input.
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Just to let you know, I had a very bad experience with a Titan spring for my Diana 350. Although I bought the suggested model for the 350, it simply didn't fit. With the OEM spring sleeve, impossible. Even without the sleeve, a VERY bad scratch all way long when cocking. Btw, the FPS was about the same as the OEM springs. Useless.
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Just to let you know, I had a very bad experience with a Titan spring for my Diana 350. Although I bought the suggested model for the 350, it simply didn't fit. With the OEM spring sleeve, impossible. Even without the sleeve, a VERY bad scratch all way long when cocking. Btw, the FPS was about the same as the OEM springs. Useless.
Thank you Marcus, well noted. AoA substituted a titan spring for my Hw30 and it wasn't even close to right. I'm not sure who was at fault there.
On this gun I decided to use a cut to length Vortek spring that's similar in size to the original. I'm gonna have a custom fitted steel guide and a delrin top hat made for it.
Using the factory spring wasn't an option after I seen the pitting and longitudinal wearing on it. I only noticed it today after the wash tank.
Also note the bent OE rolled steel spring guide. I believe that's what was causing all the problems.
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British airgunners who have tons of experience with their native Titan springs tell that the only thing consistent with the Titan spring measurements is the length. Their fit in particular airgun models is to be considered as mere suggestions. Some springs are too large in OD to fit inside the piston of a gun that it was sold for. Often times a Titan spring works well in a gun that was NOT mentioned in the product info.
That being said, Titan springs shoot hard and are extremely long-lived. By the time a Titan-springed gun starts to show fatigue, you most likely have replaced the OEM or Vortek spring a half-dozen times or more. That's huge in my book, as it's not only the spring cost and the assembly time, but the break-in of a new spring that adds up.
ETA: the fact that the Titan shot about the same as an OEM spring in a 350 Mag is just what is to be expected. The Titan was never sold as a power-booster, and Diana OEM springs shoot hard, anyway. They just don't last near as long.
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British airgunners who have tons of experience with their native Titan springs tell that the only thing consistent with the Titan spring measurements is the length. Their fit in particular airgun models is to be considered as mere suggestions. Some springs are too large in OD to fit inside the piston of a gun that it was sold for. Often times a Titan spring works well in a gun that was NOT mentioned in the product info.
That being said, Titan springs shoot hard and are extremely long-lived. By the time a Titan-springed gun starts to show fatigue, you most likely have replaced the OEM or Vortek spring a half-dozen times or more. That's huge in my book, as it's not only the spring cost and the assembly time, but the break-in of a new spring that adds up.
ETA: the fact that the Titan shot about the same as an OEM spring in a 350 Mag is just what is to be expected. The Titan was never sold as a power-booster, and Diana OEM springs shoot hard, anyway. They just don't last near as long.
Thank you Duke. That's good useful information. It's a shame that the Titan spring sizing is off, because it makes it cost prohibitive for guy like me to try them.
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Hi Ron. I know these guys usually are good for vintage airguns: https://www.gunspares.co.uk/products/24376/27/ (https://www.gunspares.co.uk/products/24376/27/) . Maybe also check with Baker Airguns or Precision Pellets?
Good luck in your search!
Also, if ever you had the opportunity/possibility, would you be kind enough to measure the piston stroke on that gun? I have an old chinese break barrel that I think is a clone of the D27, would like to get as much specs as I can for comparison. TIA.
Btw, which trigger does it have?
I measured the stroke its just under 71mm with a synthetic replacement seal. 71 is an odd number I imagine it might be an even 70mm with the original leather seal..
I'm not sure of the trigger designation but it's a three ball design with a metal blade and two adjuster screws. I cleaned, polished and lubed the contact points. Flipped the wear plate and adjusted it. It's a two stage trigger that's heavier, with more second stage travel than my Rekords but it's quite smooth and predictable. It's actually a nice trigger, IMO.
When all is said and done, I think it's a cool little gun.
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Do you have it back up and running Ron?
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Do you have it back up and running Ron?
Yep and running great. I'm shipping it out to the owner tomorrow.
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Also, if ever you had the opportunity/possibility, would you be kind enough to measure the piston stroke on that gun? I have an old chinese break barrel that I think is a clone of the D27, would like to get as much specs as I can for comparison. TIA.
I measured the stroke its just under 71mm with a synthetic replacement seal. 71 is an odd number I imagine it might be an even 70mm with the original leather seal..
Ron thanks so much! I also installed a synthetic seal in my rifle and I get the same exact stroke measurement. I guess I can now say I have a vintage China-made clone of a Diana 27 lol!
Hope your customer will enjoy this fine piece of an airgun!
Cheers, Francois
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Also, if ever you had the opportunity/possibility, would you be kind enough to measure the piston stroke on that gun? I have an old chinese break barrel that I think is a clone of the D27, would like to get as much specs as I can for comparison. TIA.
I measured the stroke its just under 71mm with a synthetic replacement seal. 71 is an odd number I imagine it might be an even 70mm with the original leather seal..
Ron thanks so much! I also installed a synthetic seal in my rifle and I get the same exact stroke measurement. I guess I can now say I have a vintage China-made clone of a Diana 27 lol!
Hope your customer will enjoy this fine piece of an airgun!
Cheers, Francois
Cheers buddy. I'm glad to be of help.
Be well
Ron
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Big shout out to Ron for getting my Diana 27 back to me functioning better than when it left the factory. Shot cycle is a thump instead of the twangy self it was. He smoothed the trigger to a light and crisp release. Absolutely great guy to do business with and I really liked how he kept me informed during the rebuild. Thank you Ron!!
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I currently have a Diana27....BEAUTIFUL gun, and great shooter!
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I currently have a Diana27....BEAUTIFUL gun, and great shooter!
Hey Lizzie! :) How are you? Long time no hear :(
Text me if you prefer.
Be well ttys
Ron
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Hi Ron! I will text--- sorry it's been so long, I have just been busy with work, because since the pandemic started, staffing has become almost impossible to cover, and I have more work than I want. Haha...
Now that you are delving into Dianas, I have a model 45 that needs a tune, whenever you have the time. Let me know! :-*