GTA
All Springer/NP/PCP Air Gun Discussion General => European/Asian Air Gun Gates => German AirGun Gate => Topic started by: Toxylon on October 02, 2022, 05:38:40 PM
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Back in the ’80’s I used to see full-page magazine ads for Diana and Daisy airguns. The springers in these ads were brightly colored, red, white, blue etc., and clearly aimed at a new audience. The Dianas were way too expensive for me to even consider back then. To my young, ignorant mind, “Diana” didn’t even sound like a cool gun name, and the preppy colors didn’t exactly help the image.
A couple days ago I stumbled upon a for sale ad for just such an 80’s Diana: a bright blue Diana Sport .177 cal. These guns seem close to absent online, not helped by the extremely generic name, and the only usable hits came via a couple of image results for the same series guns for sale on auction sites etc. The photos showed the Diana Sports were stamped as D34’s, and as far as I could tell, different from ordinary D34’s only in the painted stocks.
I bought the Sport for a small sum, having little data on it, and no chance of seeing the gun in person pre-purchase. All I had was a single photo of a somewhat beat up 80’s gun with visible rust, and the seller’s comment on how the gun dated from around 1988 to 1990, was much used by the seller for a couple of years as a kid, and had spent the last several decades in storage (cold, I might add).
The gun arrived a couple of days ago. It clearly was a D34, by looks, measurements, and the stamp on the receiver. While the “Made in West Germany” stamp placed the gun instantly to the 1980’s, the manufacturing date was impossible to decifer down to a year due to corrosion. Being an early D34, the year mattered quite a bit, as far as gun specs and details go.
The gun was rustier indeed than I had hoped. Every steel nook and crevice had more or less orange hues present, and the barrel was actually pitted, so the first thing out of the box was to wipe the gun down with Ballistol. 0000 steel wool, soaked in the same stuff, followed.
With the restorative measures the tiny date stamp became legible: 12 / 88. So, this gun was three months shy of being just as old as the model name: 34 years.
The paint finish on the wood stock had innumerable small scratches, dents and some missing bits of paint. This was all expected, for a 34-year old gun that had seen heavy use by a school boy long ago.
Looking through the barrel I was half expecting evidence of small pebbles and finishing nails having been used as ammo, but no: the rifling looked fine. An ancient half-empty tin of RWS Meisterkugeln 8.2 gr. pellets that came with the gun showed the Sport had been fed quality ammo. Pulling a bunch of batches, wet and dry, produced pitch black rings on the patches, but the barrel got better in a hurry.
I was surprised to find an empty hole in place of the safety in this T01 gun. Someone had clearly considered it a nuisance.
As far as I knew, the Diana had decades old seals and lubes and as such, was not really in a shootable condition. But as the outside soaked a little oil, and tentative ¾ cocking strokes didn’t ring an alarm, I put the old lady to a small test.
I whipped up the chrono and put some R10 Match 8.2 gr. pellets through the Diana. The gun had an extremely low cocking effort, almost at two-finger level. Even with that in mind, the velocity readings were very low: around 127 m/s / 417 fps, for under 5J / 3.5 fpe ME.
I had kinda wondered how the seller, at age 10 back in the late ‘80’s, could shoot a whole bunch with an adult-sized, hunting power springer, which a D34 is. Here was the answer. I didn’t think the extremely easy cocking stroke was only due to old age, I thought it was deliberate.
More to come.
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A couple more photos at this juncture (the attachment size limit per post is just so low).
The rear sight is a Franken-one, having some original parts and much that is not. Too bad, as I would've liked to see how well put together the 80's Diana factory sights were, compared to today's Walmart quality.
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I started investigating the reasons for the “weak even by German specs” level performance. (BTW, there is no “F” pentagon stamp anywhere on the gun).
Taking out the spring-retaining pins in the receiver butt, the trigger block didn’t move anywhere, as it should from the mainspring tension. I actually had to take the receiver out of the spring compressor and gently pound the block out, inch by inch, using a rubber head hammer.
A black plastic rear guide, of the standard Diana type if not for color, came off the exposed mainspring rear all too easily. But the mainspring itself was curiously stuck: I had to really pull to get the spring out, when at this stage it should take effort to keep the spring from falling out.
The mainspring was drastically short, at 224mm about three inches under an OEM spring length. The spring was also snaky from canting, indicating the non-closet-queenness of this gun. Reasons for the low power were coming in fast.
The upper end of the short spring was completely unfinished and looked almost like the spring had sheared in two at this joint (see pic 1). Was there a section of the mainspring still inside the piston? Nothing there.
Had the mainspring been crudely cut and left unfinished at some point in the gun’s history? The lower end of the spring was appropriately collapsed, ground and leveled.
Getting down to the piston proved yet another stuck experience; the piston didn’t move inch by inch, but millimeter by millimeter, using substantial force on the piston’s cocking slot. It started to look like a miracle the gun did fire at all.
When the piston did emerge, it was covered partly in factory grease, partly in caked-up moly (see pic 2). Even the piston seal face was silvery with moly contamination. The reason for the lube bleeding was the substantial damage the seal perimeter had received at installation, not unlike on my 2015 350 Mag (see pic 3).
The piston seal had an OD of 28.6mm, which is the very oversized diameter Diana seals come off the factory. In my experience, the OEM seals at these diameters cut velocity by hundreds of fps, before being sized. To imagine this level of piston resistance in a 5J gun...
Pic 1: sheared / cut mainspring end after cleaning it up
Pic 2: piston front and seal straight out of the chamber
Pic 3: piston seal damage on the cleaned seal
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I degreased the receiver and the piston thoroughly and deburred the slots in both. To keep fighting the ever-present corrosion (see pic) I then immediately wiped the receiver exterior with a fresh coat of Ballistol.
I had an almost-unused CAS seal for the 28mm Dianas that had proved a lousy match for the power level of my 350 Mag. But the Brits, with their 12 fpe limit, think very highly of these seals. This mid-power .177 cal might fit the soft-material seal better, and the seal was already of the correct size. So, on it went.
The breech seal was visibly flattened, from 30 years of being squeezed tight against steel. I did perform the tissue test when chronoing the unopened gun, which indicated the seal did seal just fine. Still, I changed the O-ring to a fresh, plump one, keeping the 0.2mm breech seal shim that was present in the gun from the factory.
Neither the piston seal nor the breech seal showed any signs of hardening up or turning brittle, even after all this time, which I found interesting.
I lubed the cleaned piston with a tiny amount of Ultimox on the front and rear bearing surfaces of the piston plus on the sides of the new piston seal.
The ancient mainspring was a crippled geezer by any measure, but just for giggles I put it in again, with the freshened up piston.
Putting the Sport back together I hit an unexpected bump: with the D34 having a one-piece cocking arm, I learned it was impossible to attach the barrel to the receiver with the powerplant already packed in, unlike on every other breakbarrel gun I have. My spring compressor would not allow hitching the receiver with the barrel on, as the D34 breech block front has almost no gripping surface.
Reading up on my options here, I chose to temporarily pivot joint the barrel using an undersized, over-long temporary pivot bolt (a lenght of 6mm steel rod) to cock the gun, take the barrel off and reattach it properly with the spring tension out of the picture. Phew! Another McGyverish experience added to my belt.
Taking a few chrono shots with the admittedly all-too-fresh tune showed 185 m/s and 9,1J, or 607 fps and 6.7 fpe with the R10’s – a nifty 100 % increase in ME, from a basic clean, deburr, reseal, relube scenario!
Still far from the power level of a healthy D34, the obvious next step was to find and fit a new mainspring.
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Been interesting to read this. I just acquired a new classic D34 and immediately opened it to find a nicked seal so after deburring, I too did a CAS seal with an ARH GRT tune kit. Its been fantastic. I've found the CAS magenta seals (like you pictured) to be quite stiff and have been considering doing one in my D54.
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following this
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I had no D34 mainsprings in my stash. Surprisingly, my go-to replacement spring source, Titan XS didn't have a spring for it, either, even though they list most classic (and not so classic) springer models in their catalogue. Vortek springs are unavailable here (and too short-lived for me), while Maccari springs are available, but very expensive with the S&H + VAT (like any parts from the US) and take about a month to arrive.
So, I took a closer look at my Titan options. It seemed Titan #8, which is nominally for the HW95, old Webleys etc. was the best fit, having the same wire diameter, length and ID as the D34 OEM springs. A second potential candidate was the Titan #3, nominally for the HW77, D45 etc. It had the proper wire size, length and coil count, but larger ID.
My local source for the Titans was out of stock for most springs, like the #8 (thanks, Covid). They had a #3, so I took it. I had zero desire to spend weeks waiting for online overseas purchases to arrive for this gun.
Knowing that apart from length and wire size, the announced Titan sizes are more like suggestions than anything else (and no-one can wind a coilspring to the tolerances hinted at by the sales material), I tested the new spring on a Diana OEM rear guide I had rolling around in my parts box.
The Titan #3 fitted the Diana guide quite well, in fact much better than Diana's own springs do! The spring's narrower end took a semi-hard push to go into the guide, which I consider a minimum acceptable level. Sure enough, the Titan had an actual ID of 13.8mm, or a whopping 0.9mm under the nominal size. But, Titans are excellent and extremely long-lived mainsprings, which means a lot to me.
Donning the new mainspring on the new rear guide and putting them into the Diana, I was giddy to see how the rescue gun (I think it's fair to call it that) would turn up. Cocking the gun, I was very surprised to hear or feel zero indication that the piston had been latched by the trigger mech. Sure enough, the barrel returned the same way it came, with the stallion-like energy of a new Titan.
Was this a trigger failure or something else?
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I took a long hard look into the new-to-me T01 trigger, detailed in another thread. Pertinent to this Diana's saga is the fact that I took the trigger mech apart, cleaned it (it had a bunch of grime and some corrosion, like everything else in this gun), and learned, bit by bit, how the T01 functions.
The T01 is a fascinating piece of airgun engineering, almost otherwordly, with it's inter-sliding steel shells and three-ball sears.
A big plus for all this effort is that, going forward, I have zero qualms about going into a T01, pulling pins and taking out parts as needed. That’s like money in the bank.
At any rate, I couldn’t get the Titan #3 -equipped Diana Sport to latch, while the ancient, severely clipped mainspring cocked, locked and released perfectly.
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Turned out there was nothing wrong with the trigger system. What I hadn’t known is that the T01 piston and the space it allows for the compressed spring is not the same as in the D34's with later trigger models.
Cocking the Diana with the Titan #3 didn’t work, because the mainspring would get coil bound before the piston latch rod could engage with the three-ball sear.
Having never had experienced coil binding I had trouble identifying it at first (IOW, "nothing happening" can speak volumes). It was Robert (Madd Hatter) who prompted me to investigate this angle, while Hector provided the means to do it.
I calculated the coil bound length of the Titan #3 (number of coils x wire thickness), and tested and measured the space the mainspring in my T01 D34 needed to crunch into for the latch rod to engage.
The numbers didn't match: there was a 112mm maximum spring space while the Titan #3 would turn into a (temporarily) solid bar of steel at 115.5mm. Now there's your problem!
The situation between the trigger block front and the rear guide base in the latched-out-of-gun picture below is NOT the situation needed for engagement: the guide base needs to almost touch the trigger block for that to happen: after that, trigger spring force pulls the gap wider, as in the picture.
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The 34-yo. 34 had already stretched my springer know-how in various directions. Now it seemed the only way forward was to start cutting coils, a first for me.
I read up on the subject and applied the info to my general knowledge and experience on cutting, heating and grinding metal.
I wanted to test the techniques as well as the results so that I wouldn’t get the spring and myself into a non-reversible situation. At the same time I wanted to keep the project momentum going. So I decided to take out half coils at first, going through the steps of cutting, collapsing and leveling.
To keep the mainspring from losing temper, I put the Titan into a vise, gripping the spring quite tightly in the jaws, nevermind the black finish. The 30 lb. mass of the vise plus the tight grip would keep the heat from amassing in the mainspring body.
A cordless Dremel tool with a cutoff wheel went through the mainspring wire in a hurry.
Keeping the Titan in the vise, with only the topmost couple of coils exposed, I then heated the end coil using a butane micro torch. The narrow flame was key here, as it would only engulf the coil to be collapsed, without collateral damage. I also angled the flame carefully so that it didn’t lick what it shouldn’t.
Heating the coil red hot would make for great pics, but it’s such a dynamic, split-second type job that working solo, I have no pictures of it to show.
I used a pair of pliers to squeeze the hot end coil against the nearmost coil, taking care to attempt perpendicularity. I didn’t get the gap between the coils tightly closed on my first try, but at the least very much reduced.
Turning off the gas flame, only the outermost couple coils were hot to the touch, and only the end coil was really hot, so my plan to limit collateral damage had worked well. I then left the spring end to air cool.
I used a grinding wheel to level the new spring end. It turned out OK.
Having gone through the sequence succesfully I then took out another half coil and finished the end as before, reaching a calculated length for this particular mainspring that would allow for the piston to latch.
With the clipped Titan in hand, I quickly put the Diana back together to test the spring out. I was pretty much holding my breath when I pulled the barrel back…and heard the sweet click of the T01 sears grabbing the piston and not letting go. Success!
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Congratulations!! It's a learning experience for sure.
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After proof of concept, I decided to cut yet another coil off the Titan, to reduce the compression on the spring in the constricted piston space of the D34.
As it stands, the spring is now two full coils (plus set) shorter than when new, or 276mm against the untouched 304mm, or 1 1/8" difference. Calculating compression percentages, this is still quite a bit of length, but I wanted to get some data on performance at this juncture.
I finished up the newly cut end coil with my ceramic stones, degreased the receiver, piston and piston seal, and relubed the piston with a tiny amount of Ultimox on the front and rear bearing surfaces. Zero lube onto chamber walls, or mainspring, outside of coil faces on both ends. Less is more etc.
I put the Diana back together, with solid routine by now.
I then proceeded to break in the mods. I shot 50 Borner 10 gr. pellets to "seat in" the gun mechanically, then switched to 7.8 gr. Gamos for 200 pellets. I could tell the 34 behaved much better with the medium-weight pellets than with the heavies.
The 34 is quite heavy for it's slender look, a little barrel-heavy as well. Maybe unneccessarily long-barreled, in an old school kind of way. Losing a couple of inches off the barrel might improve ergonomics and handling.
The 34 was a breeze to cock. The gun's butt plate-less butt was a little too slippery while bracing the gun against my hip for cocking.
The 34 had a surprisingly loud, bangy muzzle report, which was not down to dieseling, with the non-dieseling Ultimox. it seems .177 cals really are louder than similar-power .22 or .25 cals.
The 34's T01 trigger performed flawlessly throughout. In its present settings, it has a medium-resistance single stage pull which I will be dialing out in the near future.
The 34's stock screws became loose at a record pace: every 20 shots in I would check them, and find screws that were ready to fall off! Every springer I've ever had loosens stock screws when new (or in this case decades out of use), but I've never had it quite this bad. I sure was glad I had brought a PH2 screwdriver with me.
In the big picture, the 34 turned ever smoother within those 250 shots. It's always a pleasure to start getting there. 500 pellets would've been even better, but I didn't have it in me, this session.
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Today I couldn't wait to chrono the 1988 Diana, at least a little.
R10 Match 8.2 gr.: 232 m/s / 761 fps, for just 14.4 J / 10.6 fpe. A letdown, for sure. I was expecting around 260 m/s / 18 J.
FTT 4.52 8.64 gr.: 220 m/s / 722 fps, for just 13.7 J / 10.1 fpe! Not looking good. It seems this 34 doesn't like the bigger head FTT's which are one of the most-quoted best pellets for D34 .177 cals.
Sniper Medium 8.49 gr.: 230 m/s / 755 fps, for just 15.0 J / 11.0 fpe. Picking up some steam. Maybe the gun favors lower-friction pellets, such as the Snipers, and Polymags?
Polymag 8.02 gr.: 238 m/s / 781 fps, for just 14.8 J / 10.9 fpe. Second-best, as the Snipers hinted at.
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At around 10 - 11 fpe, the Diana isn't shooting like a healthy D34 should. A Brit would be perfectly happy with this power level, but I'm not.
I think I may have overstressed the brand-new Titan with the bunch of coil bound compressions I inadvertently subjected the spring to, trying to make the piston latch, before realizing what was happening. Before the coil clipping started, I could see the Titan had become slightly wavy lengthwise, indicating some canting and fatigue.
Another suspect is the CAS seal, which did lower my 350 Mag's output by hundreds of fps, while also worsening the shot cycle. Maybe those seals really are a poor fit for any FAC level mainsprings.
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Great thread, thanks for sharing. And yes, the D34 loosens screws in a hurry! Link below to a thread that might help. I have flat washers and star washers sitting in a bag on my work bench.
https://www.gatewaytoairguns.org/GTA/index.php?topic=122338.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=122338.0)
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Check out the transfer port to see if it's the same size as a normal shooting 34. Have you shot a normal 34 where you live? What elevation do you live at? Elevation affects power in a springer.
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Great thread, thanks for sharing. And yes, the D34 loosens screws in a hurry! Link below to a thread that might help. I have flat washers and star washers sitting in a bag on my work bench.
https://www.gatewaytoairguns.org/GTA/index.php?topic=122338.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=122338.0)
I've used Hector's recommendation of Nordloc washers to great success. Just remember they must torque down against metal surface per manufacturer specs, so you need a small flat washer between the stock and nordloc.
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Thanks Robert & Chris!
We'll see if this gun settles as far as the stock screws go, like every springer I've tamed has. If not, there's always Loctite.
About the washers under the front stock screws: yeah, I will put flat washers under the star washers, which are eating the wood in this stock. I did the same with my 350 Mag several years back. And it's patently obvious that the 34 and the 350 are related, with the other only even longer (in power plant, not barrel).
Robert,
I did check the TP, like I do with every gun I tear apart. It's the age-old standard 4.0 mm TP of Dianas of many sizes and shapes.
I have never even held a D34 before acquiring this gun. I generally don't get to see let alone test guns unless I buy them. But I have a pretty solid picture of what a normal, healthy D34 does as far as velocity and kinetic energy go.
I live just a hair above sea level. Altitude is a non-issue.
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Duke,
My T05 trigger D34 averaged 787 FPS and just a hair under 12FPE with 4.52 H&N FTT 8.64 gr. Mine came with original box and papers and looked like it was shot little to not at all so numbers could change a little after a few hundred shots. And I'm at 36' AMSL (or 10.98 M for those not in the US).
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Chris,
Good to hear.
Off the factory, D34's have nicked, leaky piston seals (while some have oversized, super-draggy ones), oversprung mainsprings, insufficient / inappropriate lubing, plenty of burrs etc. etc. As a result, they typically don't shoot all that great without some work, and a basic tune job can easily up the ME's by up to several joules / couple fpe, while making the gun behave infinitely better.
The gun in question here has been deburred, fitted with an intact, low-friction aftermarket seal and a full-power high-quality aftermarket mainspring, and relubed in every important way. The expectations are different.
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In today's D34 news: rear sight happenings
I took the Franken-rear sight apart. Despite valiant effort by some hack 30+ years ago, the sight was useless: there was no effective elevation adjustment present, and the notch "leaf" could not be tightened down horizontally. Screws with no less than five different heads adorned the apparatus.
The original 1988 Diana open rear sight emerged underneath the Franken-parts. Sadly broken beyond repair (and no replacement parts available, AFAIK), the sight featured the remnants of a superior rear sight compared to the present offerings: the part-metal, part plastic 1988 sight had a very sturdy construction, with positive adjustment and zero play in the still-functioning windage adjustment. Things have really gone backward since the 80's in this regard.
To equip the Diana with a functioning rear sight, I replaced the old with a Xisico Diana present-day iron sight clone, which is in no way inferior to the Diana-made ones. A poor substitute for the original, it still affords sighting in.
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I like the replacement. I remember seeing your very first pictures and seeing all those screws in the rear sight and just thinking 'hey! happened there?'
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God Job, Ilimakko!
I would give the seal the "release force" test.
When you have the gun apart, put the piston inside and use a long tube that can make the stem go into the tube, it does not need to fit tightly, then using a simple kitchen scale, hold the gun with the piston (retracted), and the tube protruding, onto the scale.
Then press little by little.
The piston should start moving with about 1½ # of force.
Too little and you are loosing compression in the most important section of the compression phase. Too much and the seal is "robbing" energy from the shot cycle.
MOST D34's I have tried yield, with mild tunes right at the 12 ft-lbs region, in the HP tunes, they can yield up to 15 ft-lbs in 0.177" and up to 20 ft-lbs in 0.22" with GTO lead free pellets/ 16½ ft-lbs with lead pellets in the 14.3 grs. region.
Cocked/crooked springs will not perform well if the crooked section is at the back try reversing the spring and see if there is a noticeable impact in MV's.
BTW, you CAN straighten a spring, but then put the straightened section at the REAR where the guide will protect the straightness.
Keep up the good work!
HM
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Hector,
I reckon you missed an 'o' in your header ;D
I have been taking kitchen scale piston resistance measurements on every gun I tune for a couple of years now, ever since learning first-hand how tight seals rob a couple hundred fps, while loose seals lead to a bunch of other issues. I've been going with the "2 lbs. rule" for calibration (allowing up to 3# on magnum springers), which seems to work fine.
The CAS seal, freshly installed and lubed with a speck of Ultimox, moved in the chamber at a very high, 2.5kg / 5.5 lbs. resistance. Going by the seal diameter and previous experience, I knew this wasn't the whole truth.
For now I can't seem to find my back-of-the-envelope scribblings from a later point, but I remember the piston easing up drastically, the chamber resistance registering well under 2#, but a "close the TP and pull on the piston" test suggesting the seal was doing its job.
I fully suspect the seal isn't working well in this gun. My next step will be sizing an OEM seal and see how it affects the performance; I'd bet a couple of fpe appears from doing just that.
The canting in the Titan is quite evenly distributed along its length, with a bunch of minor deviations left and right from a straight line. How to straighten them out, I have no idea.
Going by the canting etc., I still think the Titan has been overstressed by the ~20 coil bound cockings altogether. One reason is that, starting from a very springy, muscular beginning, the spring is now really mellow to cock, close to effortless. So, even going with a perfect piston seal, I predict we'll be a couple of fpe under the target. But the proof is in the experiment.
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Great thread, thanks for sharing. And yes, the D34 loosens screws in a hurry! Link below to a thread that might help. I have flat washers and star washers sitting in a bag on my work bench.
https://www.gatewaytoairguns.org/GTA/index.php?topic=122338.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=122338.0)
I've used Hector's recommendation of Nordloc washers to great success. Just remember they must torque down against metal surface per manufacturer specs, so you need a small flat washer between the stock and nordloc.
I put flat washers under the star washers yesterday, and they were needed: there was stock wood powder coming off with the star washers, or business as usual. Not only for protection, the stock screws also seem to hold a bit better as well, although that may be an effect of the break-in taking effect.
Drew,
Thanks for the Nordloc suggestion! I'll look into them.
The gun sure did clean up esthetically, from getting rid of the Franken-sight.
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I'm still following, nice job on the "rescue rifle". Picture of it now please.
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There'll be pictures, Mike - good to know I have an appreciative audience!
I took the suspect CAS seal out. Now, after several hundred pellets and a chamber bath in Ultimox, the piston resistance with the seal was really low, around 100 grams or so. So, for the second Diana in a row, the Diana CAS seal is a dud. You can always whittle an oversized seal down, but there's no option for adding material. So, this'll be the first and last CAS seal in my possession.
The CAS seal measured 28.1mm in diameter, which has been a sufficient "overshoot" in some of my 28mm bore guns. I checked the D34 receiver ID: at the rear of the receiver, the inside diameter is 28.55mm!
I know receiver rear doesn't neccessarily have the same ID as the compression chamber, but there's no reason to think, nor indication, that they are that much different in this gun, either. The piston has the same resistance at the rear as in the chamber. Of course, going by the numbers, there should be zero resistance with a 28.1mm seal in a 28.5mm hole. Maybe the piston body itself adds some drag in the push test.
So, I fitted the piston with an Diana OEM 28mm seal, which had a whopping 28.9mm OD. To my surprise, the massively oversized seal, lightly lubed, moved inside the chamber with really quite proper fit, registering around 1000 grams, or 2,2#.
I'm going to break in and test out the gun with this seal as is and go from there. In my 350 Mag, an OEM seal of 28.6mm cut velocity by around 200 fps, even after a thorough breaking in, but it's looking like the 1988 gun has a very different bore, as far as piston seal sizing goes.
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I was curious about the CAS seal sizing so I measured 2 different ones that I had myself. One is from about 6-8 months ago and was removed because I damaged it, and the other is brand new unused, just arrived from an order I made the other week.
One was 28.5 and one was 28.49.
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I've been checking out those Nord-Lock washers. I would prefer to use a nifty mechanical solution to prevent stock screws from loosening, as opposed to a sticky chemical one (Loc-Tite).
The Nord-Lock washers I've seen for sale are double thickness, on top of being serrated. They look too thick to fit in the shallow counter sinks for the stock screw heads and any possible washers. This especially with Drew's point on needing to fit flat washers under the Nord-Lock ones. This because the Nord-Locks don't work on soft materials, and would likely eat up the stock wood if one tried.
The manufacturer says the Nord-Locks should NOT be combined with a flat washer:
"We do not recommend using a Nord-Lock wedge-locking washer in combination with a plain washer. Serrations on the Nord-Lock washer will grip the bolt head and your plain washer, successfully locking these two together, however this plain washer will not be locked against the contact surface which means it can rotate."
So, how do people use the Nord-Locks on springers? Do the stock screw heads protrude above the stock surface, with all the hardware under them? How do short front stock screws like the ones in my '88 D34 even reach the receiver yoke with triple washers installed? Do the stock screws stay put even with flat washers under the Nord-Locks?
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The new Diana 34 EMS actually comes with them from the factory, and they're fitted against flat washers.
So per Hector's recommendation of them, and seeing that on my 34 EMS, its exactly what I've done. I use a low viscosity cellulose nitrate to harden up the wood (most people use cyanoacrylate) and stick in a flat washer, and then the nordloc on top. I've not had any issue with the thickness of screws sticking out etc and the few times I've removed the stock, you'll hear an audible click of the serrations unlocking as pressure is released. So per what the manufacturer is saying, you're getting around the potential for the flat washer rotating because it is stuck down via adhesive to the wood stock.
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I picked up a few brand new Diana seals from Umarex just out of curiousity. Got near measurements as you just to further validate that Diana OEM seals are quite large.
Word to the wise, don't get ripped off like I did. They charged me 10 bucks shipping for 1.20 in actual shipping costs, and sold me the f-velocity ring instead of the compression seal for my D54. Is any experience with Umarex ever positive?
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Thanks Drew!
So, "gluing" the smooth washer down does the trick.
You know, I've been wondering about the large size of the Diana OEM seals, but this D34 with an oversized bore shows why they are the way they are. If you have a 28.5mm bore, you better have a piston seal around 29mm in diam. to start with.
The hitch is, unless you know what you have, per individual seal AND gun basis, you may well end up having a seal that cuts velocity by hundreds of fps. That happened with my 350 Mag, and I have heard identical stories from others.
In my 350's case, an OEM seal sized down to 28.4mm did the trick. The same seal in my 34 would've been undersized.
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Super informative thread!
Thanks for the meticulous notes throughout this process.
Archie
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Much appreciated, Archie!
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I picked up a few brand new Diana seals from Umarex just out of curiousity. Got near measurements as you just to further validate that Diana OEM seals are quite large.
Word to the wise, don't get ripped off like I did. They charged me 10 bucks shipping for 1.20 in actual shipping costs, and sold me the f-velocity ring instead of the compression seal for my D54. Is any experience with Umarex ever positive?
Positive experience....with Umarex? I dealt with them several times years ago and I'll never do business with them again.
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I picked up a few brand new Diana seals from Umarex just out of curiousity. Got near measurements as you just to further validate that Diana OEM seals are quite large.
Word to the wise, don't get ripped off like I did. They charged me 10 bucks shipping for 1.20 in actual shipping costs, and sold me the f-velocity ring instead of the compression seal for my D54. Is any experience with Umarex ever positive?
Sorry you got that, Drew.
I would talk to the supervisor and explain that you got the wrong seal and that they need to send you what you paid for, and that if they want the wrong part back, they need to send you a shipping label and an MRA.
It's annoying to pay for Shipping AND Handling a lot more of what actual shipping costs, but that is a US habit and the dislike of that habit was what created the monster that Amazon is . . .
Keep us posted.
HM
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After replacing the sorry CAS seal with a Diana OEM seal, I put around 100 pellets through the D34 to break in the new seal.
A chrono session today gave the following results, averaged out:
R10 Match 8.2 gr.:
274.8 m/s / 902 fps
20.1 J / 14.8 fpe
FTT 4.52 / 8.64 gr.:
259.7 m/s / 852 fps
18.9 J / 13.9 fpe
Sniper Medium 8.49 gr.:
262.6 m/s / 862 fps
19.0 J / 14.0 fpe
Daystate Heavy 10.25 gr.:
229.1 m/s / 752 fps
17.4 J / 12.8 fpe
Polymag 8.02 gr.:
271.8 m/s / 892 fps
19.2 J / 14.2 fpe
Exact 4.52 gr. / 8.44 gr.:
259.4 m/s / 851 fps
18.4 J / 13.5 fpe
....
So, replacing the piston seal (while doing nothing else) increased muzzle velocities from 26.7 to 42.8 m/s, or from 88 to 140 fps! Muzzle energies increased accordingly, by up to 5.8 J, or 4.3 fpe.
The biggest gainers were the R10's and the FTT's. The low-release-pressure JSB's were a bit mellower. The JSB Daystate Heavies had much lower KE's than any of the mid-weight pellets, telling how this setup works best at around 8.5 gr.'s.
The Sniper Mediums varied in velocities pretty wildly, expressing the quality issues these otherwise high-performance pellets have, or had.
Polymags had the best shot cycle and one of the highest KE's.
The 34 year-old 34 performs now at a 100 % healthy level, and that feels really good! Hector had it right (as usual) in that the piston seal was the issue. I sure wouldn't have guessed that an almost 1.0mm oversized seal would be just the right medicine for this gun.
I'll start the accuracy testing with FTT's and Exacts, with some Polymags thrown in.
One issue I need to deal with first is the rear sight, which refuses to stay put with the normal stresses of shooting.
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Glad you got it sorted. The more I shoot mine the more I it. I like it so much my wife is threatening to buy me a custom stock for it for Christmas. I might just let her ;). Thanks for the thread, some useful info for other 34 owners in here.
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nm
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Whats the plan with the rear sight? Try to find an OEM type replacement? Swap for something else like the ever popular williams diopters?
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Thanks, Chris!
Here are some pics as promised: she's come a long way from the 30-year sentence in a damp, dark cell.
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More:
The old lady has a pretty burry muzzle crown to my eyes. I reckon I'll recrown it, to just about complete my Diana 34 fixer certification.
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That’s just so cool. Not something you see every day. I love seeing old things resurrected. Almost as much fun as doing it yourself!
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Actually, the rim of the bore does not look too bad.
The other scratches should not effect accuracy.
-Y
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The scratches on the face of the muzzle have obviously nothing to do with pellet flight. Looking at the actual crown with a 20 X loupe I can see the very ends of the grooves and lands look jagged. That can and does affect pellet flight.
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That’s just so cool. Not something you see every day. I love seeing old things resurrected. Almost as much fun as doing it yourself!
Chris,
Thank you! That's the thing with discussion forums - you get to "take part" in interesting stuff outside your own tool shop / shooting range.
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Your 34 has had a hard life for sure. I'm trying to think what would make those "knife edge" marks, not once but several times?
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Mike,
Looking back how I mishandled even expensive stuff I owned at age 10, I think it's best to not think what this poor German lady went through in the '80's.
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Great job on the old RWS!!!
I have an old RWS from 1985 - which may have been the first year they are made, I'm not sure.
I'm about to start a post about it - probably need a new barrel.
It's cool to see that it's not the only older 34 still shooting
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Great job on the old RWS!!!
I have an old RWS from 1985 - which may have been the first year they are made, I'm not sure.
I'm about to start a post about it - probably need a new barrel.
It's cool to see that it's not the only older 34 still shooting
The 34 (as a a model designation with THAT number) was introduced in 1984, BUT the basic architecture was introduced MUCH earlier. In the 50's.
Things that changed and meant new model numbers have been: Compression chamber dimensions, piston and piston seal designs and materials, and trigger designs.
Your 34 could, theoretically be updated to a T06 trigger and piston, if you so desired.
Barrels were still being sold by UMAREX up to a few months ago, so it may be wortwhile checking what they have.
Good luck and keep us posted!
HM
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I tested a select bunch of pellets for accuracy in my 34 yo. 34, shooting 5-shot groups at my customary 30mm bull at 20 meters (22 yards), standing, offhand, using factory open sights.
A black horse turned out the most accurate so far: H&N Baracuda FT 9.57gr. I wouldn't even have these pellets if it weren't for the H&N pellet debacle some six months back that ended up with the company sending me compensatory pellets, among them a surprise tin.
These pellets have a very good cycle and also yield good chrono numbers, at around 248 m/s / 814 fps and 19.2J / 14.1 fpe.
The tin doesn't have the usual head size sticker, but "sample" hand-written on the bottom. I have no way of telling if these are 4.50's or 4.51's, which are the two sizes the Baracuda FT's come in.
FTT 4.52's were second best in accuracy, even if clearly not as good as the BFT. The FTT's are also pretty nasty to chamber in this gun, requiring confirmation pushes with the thumb.
Sniper Mediums were third best. I'm basically relieved they weren't the magic pellet for this gun, these being out of production.
Exact 4.52's were nothing to write home about, shooting much bigger groups than the previously mentioned pellets. They chamber like a rain drop gets eaten by the sea, ie. zero resistance, very different from the H&N's. The Exacts chronoed around 258 m/s / 846 fps, and 18.2J / 13.4 fpe.
I haven't tested Polymags yet. Given the hints dropped by the gun so far, I'm not expecting much there, but am very willing to be proven wrong.
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Interesting. Same experience in my T05 34 with the FTT vs JSB/AA pellets. The Baracuda 10.65 are accurate in my gun as well but the FTT give more FPE. I’ve never seen a 9.57 Baracuda so obviously haven’t tried those!
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The Baracuda FT's have much thinner skirts than the FTT's, or even the classic Baracudas. I reckon that's the reason they seal so well in a mid-power gun such as this, and with their smaller heads they are easier to load and have no excessive friction going down the barrel, either.
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Sighting the 34 in, the sad fact was:
The factory sights cannot be adjusted low enough for medium distances:
at 22 yards, with the rear sight bottomed out, the mid-weight pellets (c. 8.5gr.) printed app. 5 – 6” high, the mid-heavy pellets (c. 9.5gr.) app. 4 – 5” high, and only the heavy pellets (c. 10.5gr.) leveled with the target.
The front sight would need to be higher than it is, for the sights to be usable inside 25 yards. How much higher? I haven’t done the calculations.
I’m semi-seriously thinking I need to start making my own iron sights to get something usable. Too bad I don’t have access to a machine shop. But hey, small parts for guns were shaped with files for centuries, and surpassing the quality of the factory sights is far from a Herculean task.
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Recently I upgraded my rescued 34 Sport with a new D36 Commemorative stock. The original 1988 Sport stock was just too slippery, flaky-scratched, and 80’s blue.
The new stock was a reduced-price specimen, due to ambiguous damage. I didn’t get a picture of the damage that I asked from Schneider, so I took my chances, and am glad I did: there are some tiny, innocuous splinters on the inside edge of the inletting, affecting neither function nor looks. Pretty good for a 14 % discount.
The stock has a longer LOP, a much-needed rubber butt pad, plus a raised comb and checkering. It’s just an all-round a classier, better-fitting proposition than the Sport stock. Still, it has the shorter, old-style front stock that leaves the pivot joint exposed and accessible, which is a definite plus to me.
A surprising issue did turn up, though: When I installed the new stock to the 1988 metalwork, the gun would not cock. There’s just a solid, dull stop at the end of the cocking stroke, before latching would occur. The breech block, the barrel and the cocking arm travel freely, the stop is internal in nature. Echoes of the coilbound issue I reported here last fall, but that cannot be the issue now: the gun cocks and locks perfectly in the original stock.
As far as I can tell, the D36 receiver inletting, detailing and dimensions are identical to the original stock (see the pic). The only visible difference is the depth of the trigger guard inletting, which is much shallower on the Sport. Consequently, the 1988 trigger guard doesn’t fit the D36 stock. But with or without the guard, the gun doesn’t cock.
What might be the issue here?
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Forgot to add a picture of the gun in its new stock:
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To test things out, I fitted the D34 with the D36 stock with the plastic trigger guard off my 350 Mag. Not only is the plastic guard much thicker at the base than the steel one, it also has a slightly different type of front screw, which also grabs the action at the rear.
Lo and behold, the gun cocked and locked normally! Problem solved, although I lament the forced switch to a plastic trigger guard, which I don't have a spare of, or the front screw, anyway. In retrospect, I should've ordered these with the new stock from Schneider. They charge really hefty S&H for the tiniest of orders, and I just checked off my wish list with a big order off them, so things have to wait.
At least I can test shoot the new-stocked 34, since the 350 Mag is in bits for now, anyway, with its detached front screw yoke waiting for supplies and time to fix.
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As noted earlier in this thread, the original 1988 front sight of the 34 Sport is too low to zero in at 25 yards, even when the rear sight is bottomed out. To correct this, I needed to further modernize the 34, using the tunnelkorn front sight of my 350 Mag, which is a couple mm's taller.
The 350 Mag Tunnelkorn had been taken apart with the downfall of its parent gun. To my surprise, I had real trouble getting the fine thread of the knurled bead-tightening ring started on the tunnel - the ring desperately wanted to tilt a bit and seize up, risking stripping. A bit of WD40 (which I rarely use on airguns) on the threads made things turn perfectly.
The original front sight was tightly screwed to the barrel dovetail, with it's extra hardware store nut. A screwdriver couldn't hope to move the screw, so I loosened the nut with tongue-and-screw pliers. After that, the switch was smooth sailing.
I hope to see this Sunday how the rescue gun with the new stock, trigger guard and sights works.
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Schneider Stock. Do you happen to have the website for Schneider stocks? Did a search and could not find them. I have a newer Diana 34 classic (NOT EMS!) and would like a better stock. Thanks and great info so far!
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Awesome job on this.
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Try this:
https://www.versandhaus-schneider.de/product_info.php/cPath/40_94_140_700/products_id/4274 (https://www.versandhaus-schneider.de/product_info.php/cPath/40_94_140_700/products_id/4274)
Schneider sells replacement stocks for Weihrauchs, Dianas, and assorted other airguns. They aren't Schneider stocks, but OEM ones.
And thanks guys!
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I really appreciate this very much. My "Classic Diana 34" is a little rough around the edges. But she has great bones. ;)
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Today I took the renewed D34/36 for a wintery spin.
The new D36 stock feels so much better than the original, as well as looks so classy I have a hard time putting the gun down.
Despite the fact that I tightened the front sight as far as the screw would let me without failing, the front sight started creeping back on the dovetail as soon as I put a measly five Baracuda FT's through the gun (you can see it in the pic if you look close). The vertical stringing apparent in the following two groups got its explanation.
So, accuracy testing went out of the window. No big surprise there, but it goes to show that without Loctite there's zero hope of keeping the OEM sights on even a mellowish D34.
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As today's springer mini chore, I Loctited the front sight assembly on the nose of the 34. I cleaned the pertinent bits with acetone, assembled the sight on the dovetail, applied Loctite Blue to the tip of the tightening screw, as well as the corresponding tap on the sight, and tightened things down.
I didn't bother degreasing the dovetail joint to make everything clean and dry; the procedure above has been sufficient so far, and I'd rather have some Ballistol in the dovetail too, to curtail rust, which has already ravaged this gun for a lifetime's worth.