Diana 27 – Part 8

by B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7

Today, we’ll revisit our old friend for the part many of you have been waiting for–look inside! This will be a disassembly day, with a description of what to do and how it goes. Before I start, I’m going to gather several plastic Ziplock bags of different sizes to keep all the parts in.

Step 1: remove the stock
Three screws hold the action in the stock. Two at the end of the forearm and the front triggerguard screw are all that have to be removed and the metal comes out. Once out, I began to see the history of this gun. It appears to be virgin–never having been out of the stock before. The insides will tell more.


The action is out of the stock. You can only see one cross pin here because the end cap covers the other one.

There are two crosspins that hold the trigger parts in the spring tube. The trigger parts hold in the mainspring under tension. The back pin is hidden under the sheet metal end cap; once it’s off, you see the pin. But that pin isn’t holding anything, because it falls out on its own. Only the front pin is under tension.


There’s the rear pin!


Which promptly falls out.

Step 2: into the mainspring compressor
The barreled action now goes into the mainspring compressor. Since the 27 is a short rifle, the compressor had to be adjusted for it. When setting up to work on a Diana 27, know that the factory mainspring doesn’t have a lot of precompression. So it will only back out a couple inches when the compressor takes off the tension.


Tension is put on the trigger tube to relieve the single crosspin that holds the trigger parts in the spring tube. I use a lead ingot as a pusher block because it won’t mar metal surfaces.

Step 3: relax the tension and remove the trigger parts and the mainspring
With a Diana 27, you want to relax the spring tension slowly because nothing is held together inside. It all stays together because it’s inside the spring tube, and you’re now taking it out. Be especially careful of the strong trigger spring that is between the dark inner trigger tube and the large silver outer tube.


The mainspring is relaxing. The dark tube you see emerging from the silver tube is the inside of the trigger unit that contains the three ball bearings. Be very careful not to lose them! Also, see how the dark tube climbed up from the silver tube? A strong trigger spring is pushing them apart.


The mainspring is completely relaxed. This is a stroke of about 3.5 inches, so that’s how far the compressor had to move.


There’s the powerful trigger spring. That dark slot is where it fits.


The dark metal tube with the three ball bearings slides out of the silver tube. See that huge “dent” in the silver tube? It’s one of three ramps spaced every 120 degrees around the tube. They control the ball bearings when the dark tube is inside.

Keep all the parts in plastic bags so they don’t get lost.


There are the three ball bearings. When we assemble the gun again, I’ll use tacky grease to hold them inside the dark tube until they’re captured by the gun.


The mainspring has a few kinks, but it’s good enough to re-use.

Step 4: time to remove the barrel
The barrel has to come off to free the cocking link from the piston. When I removed it, there were obvious indications that this rifle had never been apart. Lots of rust in hard-to-clean places and lots of gritty dirt was coming off.


To disconnect the cocking link from the piston means the barrel has to come off the mainspring tube fork. The small lock screw is first, followed by the barrel pivot screw.


When the barrel is removed from the fork, you can see the thrust washers on either side. On the Diana 27, they’re asymmetrical. There are two on the left side and a special formed one on the right. The state of their surface appears to be vintage factory. In other words, the gun has never been apart.


Once the barrel is separated, the cocking link slides to the enlarged hole at the front of the cocking slot and can be removed.


It removes this easily.

Step 5: remove the piston
The piston slides out easily. If you don’t remove the trigger, you have to pull it like you’re firing the gun to clear the piston as it comes out.


The piston is now out. Note that the end of the piston is a mushroom-shaped knob. That’s what pushes the three ball-bearings out of the way (up the ramps) as the rifle is cocked. At the end of the stroke they are pushed into the groove in front of the knob. The pressure of those three balls that have no place to go, holds the piston in place.


You can clearly see the groove where the three balls sit, holding the piston.


The piston seal is definitely leather and looks new! I think it’s original to the gun.

And that’s the sequence of disassembly of the Diana 27. Believe me, it goes together easily too, if you can remember what you did when taking it apart. These photos should guide you.

Cleaning is the next step, and this is a filthy air rifle. There are some dark spots that almost look like moly applied 15 years ago, but nothing else is consistent with that. I’ll continue to observe and see what I find as I clean the gun. I won’t blog that job, but I’ll talk about it in the assembly report next time.

54 thoughts on “Diana 27 – Part 8

  1. BB,

    Thank you for this report. I would like to take apart my old Slavia 630. Mainly, I want to learn first hand about the inner workings of air rifles, secondly, I would like to replace the spring and seals, etc. I know I can do it with the right tools. Is there any specific infomation on the Slavia and how to take it apart?

    Thank you


  2. Proper ammunition for Gamo Whisper,

    I would like to hear suggestions for this rifle. I got a box of Crossman premieres Lights and have been using it with the Whisper.

    All my groups have shrunk significantly with this ammo. The difference with respect to the ammo I used previously is truly amazing. Does anybody suggest other pellets for the Whisper?

    Thank you
    T.E.



  3. TE, I’ve done a number of OLD Slavia’s (1950′s and 1960′s), but no newer ones . I’m not familiar with the model 630, although I’m quite sure that it wouldn’t be that difficult. I’ll do some research and get back to you.

    BB, with all the old guns I’m doing for Wayne I’m finding that leather seals in general seem to hold up very well. Out of maybe a dozen or so models I only found two – the Markham “D” I blogged a little while ago and his Romanian-built “Pionier” – in which the leather seals were kaput.


  4. MrB, Kevin, Matt61,

    Yeah, I won the Crosman Summer House contest late last summer. The prize at the time was either a Disco or a “new-crazy-girls-gone-wild- incredible-secret-ultra-cool-no-idea-when-it’ll-be-done-unnamed-new-gun”. So, you know, naturally, I was intrigued. Hopefully, they’ll ship one in just a few more weeks. The ballistic promises of the new rifle–as well as the dual fuel capability–has sort of put the kibosh on the purchase of a few other new guns.

    Derrick


  5. BB,
    It occurred to me while reading this blog that working on grimy and greasy rifle and photography are two things that are hard to do at the same time. Was you wife able to do the photography for you or did you have to repeatedly wash up, take pictures, and get dirty again?

    I want you to know that I truly appreciate your blog and feel indebted to you for producing it faithfully, day after day.


  6. derrick38,

    Congrates–yes and I know thatyou’ll let us know your impressions, etc.

    wogup,

    Maybe it was the other way around.

    Have a great day oneand all!

    Mr B.



  7. T.E. – I found JSB Exact 8.4 pellets to be way more accurate than other pellets I tried. I never was able to try CPL’s, though, so I can’t comment on those.
    -George



  8. BB,
    I love this kind of blog post. The ball bearings are a really interesting mechanism. The seal does look brand new underneath the grime.


  9. Yes, the plastic bags for parts are important. I was just mounting rails onto my Walther Nighthawk and lost track of a tiny nut that dropped into my thick, dark brown carpet. Argh. It took forever to find it.

    Matt61


  10. Vince,

    thank you! My Slavia is back in my home country and I am planning on retrieving it, partially dissamsembling it and bringing it back to work on it.I hope to do this within the next two months

    I pressume there are no issues with customs in the US




  11. BB,
    If I need a breech seal for an old
    BSA Comet, or any other break barrel for that matter, what might be a good source?
    Thank you for the daily entertainment and education.
    George



  12. B.B.,

    Wonderful photo’s in this part 8 of the Diana 27 series.

    I really appreciate these articles that empower and, in some cases, create confidence in us to venture inside our airguns.

    kevin



  13. TE, I did find an illustration of the 630 and it appears to have the same general construction as the 634 (as I suspected). I’ve got a 634, but it’s the one gun I have that I’ve never taken apart.

    So I guess I’ll have to take it apart.

    jgairguns.biz does have seals (about $15 ea, as I remember). Don’t know of any other source for ‘em.




  14. Matt61,since BB already told you about keeping A strong magnet for shag rug parts retrieval,I will share with you something to aid in enjoying your Walther Nighthawk.If you have 1 paper towel and a roll of electrical tape,you can convert the Nighthawk’s “compensator” into an effective silencer!take the paper towel,fold in half,wrap around compensator covering all holes…then wrap tape in the direction the paper overlaps{this will pull the paper tight.continue wrapping the tape,overlapping a spiral until you have 2 complete layered wraps of tightly laid tape.now re-install compensator on gun:the “loudener”has become a silencer!!!ENJOY!FrankB


  15. Kevin said…
    “The FX whisper is known and named for being quiet and in .22 cal it’s rated as a 28 ft lb gun. Is it a 28 ft lb gun?

    I noticed you sold the whisper on the yellow awhile back. If you don’t mind my enquiring mind, why did you keep the cyclone over the whisper?”

    Kevin,

    Sharp eye, yes I sold the FX Whisper a while back.
    As I am sure you know the benefit to trying a used rifle when you are not 100 % sure is it is practically free. The Webley Raider and FX Whispers both sold for what I Pd. I did make a small concession on the Raider by including a $20.00 fill probe and on the FX Whisper I threw in a scope. Since I have been reducing my gun inventory I had 6 unused scopes on my bench, and as you might guess the one I gave was not a favorite.

    I was also able to revisit an R-1 as I bought a new in box blem in a fit of nostalgia – that lasted a week and cost $10.00.

    Anyway, back to your questions. Power wise I am confident the Whisper would be a 28 ft lb gun in .22 cal. – mine was a .177 and easily achieved the advertised 18 ft lbs.

    I kept the Cyclone over the Whisper for multiple reasons. First, I know there are many supporters, but I just cannot connect to a plastic stock. The thumbhole was nice and it was very easy to shoot off hand, but I could not rub and worship it like a piece of lumber. I’m just not a blow up doll kind of guy.

    Next it lacked a fill gauge, no biggie but the Cyclone’s spoiled me. Loading the magazine on the Whisper was also a tad annoying, but it held 16 shots instead of eight – so just a slight nod to the Cyclone. The Whisper is a fixed power affair; the Cyclone has 3 distinct setting.

    Lastly, the Whisper could shoot only the two heaviest .177 pellets well, but the Cyclone can shoot a bunch. I have been able to find pellets that are outstanding on each power setting. I can plink at 14 ft lbs, take crows and squirrels at 24 ft lbs and still have 33 ft lbs if I ever need it. (33 ft lbs is too much on a squirrel at 45 yards –went in and out plus through my cedar fence)

    Not only did the Cyclone nudge out my Whisper, I also sold my PW tuned HW97K, as the Cyclone is now my “go to gun”

    Volvo


  16. TE, I meant to say that the PISTON seal was about $15. The breech seal looks like an ordinary O ring, dunno what size.

    When I get a chance I’ll see how my 634 comes apart, but right now I’m busier than a one-armed paper hanger. Can’t promise anything soon, but it doesn’t sound like you’re in a terrible hurry…



  17. Volvo,

    Thanks for the insight.

    “I’m just not a blow up doll kind of guy.” I just had to pick myself up off the floor! I understand wood vs. synthetic. I think I remember your hw30 with black and chrome (silver)? Stunning.

    I saw the pw tuned hw97k. Two months ago I would have bought it in a heartbeat. I’m somewhat surprised at myself for the springers I’ve sold but the pcp’s have spoiled me. I’m not sure I’ll ever sell the R7, fwb 124 or diana 27 but the others are on borrowed time.

    I’m amazed at the speed of my bizarre evolution in airguns. I’ve had a wonderful opportunity (as you have) to sample a good many airguns for very little cost (sometimes only shipping cost).

    I’m now at the point where the priorites are ease of accuracy+firepower (read multishot) with adjustable ft lbs and stealth (cotton balls colliding quiet).

    I want to thank you for your time since it seems my priorites have always been on your heels in this hobby.

    kevin


  18. Be careful when undoing the stock screws!my old model 27 from the fifties had real tight holes in the stock and one of the screws chipped the wood coming out.
    Not that it will happen to yours but heads up!.
    Not sure how to get around that issue???Maybe the wood was real dry(colorado).


  19. B.B.

    That’s a good idea. I was thinking of using a Surefire flashlight to produce a reflection when my fingers found the nut.

    FrankB, thanks for the tip, but B.B. has got you scooped. There was a blog about this many moons ago. I’ve just wrapped tape around the muzzle brake without a paper towel, and it works well. It sounds like something out of James Bond. I’ve also been enjoying the accuracy of the red dot sight; it really does make a difference. But I don’t plan on taking this rig to the shooting range.

    Kevin, it looks like you’ve opened the door to more PCPs. Is the Marauder next? I suppose once you get past the heartbreak of the pump, the price is really not so bad.

    Matt61


  20. Matt61,must have been in an archive I missed.I never claimed I’m L.Davinci!by the way,the paper towel is so it all removes easy without the gummy mess from electrical tape everywhere…FrankB


  21. Matt61,

    I got past the “heartbreak of a pump.” I bought a tank. Pure shooting, no distractions.

    Marauder might be next. I like what I hear so far with few exceptions.

    Anonymous that chipped the wood when taking screws out of his diana 27,

    Where are you in Colorado?

    kevin


  22. Kevin,

    I still have the black and nickel HW30S. The black stock is actually painted wood, which I like the feel of. Combined with the nickel action and barrel, it is a nice look and about as wild as I get. Also has a PW advance tune.

    I almost pulled the trigger on a Walnut and nickel HW35 in .177, but I’m still on the fence. My choices, all in .177, are an older Match rifle, a PCP (maybe Marauder), or the above HW35.

    Volvo


  23. Volvo,

    Let’s not forget the gold bling on the webley?

    An older match rifle? Have you been watching the fwb 300s on brads? A classic that you can still find parts for. I’ve been tempted but am waiting for B.B. to finish the Marauder testing before deciding on my next.

    kevin



  24. BB,

    I’m looking forward to the rest of this series. I just picked up a nearly unused Model 35 from 1976. It shoots great, but could probably use a clean and lube at some point.

    This is my first springer, so I’m a little hesitant to take it apart while everything seems to be working well. Any tips on what to lube without disassembly? I’m mostly concerned about the leather seal.


  25. Kevin,

    The 35 is powerful enough to detonate, so use silicone oil to lube the piston seal. I would start with 5 drops and go from there. Expect the gun to smoke on most shots.

    The 35 disassembles just like the 27, so follow along with my report and see what you think.

    Your rifle can also use oil on the pivot point, which goes in on both sides of the base block. Regular petroleum oil is good for this until you disassemble the rifle. Then switch to moly grease.

    Clean the barrel with JB bore paste for the best chance of accuracy.

    Other than that, just shoot the gun. The mainspring is probably dry, but I wouldn’t oil it unless it crunches as the rifle is cocked. Use petroleum oil there, too, but be sparing because it will migrate forward into the compression chamber.

    B.B.


  26. Hi all,
    Thanks for Mr. B. directing me here from an old blog, still not sure if I’m in the right place.
    I oiled the pump head to my Sheridan C series bought in the 70′s and put a couple of drops on the probe’s O-ring today, no go. I can’t find the manual or parts, is this gun worth what it would cost to send it off for repair if needed?…..Les


  27. hey guys iam really new to the air rifle community.i fired a friends rifle a few times and i am hooked.i did some searching and came up with a rifle the airsoft utg type96 which has all the features i like except that it shoots bbs and i would like one that shoots pellets because i think they are more accurate and better for hunting .to be specfic what i am looking for is a spring action rifle which fires muliple pellet shots . am i correct with my pellets vs bbs assumtion thanks for any suggestions that you may have.


  28. Les,

    You came close to the most recent blog. This one was done on April 9, 2009 but the most recent was done on Friday, April 17, 2009. A new article is written every day, Monday-Friday by B.B. You’ll find most airgunners asking and answering each others questions under the most recent article. If you copy and paste this link it will take you to the most recent article everytime (you may also want to bookmark it for future reference):

    http://www.pyramydair.com/blog/

    I noticed that you originally posted your question under the article B.B. did on the repair kit available for the newer benjamin/sheridan pumpers. Did you use pellgunoil on the pumphead? How many drops did you put on the pumphead? How long did you let it sit and soak in before pumping and attempting to shoot the gun?

    The value of your non-working Sheridan C series depends on the outside condition and which C model it is. Model C? Model CB? Model C9? Model CB9?

    Benjamin still manufacturers the 392 and 397 which are very similar to the sheridan c models. The 392 and 397 are around $160.00 new.

    If additional oiling of the pumphead doesn’t bring your fine rifle back to life you may want to contact this man and find out what he would charge to repair your gun:

    Rick Willnecker Contact him at airgunshop@aol.com or call 717-382-1481

    kevin


  29. reddot,

    Welcome to airgunning!

    The UTG Type 96 is an airsoft gun. It shoots 6mm plastic BBs at less than 500 fps. No airsoft gun should be used for hunting. Airsoft guns can be used for gaming purposes (skirmishing) and shooting at inanimate objects, but they have insufficient velocity & energy to humanely take game.

    Steel BBs have been used in airguns (not airsoft guns) for a really long time. Guns specifically made to shoot steel BBs are also not suitable for hunting. Not only are they too slow and have insufficient energy, they're not accurate enough (for the most part).

    If you want to hunt with an airgun, a pellet rifle should be your choice. There are also some powerful pellet pistols that'll do the trick.

    Tell us the game you want to hunt and the distances you want to hunt so we can make some gun recommendations. It would also help if you told us how much you want to spend. There's a huge price range for airgun!

    Edith (Mrs. B.B.)


  30. Thank you Kevin,

    I did oil the pumphead this morning, which has worked in the past. Looking up the serial# 439117it appears to be manufactured in 1985, thought it was older.
    How long do you recommend letting it soak before pumping? Thanks again, Les


  31. Les,

    I brought an old sheridan blue streak back to life a couple months ago. Wasn’t my gun but a friends and before he sent it off for repair we put 5 drops of my pellgunoil on the pumphead and let it sit overnight. Didn’t work.

    We then put ten drops of pellgunoil on the pumphead and worked it in every 5 drops. Let the gun sit for 24 hours and it was shooting again. It’s shooting around 520 fps which is a little weak but he’s happy.

    kevin



  32. thanks for the quick response. i would primarily be using it for pest elimnation such as rats and birds the breakbarrel takes to long between shots which is why i would like it to be a multiple shot rifle.because of my location, acess to refills for gass powered ones will be a problem.i would like to use it for target practise at about 70ft or more my budjet is $150 or thereabout it can be a used rifle


  33. reddot,

    Your criteria for an airgun is a challenge.

    You want a repeater for hunting and because of hunting the gun needs to be somewhat powerful and should be a pellet gun since, as Mrs. B.B. said, bb guns are not suitable for hunting.

    Let’s talk about a repeater. By definition this is a gun that has the capability to have more than one round of ammo on board that can be readied to shoot without loading again. This means a magazine in pellet guns usually. A magazine limits the types of pellets you can use and a magazine can deform a pellet either when you load the magazine or when the bolt loads the pellet into the breech. Deformed pellets result in inaccuracy. Be aware of these drawbacks.

    Whether or not the airgun you choose is a repeater or not you must have a way to fire the pellet. Let’s talk about your choices. You have apparently eliminated pcp’s (Pre Charged Pnuematics) since you said “access to refills is a problem.” Your next choice would be a multi-pump but I assume from your comments that this would defeat your goal of a quick follow up shot. The next choice would be a spring gun. For each shot in a spring gun you must cock the spring. The AIR SOFT gun you initially mentioned (airsoft utg type96) cocks the spring when you draw the bolt back. This kind of “minor work” to cock the low powered spring in the UTG Model 96 works because it only has to shoot a plastic bb. You need more power for hunting, more power to push a lead pellet and that means a more powerful spring. This powerful spring will need to be cocked with a sidelever or by breaking the barrel. Your last choice would be a CO2 gun that will require cartridges.

    The last piece of criteria I’m having trouble with is the price range of $150.00. I don’t have a suggestion of a gun that does everything you want for this price.

    Look at the Daisy Powerline 953 target pro that is a single pump, repeater, in .177 caliber pellet. It only shoots 500-550 fps so it would only be suitable for hunting at VERY close distances (that distance that you are absolutely sure you can hit a nickel).

    The RWS 850 air magnum is a CO2 repeater in .177 will shoot 700-750 fps. This velocity will allow you a little greater hunting distance but again, don’t pull the trigger on a pest unless you’re absolutely sure you can hit a nickel at that distance.

    Now for the advice you didn’t ask for. I strongly encourage you to consider hunting with at least a .22 caliber airgun. I would also strongly encourage you to consider a single shot pellet gun. Your choices of a gun is much greater, your target shooting accuracy will improve at a greater pace when you take time to shoot one pellet at a time and your hunting won’t suffer much, if at all, since pests usually only allow you one shot anyway. Whether or not you have a repeater, after your first shot you’ve either hit the pest or it has fled out of sight and/or range.

    For your budget and criteria I vote for the RWS Model 34.

    kevin


  34. reddot,

    Kevin gave you a great answer. You have to understand that airguns are not like firearms, and repeating airguns are either beyond your budget of too weak to work.

    If I were you I would look hard at a used RWS Diana 34 in .22 caliber.

    B.B.


  35. thank you Kevin and BB for the very insightful information.i now know why i could not find what i was looking for cus it probably dose not exist.thanks for the sugestions




  36. Are you able to safely disassemble a spring air rifle? Do you have a mainspring compressor? That's what this 8-part report was all about.

    If you feel this is too difficult or dangerous (the mainspring is extremely dangerous) then the rifle can be repaired by Umarex USA, which is also RWS USA.

    http://www.umarexusa.com

    B.B.




  37. Hi ,everybody,I need some help .I disassembled and reassembled my Diana mod.27 to clean it and change some parts.When i compress the main spring with the barrel ,the trigger does not work.What is the problem?
    Mike


    • Mike,

      The trigger unit is probably assembled incorrectly. Are the three coiled springs held on the inner black metal sliding part? Are the three ball bearings on the inside and able to slide around when the inner part slides inside the outside silver cage?

      Are the parts arranged in the same way as they are shown above?

      B.B.


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