HW97 Tune up

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  • HW97 Tune up

    This is a copy from the old forum of the thread I made previously on tuning a Weihrauch HW97. There may be a few links and pics missing which I'll try to fix.

    HW97 Tune up -

    Posted 29 Jul 2013 - 08:59 PM
    I was debating whether to start a new thread or not as there's already a few tuning threads.
    Most of them pertain to the installation of various kits.
    So this one will get a bit of Matt's treatment and we'll see how it goes.

    I've had the gun for several weeks now and have been running it in.
    The twang is annoying me to the point that it went under the knife so to speak this evening.
    Once you shoot a tuned gun you'll never be happy with something sub par.

    I'll try to give you my observations along the way.

    First thing I did when I got the gun was take the stock off and loctite the screws in place.
    10 metre groups were basically one hole.

    Moving out to 25 metres showed a lack of consistancy.
    So I've been trying different pellets and hold positions.
    Seems very sensitive to hold so I've been trying to get that consistant.
    I was thinking that I was wobbling all over the place but then I pick up the PCP and can plink at paddlepop sticks all day long.

    Testing only seemed to prove that choice of pellet still remains H&N FTTs but the grouping wasn't up to par - around half to three quarters of an inch.

    It's had at least a tin of pellets through it but didn't seem to be settling down.
    There was a whiff of dieseling and I thought it's about time I had a look.

    Opening it up, the first thing I noticed was when unscrewing the breech block, the threads seemed very dry.
    After it was apart I noticed a little bit of rust in there : (

    Onto the spring - looks OK but the ends need a polish.

    The spring guide is a bit of a sloppy fit, hence the twang. It's nylon, but not fitted to the spring.

    There's no top hat or piston washer in factory trim.

    The compression tube and piston both had light rub marks so they'll get a polish and a coat of moly.

    The piston seal had a bit of grease in front of it hence the diesel smell but otherwise it's in good shape.

    Tuning plans
    I'm going to re-use the original spring at this stage and get Matt to turn me up a decent guide and top hat to suit.
    We'll do a bit of polishing and then see if that doesn't tame the twang.

    Down the track I think I'll fit one of those Target Tune pistons but this stage 1 tune up will get things going.

    Stay tuned (pun intended) for the next installment when there's some polishing action.

    #2 GRMKC
    Posted 29 Jul 2013 - 11:46 PM
    Hey Nigel,

    I was interested in watching you strip and rebuild for the tune. Am I too late. PM me please. I'm strongly thinking about doing the same. Bugger the warranty. Shooting tight groups but the twang is starting to get to me.


    #3 mattw975
    Posted 30 Jul 2013 - 12:05 AM

    Was there much grease on the spring mate ?, the last two newish 97's I've looked at had no grease on them at all.


    Matt W

    #4 Chewtah
    Posted 30 Jul 2013 - 09:03 AM
    I had my ram o ringed, very spooky at first but too simple to do! Just take it to a machine shop and get a cap turned up in the shape of the seal with two o ring grooves in it. The machinist said it wouldn't need two but it looks the part.

    I think there would be room for one o ring at the other end of the piston too to stop it touching the cylinder.

    The lip that holds the seal on needs machining down so the cap fits over and then solder it on.
    #5 barradiction
    Posted 30 Jul 2013 - 09:42 AM

    Hi Geoff
    I have and album full of photos from stripping the trigger to replacing the spring if you're interested.

    Ferals Rabbits-12,Rats-21, Myna birds-4,pigeon-6,Cain toads -30+

    #6 Stones97
    Posted 30 Jul 2013 - 09:45 AM

    I also had slight rusting with the thread on the back block on mine
    .. And the same amount of grease on the piston seal

    Its certainly worth the strip just to address these issues.

    I fitted a V mach kit in mine , but im also getting Matt to make up new spring guide and a top hat for my 80.
    See how it goes..

    Good photos mate


    #7 mattw975
    Posted 30 Jul 2013 - 11:20 AM
    Interestingly I am reading a book at the moment on spring airgun theory.

    They tested a 12 fpe gun in air & then repeated the test in pure Nitrogen. The power dropped to 5-6 fpe, which means that the half the power was produced by the combustion effect of oxygen & grease (acting as an accelerant).

    So a slight smell of dieselling & a little bit of grease on the piston head is not all bad guys

    #8 Nigel-l

    Matt W,
    I would say there was an adequate amount of grease on it.
    Not too much.
    There was a bit much up at the seal end for my liking.
    Maybe the compression chamber could have done with a little bit more.

    #9 Nigel-l
    Posted 30 Jul 2013 - 11:36 AM
    Stones97, on 30 Jul 2013 - 09:45 AM, said:
    Its certainly worth the strip just to address these issues.

    Fully agree Brad,
    I wanted to shoot it a little bit first before tearing it down.
    I've got to know how it shoots in factory trim.
    However I'd recommend doing it sooner rather than later to address those few concerns.

    It wasn't up to it's full potential.
    You can see how much daylight there is in that spring guide picture - no wonder it was twanging.

    I've got a V-mach in my 80 and it's just so sweet to shoot.
    A new guide and top hat should settle it down nicely.
    They're just so much bigger then a 97 internally that they benefit from taming it down.
    I can't remember how many washers are inside mine but I think I'm going to strip it to pull them out.

    #10 Nigel-l

    I'll let you know when I'm rebuilding. Spring went off to Matt today to get a guide and top hat matched up.

    Yes bugger the warranty - You'll do more damage if these few little issues aren't resolved before the warranty runs out.
    You could shoot the shit out of the thing within the warranty period and all you'd have is a clapped out gun needing warranty repairs for the sake of a little bit of TLC.
    I was surprised by how much the compression tube had rubbed.

    Easy enough gun to strip.
    A few little things to be careful of.
    1 - After you punch out the pins to remove the trigger, make sure you don't lose the safety spring or the little nut at the back of the trigger block.
    2 - There's a little spacer washer under the stock lug that holds the anti bear trap in place - don't lose that one.
    3 - The breech block will need a firm tap with a hammer to loosen it up.
    4 - The spring has a bit of preload - take care when unscrewing the breech block.
    Either use a spring compressor or put your weight against it when unscrewing it - a pair of gloves will stop it from biting you.

    I'll send you a PM when the parts arrive.
    If you want a hand - let me know.

    #11 danny_h69
    Posted 30 Jul 2013 - 03:43 PM
    Well done Nigel! It looks like it was good timing to crack it open and have a look.

    I haven't worked up the courage to do the work myself... so...instead I had Matt tune up my HW97 for me

    I've just thrown a dozen pellets down it and I've got to say. WOW! What an improvement! The twang has gone, the action is smoother and feels quicker.

    Great job Matt!

    Matt does good work so I'm sure you'll be happy with the new guide and top hat he is making for you.

    Keep us posted with the tune up.


    #12 Nigel-l
    Posted 30 Jul 2013 - 03:58 PM

    They are really easy to work on so don't be afraid to give it a go. You couldn't do much worse than taking it to some so called gunsmiths.
    You're fortunate to have Matt readliy available - if I was up his way in NSW, I'd be around to annoy him.

    How was it shooting/grouping before the tune up?
    What's it like now?

    Looking at the amount of play in that spring guide I'm not surprised mine was vibrating all over the place.

    #13 danny_h69
    Posted 30 Jul 2013 - 04:33 PM
    Matt could probably explain what he found better than I can, but, basically he thought mine might have been a bit of a "friday arvo" job. (Which he found very unusual for a Weihrauch) He had just finished tuning someone elses '97 and said he could notice the difference in build quality.

    When I first bought it, I found it very difficult to shoot accurately (the shake, twang etc...) even off a bench/table. I hadn't shot in 20 years, but I read quite a bit on technique for springers and I tried to develop those skills. I'm an average shot, so shooting a high(ish) powered springer, having to pay attention to an 'artillery' hold and everything else.. just became too difficult. I could shoot my .243 better than the springer...

    I took it rabbit shooting a few times and managed to bag a few, but I think this was just the rabbits bad luck more than my skill. As a result I put it in the safe and virtually forgot about it. Then ended up buying a Marauder instead.

    I didn't get enough time today to really put it through it's paces, but it's MUCH better to shoot. Much more pleasant and forgiving with technique. The twangs gone and the shake is less noticeable and shorter. ie. it doesn't seem to shake for as long.

    As far as grouping goes it's a bit hard for me to say, because, I think the problem is mostly with me. When Matt gave it back to me he said he had a shoot with it and was getting 1 hole groups at 20m. I had a play with it at 20m and was getting the pellets touching, without the amount of concentration I had to use before the tune. I think with practice (not having shot it in ages) and a bit more attention to technique, 1 hole groups wouldn't be out of the question for me now.

    Anecdotally, I think it has improved the rifle quite a bit. Definitely worth the spend IMO, as I am going to use it far more often now.

    I hope all that makes sense...

    For anyone thinking of doing it I would say DO IT, you won't regret it. If you're like me and hesitant to have a go yourself, I'll give Matt his due, he does really good work.


    #14 Nigel-l
    Posted 30 Jul 2013 - 06:26 PM

    All makes sense.
    I couldn't figure out why I couldn't get a tight group and I understand how critical hold is.
    Glad to hear someone else's experiences and that it wasn't just mine. A good result should be readily acheiveable.

    All this discussion helps everyone understand how a good gun should perform and if it doesn't, it may need some help to reach it's potential.

    Upon stripping it down I didn't think it was too badly assembled, but there's obviously good and bad days at the factory.

    #15 kenny
    Posted 30 Jul 2013 - 08:15 PM
    Just got the 97 back from Matt. Bloody great , no twang, smoother cycle , a big difference. Only put a few shoots through her but I'm impressed. I will have a play tomorrow but I reckon I can get pretty decent groups out to 50 meters. We were knocking .410 shells at 30 meters with a crap centrepoint sight. Well done mate.

    #16 GRMKC
    Posted 30 Jul 2013 - 08:34 PM
    You lucky bastard Kenny. Like Nigel said, if Matt was in Vic, we would all be knocking on his door.

    As a matter of interest, are there enough of US out there to warrant a trip to Melbourne by Matt? I'm sorta in Danny's shoes as well. Trying to clear the workbench and grow some balls to do it. I'll get there. Bit of a squeaky voice at the moment though.
    #17 Nigel-l
    Posted 30 Jul 2013 - 09:39 PM
    You'll derive a lot of satisfaction from a bit of DIY.
    Get cracking.

    #18 mattw975
    Posted 31 Jul 2013 - 12:07 AM
    Thanks Kenny, it was fun.

    I'd be interested to see your 50M groups, at 30M it was grouping very well indeed

    #19 mattw975
    Posted 31 Jul 2013 - 12:17 AM
    Thanks Dan too

    The Weihrauch range really are well thought out from the maintenance perspective. Come on Geoff, its not that difficult to work on these

    Smoothing the shooting cycle out requires tight fitting guides, etc. The ideal is to have the gun to work on, but if distance is an issue sending me the spring to measure & make bits for is a close second.

    The key is building a tuning kit around the spring
    #20 Nigel-l
    Posted 31 Jul 2013 - 10:06 AM
    mattw975, on 31 Jul 2013 - 12:17 AM, said:
    Come on Geoff, its not that difficult to work on these />

    Tell you what Geoff, I'll even lend you my big hammer. />
    #21 GRMKC
    Posted 31 Jul 2013 - 02:11 PM
    And I though we gave Phil a hard time about buying an underlever AR................................

    #22 GRMKC
    Posted 02 Aug 2013 - 11:09 AM
    OK. Garage and workbench starts tomorrow boys. Been studying videos on Youtube. Looks easy enough. Already bought my punches.

    Stand back. Lunatic about to be let loose.
    #23 Nigel-l
    Posted 02 Aug 2013 - 11:29 AM
    GRMKC, on 02 Aug 2013 - 11:09 AM, said:
    Looks easy enough. Already bought my punches.

    Yes, but do you have a big enough hammer? />

    I'm going shootin' tomorrow, I'll check back on Sunday to see the pics of how you went.
    How much work do you reckon it's done? I reckon mine had about tin of pellets.
    I'd be interested to see if there's any rub marks on the tube and piston.
    • Delete
    #24 GRMKC

    Posted 02 Aug 2013 - 09:46 PM
    I'm starting with the baby brother first (HW95). Probably done about 2 tins. The start of 'works' is cleaning the damn garage first to sweeten the Missus.

    Then, we go hell for leather next week. that's the plan anyway. Good shooting.

    #25 Nigel-l
    Posted 14 Aug 2013 - 09:00 PM
    I got a package in the mail today.

    Looks a bit like this.

    #26 mattw975
    • Location: NSW
    Posted 14 Aug 2013 - 09:17 PM
    You did well to get those out of the spring, as they were very snug as a twang free set should be

    #27 mattw975
    Posted 14 Aug 2013 - 09:19 PM
    I hope you remember which way around they go as they have been sized for a specific end

    #28 Chewtah
    Posted 15 Aug 2013 - 08:13 AM
    When the Theoben got pulled apart I had a machinist make removable pin for the cocking lever, the peened in one gets loose with being taken in and out too often.

    Occasionally they work loose a rip great pieces out if the stock when you cock it, which is most cheery I can assure you!

    #29 Nigel-l
    Posted 15 Aug 2013 - 09:26 AM

    Very snug indeed.
    Yes there's a texta mark at the spring guide end.

    I did notice that even with the old one, the spring has a bit of a taper and it was tighter at the piston end when I took it apart.
    I was going to install the old one with the spring guide in the tighter end to see if it made enough difference.
    I couldn't be bothered putting it back together with the old parts when these were on the way.

    The closer Iook at the gun, the less impressed I am with the finish,
    My old HW80 which was made in the 80's has a better finish on all it's components.

    As I was polishing the piston, it revealed some minor pitting from a part that has had a bit of surface rust.
    There's even a little mark on the barrel that has been blued over.

    #30 Nigel-l
    Posted 17 Aug 2013 - 09:36 PM
    A few work in progress shots.

    Spring before and after.

    Piston polishing

    Tried to get one of the Compression chamber

    #31 mattw975
    Posted 17 Aug 2013 - 10:09 PM
    It always amazes me how crappy some AR spring ends are finished.

    It looks like they were finished with a chop saw rather than a grinder. And its pretty important to have good finishes on them to keep friction to a minimum

    #32 Nigel-l
    Posted 18 Aug 2013 - 11:39 PM
    An afternoon in the shed.

    Good degreasing session - I reckon the bluing is better for it.
    I think there could have been a touch of surface rust from when it was shipped.

    Thought I'd try giving the spring a coating of Lithium grease.
    Not entirely convinced.

    Moly applied to new guide and top hat.

    Moly coated piston and chamber.
    I thought this might take up a bit of the clearance without needing to button the pistion.
    There's still a little bit of slack that could benefit from careful attention.

    Ready for assembly

    Blue loctite should help keep everything in place.

    Ready for a test firing.

    #33 Whitey
    Posted 19 Aug 2013 - 03:13 AM
    Well you've convinced me to have a crack now. Thanks!

    #34 GRMKC
    Posted 19 Aug 2013 - 08:07 AM
    Hey whitey. When you decide to do it, maybe we organise one of the more exerienced guys to run a workshop so us novices know what to watch out for. I might be doing the hw95 but I'm going on Youtube videos of people pulling apart new guns and my own gut instinct.

    Good job Nigel.

    #35 Nigel-l
    Posted 22 Aug 2013 - 05:26 PM
    I've been waiting for a dry calm day to test this thing but it looks like it's not happening any time soon.

    I had a quick look at the weather radar and I saw a big blue band coming across the bay.
    So I snuck out for a quick half hour.

    Couple of sighters to check the scope - not too far out, couple of clicks left did the trick.

    Wind was blowing a bit so a tight group didn't materialise.
    But they do seem a bit tighter than before.
    Certainly the muzzle flip has clamed down a lot and the spring twang is noticeably absent.
    There's still a bit the twang from the underlever spring but then I didn't touch it.
    The addition of the top hat and thrust washer has increased the cocking effort slightly and I daresay the power a touch.

    Bring on a dry day.

    Before and after results

    Before Group.

    After Tuning

  • #2
    Experiments in Lubrication Part II

    You'll notice above where I tried some Lithium grease.
    And at the time I said I wasn't convinced as I thought it was a bit light.
    It turns out I was right.

    I'm happy with the performance from the new spring guide, getting one hole groups at 25 metres ( when I do my part).
    However there was still a bit of spring noise.

    Been considering this over the last couple of weeks and after a discussion with Geoff, I deceided to open it up to re-lube.

    The original stuff had stayed on quite well. I pulled the spring and guides out and wiped the old lube off with paper towel.
    Didn't bother to degrease as they were going straight back in.
    After a bit of testing in Autobarn while the sales staff weren't looking I came away with some sticky chain lube and some heavier grease.

    Sprayed the spring with the chain lube and let it dry.
    It becomes really sticky to the touch.
    Once dried, I gave the spring a coating of this new grease.
    Its still a Moly based grease but it feels a bit heavier than the other stuff I already have.

    Didn't remove the piston, Had a quick look at the molybond - it appears to be doing a rather good job.
    Just topped up the rear of the piston skirt with a little bit of this heavy stuff.
    Reassembled and did a test firing.

    No more twang.
    What's more, it's nearly silent to cock now. Not that it was noisy but it's super smooth now.
    Some paper punching in the morning if the weather's good to see if it has improved the grouping any more.
    I reckon it'll dampen the spring a bit more and perhaps tighten the groups further.

    Morale of the story.
    Spray on Lithium grease isn't heavy enough.
    Anybody want to buy a slightly used can of the stuff?


    • #3
      "For it is the doom of men that they forget"


      • Guest's Avatar
        Nigel-l commented
        Editing a comment
        This is another good one as well.


    • #4
      Originally posted by RoyaleR7" post=94316
      I found this vid helpful

      "For it is the doom of men that they forget"


      • Guest's Avatar
        Andy. commented
        Editing a comment
        Good vids, but padded workbench please! HW bluing is certainly deep and rich, but will mark if barrel and cylinder are constantly slid across a hard surface during a service.

        I also insert the breech block into the cylinder jaws on any b'barrel, lower side first to prevent marring to any visible blued parts of the block.

        Forget the paint brush, lube her parts up with a finger much faster and thorough IMO, your fingers are going to get greasy no matter what

    • #5
      I seem to remember TR Robb in the UK does a reaming tool exactly for that job.

      "For it is the doom of men that they forget"


      • Guest's Avatar
        Nigel-l commented
        Editing a comment
        Isn't that to open the port up a touch?

        I'm just talking about chamfering the edge and giving it a polish.