Hw 77 Tinkering

[AirTinker 8]

Hi All, Hope this is allowed on this forum. 

First post so apologies if the photos don't come up as planned... 

 

I acquired a second hand .22 hw77 from a local RFD last year between lockdowns that was sold as not working, finally got round to to getting it apart this week and trying to sort it.

Overall the gun wasn't in bad condition. The blueing is ok for its age, the stock needs refinishing but thats fine, for now I have stuck on a thumbhole synthetic stock I had spare. It came without a scope but with a slip on silencer with 'AirMasters' written on the side. The issue was that the gun wouldn't cock. When I stripped it down, inside there was a large square section spring and alot of preload. Not a fan of the square springs anyway so I ordered a new standard spring from one of the gunspares websites and it arrived 2 days later.

Whilst apart I decided I would try and 'Glide' the piston assembly.
The 77 came with a 25mm piston setup, but I had a spare 26mm version that I have used first as a trial piece. I haven't done a 77 piston before, my only experience adding bearings has been with a hw95 and that was pretty straight forward.

First step was to reduce the overall length of the compression tube so that I could fit a rear delrin bearing to the piston skirt followed by turning up a small steel spacer that was pressed onto the end of the piston.

I then gave the piston a sandblast to remove any of the dirt that was present and give it a matte finish. I also gave the comp tube a quick tidy up as it had scuff marks from where it has been used over time.

Next was turning a couple of delrin pieces to add onto the front and rear of the piston. Whilst i was already turning delrin I also made up a spring guide / top hat to fit onto the new spring + cut out a ptfe sleeve to sit between the piston and spring.

 

Installing it back into the hw77 was pretty simple. There was a small amount of preload but no where near what came out when it was taken apart! I had to remake the rear delrin bearing as it got scuffed when going back in, no bother though. I gave the inside of the 77 a good deburr before trying again. Removing the sharp edges in the cocking slot and the hole where the rear lug screws into, this time it went in with a very smooth fit.

 

The piston and comp tube aren't quite finished yet. The plan is to put them through the blacking tanks at work just to be a little different. May just black the compression tube im undecided. Once im happy with the results the next stage is to do it all over again with the 25mm set up and stick the 26mm set in the draw somewhere safe. May be an excuse to buy another 77/97 just to use it.

Just a photo to show the spring length differences!

 

To anyone who has done this before, out of curiosity what sort of size did you make your bearings fit inside the 77?

I dont know if i went to tight or not. I went for a interferance fit and then carefully took them down with 400grit until they slided foward and back smoothly. I ended up with the front at 25.90 and the rear at 29.94 (rounded up/down using a digital mic)

Also would it be worthwhile to add something to the compression tube? From what ive read this will/may only improve cocking is that correct?

I also posted this on another forum also as im looking for any good ideas to improve. 

Have to say TheHuntingLife forums are what got me interested in doing stuff to air rifles many moons ago when i was still a kid. Ive gone by a few usernames since then but mostly just read through. Think theres a sticky in the rifle reviews, technical help & tips sections from my old account when i was around 12 / 13. 

Any advice on more tinkering greatly appreciated. All the very best 

 

[villaman 9,983]

Welcome to the best forum & of course it is allowed, it’s not like the airgun forum or bbs .

what a first cracking post by the way 

[AirTinker 8]

38 minutes ago, villaman said:

Welcome to the best forum & of course it is allowed, it’s not like the airgun forum or bbs .

what a first cracking post by the way 

Hi thankyou for the welcome! 

Atvb 

[Rez 4,961]

I second v’mans comment. Bangin first post babe.

Ain’t even read it yet but it just looks a decent read. How the f’k are you new to the forum working on manual rigs like that? You don’t just do all that out the blue... so you must have been doing it for sometime AND you never thought... ‘I wonder if there’s any airgun forums out there?’

You got that 77 sat in a blackline stock? 

[Dervburner 2,549]

Good work tinker, looks like you know what you’re doing anyway. It will be interesting to see how it performs fella.

[AirTinker 8]

Thankyou! Ive been tinkering with air rifles for quite a while! Im quite lucky really I get a bit of work for Airguns through my job.

Yep its currently sat in a black synthetic thumbhole stock, made for the 97k I think. I need to get around to restoring the wooden stock it came with so I just used that synthetic one so I could get it all back together looking like an airgun again. Got 2 77/97 stocks and a couple others to fix up so going to spend a weekend sorting them all out together at some point.

Good news is we're going to be firing up the blacking tanks at work either end of this week or next week so should get it finished and looking the part soon! Bad news is ive got to take it all apart again. Took it out for a try already and it does shoot good! Dont think il bother adding any to the compression tube. 

Tempted to machine a steel rear guide and install it into the back block like the old vglide 77's just to see the difference, but if I dont like it then its quite the commitment, opening up and threading the back block.  

 

Will stick up a couple of pics of the finished product when its done!

 

Atvb 

[shaaark 10,876]

48 minutes ago, AirTinker said:

Thankyou! Ive been tinkering with air rifles for quite a while! Im quite lucky really I get a bit of work for Airguns through my job.

Yep its currently sat in a black synthetic thumbhole stock, made for the 97k I think. I need to get around to restoring the wooden stock it came with so I just used that synthetic one so I could get it all back together looking like an airgun again. Got 2 77/97 stocks and a couple others to fix up so going to spend a weekend sorting them all out together at some point.

Good news is we're going to be firing up the blacking tanks at work either end of this week or next week so should get it finished and looking the part soon! Bad news is ive got to take it all apart again. Took it out for a try already and it does shoot good! Dont think il bother adding any to the compression tube. 

Tempted to machine a steel rear guide and install it into the back block like the old vglide 77's just to see the difference, but if I dont like it then its quite the commitment, opening up and threading the back block.  

 

Will stick up a couple of pics of the finished product when its done!

 

Atvb 

I won't even pretend to make out I understand all the technical tuning stuff lol, but I'm keen to see how you get on with this project.  Sounds good to me mate

[JakeFury 225]

Yeah very interested in what you've done to the piston. Working on some 97 developments of my own at the mo. 

 

[Dervburner 2,549]

12 hours ago, JakeFury said:

Yeah very interested in what you've done to the piston. Working on some 97 developments of my own at the mo. 

 

Nah.....ditch that and get yourself a nice supersport

[JakeFury 225]

This is a very enlightening thread for me. It goes against some developments I've been working on. 

Would love to exchange some ideas

[AirTinker 8]

20 hours ago, JakeFury said:

This is a very enlightening thread for me. It goes against some developments I've been working on. 

Would love to exchange some ideas

Well feel free to message me if you have any questions about what ive done so far! Ive done a fair few 77's / 97's now and the ones ive ended up selling (always end up selling an airgun only to rebuy the same model again at a later date  ) have had nice feedback. 

Currently the project 77 is on pause as im waiting for the blacking tanks at work to be fired up again so i can send my parts through with the work stuff....   

Was hoping it would be this week but its looking like next week now as we only work Mon - Fri. 

I also have a spare Hw97 mk1 action sat in my cuboard of bits, the one where the silencer sticks out further than the underlever. Once finished doing both the 26mm set up and the 25mm piston set up i might bring the 97 back to life aswell as its been stored for a while now. Have all the parts to rebuild it except for 1 trigger guard and the lug that screws into the action, then the trigger screw, screws into that, dont know its name. Might just make one whilst waiting for the blacking of the comp tubes. 

To be continued... soon hopefully!

Atvb 

 

 

[johnbaz 363]

Oooh!! You did a great job there AT 

 

I traded some stuff for a 77k action that was quite honestly, A mess!!

I already had a 97 sporter stock spare, The action was described as being very good condition, In reality there was rust, The cocking underlever had been bent and hammered straight by the look of it and the cocking link was kaput- Also, There was no trigger with it, I had an old Rekord unit with the laminated long sear but the rifle wouldn't work with a safety, I think the trigger was made for the early guns that didn't have a safety but I lost interest. I think it just needed a part bending to make the safety work!

I also had the Venom type mod/catch spare but didn't fit it..

 

The cocking link was almost cracked through, The hook had worn completely off, I looked on fleabay to no avail and Protek had none in stock so I got thre welder out..

After making up with weld and cutting the notch out..

 

I cut a mainspring to size (The size I cut it to was too short!!) and dressed the end, It's only shooting at around 8ft lbs 

Now i've retired from working I may muster some enthusiasm to get another spring inside, May even strip the action for a reblack 

 

John 

[Cat Fluff 0]

Hello - I also have a 77 which I cleaned today by removing the action from the stock. Putting it back together via the trigger unit and fore-end I noticed that initially although it fired, the safety did not engage - I could fire it straight away. Now, it's cocked but wont fire at all. Ive not done anything to the trigger unit at all. It was fine before I took it away from the stock to clean it. Any ideas greatly appreciated!

Thank you.
Paul.

[philpot 5,005]

Welcome aboard Cat Fluff (a name that is strange to say the least ) this thread is 3 years old and the guy has not been on here since so I don't  think he will respond. Feel free tp join in with us though.

Phil