Cedric 132 Posted August 21, 2014 Report Share Posted August 21, 2014 My new HW99S was underpowered from the start so I polished and re-lubed the internals still only getting about 9ftlbs. I ordered a Titan #1 spring (their recommendation for the 99) but it was too wide to fit in the piston with a sleeve in place. Original spring 20mm O/D, Titan #1 21mm O/D. I did try thinning the Titan down a bit but it wasn’t successful. So I looked through Titan’s list and ordered a #7 , 19.5mm O/D with wire 0.05 thicker than the #1, slightly less I/D. Fitted it today (without any cutting). It took a fair bit of effort to cock and fired with a bit of a jump – however it only produced 8.8ftlbs! I’m stumped. Where do I go from here? I’d much rather fix it myself than send it off. Quote Link to post
mattybugeye 885 Posted August 21, 2014 Report Share Posted August 21, 2014 (edited) Had simular issues myself got mine to 10.7 today was trial and error like but ended up with original spring homebrew sleave delrin top hat made from spare delrin guide (gives about 3 mm to top of spring x2 1 mm stainless washer above the top hat and around 5 mm of delrin pre load washers not a lot I know but done the trick took a shave off the piston seal with very fine sand paper so glides nicely now de greased all factory grease used lt2 on spring and ptfe based silicone on seal just 1 or 2 drops and shooting nice now .what caliber is yours? My next port of call was to add a tx200 piston weight but 10.7 will do me Is your breech seal in good nick? Edited August 21, 2014 by mattybugeye Quote Link to post
mattybugeye 885 Posted August 21, 2014 Report Share Posted August 21, 2014 (edited) Only other thing I can think is shorten the spring a fair bit and pre load a lot ?? Just stripped mine down again this what it now looks like inside mate Edited August 21, 2014 by mattybugeye Quote Link to post
Cedric 132 Posted August 21, 2014 Author Report Share Posted August 21, 2014 Matty - calibre .177. New breach seal. The original spring with about 6mm washers brought it up to about 10 ftlbs. so the idea of shortening the Titan and adding preload might work. I think the spring is not far off fully compressed just now. I'll have to get a new spring guide as I've thinned mine down to fit inside the Titan spring ! Anyone know where I can get short lengths of Delrin bar stock, I might be able to turn myself some guides and top hats. Quote Link to post
mattybugeye 885 Posted August 22, 2014 Report Share Posted August 22, 2014 It's a head blag isn't it Not sure where to buy delrin but I've got this is any use to you ? You will need to shape the bottom to suite like but the shape is almost there Quote Link to post
Cedric 132 Posted August 23, 2014 Author Report Share Posted August 23, 2014 Thanks for the offer, what material is it? Someone else suggested that it might be 'oversprung' with the Titan spring so I had another bright idea . Rather than just shorten the spring I was thinking of collapsing a few coils and fitting it that end into the piston with the theory that not only would it reduce the spring power (it's just about fully compressed at the moment) but would also add a piston weight i.e, the collapsed mass of the coils. Anyone ever tried this and is it feasable? Quote Link to post
mattybugeye 885 Posted August 23, 2014 Report Share Posted August 23, 2014 It's black delrin mate Quote Link to post
Coypu Hunter 486 Posted August 23, 2014 Report Share Posted August 23, 2014 The only thing I could suggest is trying a Maccari spring. They're very supple and smooth, but very long -- you'd need to set it to get it to fit in the rifle, but that's easy enough to do. Cost just under £20 shipped from the USA, take about ten days to get over here. http://www.airrifleheadquarters.com/catalog/item/251488/1979288.htm Quote Link to post
Cedric 132 Posted August 24, 2014 Author Report Share Posted August 24, 2014 Matty, I tried to send you a message about the delrin but iot said you couldn't recieve any new messages ? Quote Link to post
mattybugeye 885 Posted August 24, 2014 Report Share Posted August 24, 2014 (edited) Inbox empty mate. If you want it pm me your address and il gift it to you to help with your project Edited August 24, 2014 by mattybugeye Quote Link to post
Cedric 132 Posted August 24, 2014 Author Report Share Posted August 24, 2014 Thanks, message sent. Quote Link to post
Cedric 132 Posted August 24, 2014 Author Report Share Posted August 24, 2014 Coypu - I've ordered a Maccari spring - see how it goes ! 1 Quote Link to post
Coypu Hunter 486 Posted August 24, 2014 Report Share Posted August 24, 2014 Coypu - I've ordered a Maccari spring - see how it goes ! Do you have a spring compressor? If not, you're fecked... But I'm sure you have some threaded steel rod lying around. Put the spring over the rod, put a washer either end to protect the spring, add nuts, tighten until the coils touch, and the spring will be set. You should then be able to get it into the rifle without contracting a hernia or having to chop down the spring. Let us know how you get on. Quote Link to post
Cedric 132 Posted August 24, 2014 Author Report Share Posted August 24, 2014 I have a rigged-up spring compressor, works very well, different shaped blocks for different rifles. Just an old sash clamp! 1 Quote Link to post
mattybugeye 885 Posted August 24, 2014 Report Share Posted August 24, 2014 Looks just the job . I use a sash clamp too 1 Quote Link to post
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.