AirGunTech: Re Engineering Spring Powered Air Rifles for smoothness, consistency, and to better suit UK power levels.

Update on the HW95 tuning

Its been a while…remember this post?

Well Its been on the back burner for a while and I decided I have had the rifle long enough here and should be getting it finished. Specs for the build were exactly as I outlined in the post above except for the transfer port, this was opened to 3.6mm over 3.3mm.

Spring was to spec above, I had to make a fresh guide and tophat for it as its smaller ID than the OEM spring…the result with approx 50mm of preload is bang on the money. Tested pellets werte Daystate Li’s (Crosman Premiers), Superdomes, Geco and Hobby and RWS Superfield. 10 pellets of each weas pushed thru the gun and then 10 shots over the chrono…10.8 to 11.1 with all of them, highest seen velcity was 11.3fpe and this dropped once the rifle settled with the pellet under test. Recoil is light, very little surge…its actually quite nice to shoot and I will range test it to see how it settles…right now im quite pleased how it came out and for me a blueprint tune is now set.











  • Hi there tony love the site very good reading forgive me if i have missed this on a previous post but what caliber 95 is this you are working on. I have a 177 and would really like to do this mod myself. I am competent enough to do the machining and follow the calculations any advise or tips would be greatly appreciated as this would be a first for me.

    Kind regards look forward to reading more of your posts

  • Just a thought but wondered if an LGV piston with the rear bearing machined down and a vortek 26 seal fitted might make a suitable donor for the HW 95 allowing the piston to rotate ? Haven’t seen one in the flesh so don’t know if the mushroom ‘socket’ is the same for 25/26 mm seals or if the OD of the piston body would allow the cocking shoe (perhaps slightly modded) to work with it.

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