HW99 Piston Dimensions required ?

[robs5230]

Long story, Rob.

I always fancied having a go at tuning an Oldschool HW50 after Jim showed his Venom tuned one in Airgunworld many years ago.

So I bought a nice HW50 off Mach 1.5 but it was a bit too good for me to mess about with, so I put that one in the gun cabinet.
Then I bought a HW99 stock off here from Rincewind.
Then I bought an action from Jonny Neate that he'd bought off the bay, but this turned out to have a buggered barrel.
Then I bought a HW99 barrel off someone at the Boinger Bash.
Then I bought another cheap HW50 off Mach 1.5 but decided to stick that one in the cabinet as well.

So I've now ended up with two HW50s and a big pile of HW50/99 parts to mess about with and put together, but that's a bit too easy so I'm aiming on stroking the poor little thing from 65mm up to 75mm to get her nearer to 12ftlbs for ratting duties.




All the best Mick

Sure you'll get it sorted

[T 20]

Sure you'll get it sorted

The trick is to get it sorted as quickly and as cheaply as possible, Rob.

Some of the guns I've built owe me over a weeks wages.




All the best Mick

[brk1]

No problems Mick

Sounds like you had the same but different scenario that I did . I got an old 99s as a lockdown project at the start of lock down (very first one) , I accumulated enough bits and pieces over time trying to build another 99s so I had a .177 and a .22 version, I never managed to complete that gun, I never managed to get the cylinder and the back block/trigger block to be able to complete it, when I got the first gun , there on auction site was a broken for spares 99 , cylinder for sale and the trigger block as well, I didn't want them then, so typical , never seen those parts since , eventually I got very lucky and got a 4 month old complete 99s that was cheaper than the lockdown project was . So now I have both guns.

I'll still keep my eyes open for those missing bits . I'm still missing the cylinder , the trigger block the trigger pins to hold it to the block and one stock screw , but that depends what model it is , some use 6mm some use 7mm . I like the shot cycle of the .22 , but all my other guns are in .177 , so I still have a choice as to final 99 configurations , either one of each or 2 x .22 or if I ever complete my parts search I'll have the .177 and 2 x .22 as well , I'm in no hurry at all . I actually made myself a stock to fit one 99s and got another one nearly new fron the bay

Are you trying to build some custom version of the gun?, the HW50 is the European version of the HW99s or so I was led to believe, they easily make 12 FPE , in fact if you have a seal fail that sucks a bit of Moly through they make 23 fpe without even a bang If your building a .22 , they easily make 12 even with a soft Titan No.10 in them

[evert]

Are you trying to build some custom version of the gun?, the HW50 is the European version of the HW99s or so I was led to believe, they easily make 12 FPE , in fact if you have a seal fail that sucks a bit of Moly through they make 23 fpe without even a bang If your building a .22 , they easily make 12 even with a soft Titan No.10 in them

Theres always confusion around the HW50...

The current HW50 is as you say the same gun as the HW99, and both are easily capable of 12fpe.

The older HW50, which is the one Mick is working on, is a older discontinued model with a 25mm cylinder and a shorter stroke.
Think of it as a sporter version of the HW55 target rifle.

[T 20]

No problems Mick

Sounds like you had the same but different scenario that I did . I got an old 99s as a lockdown project at the start of lock down (very first one) , I accumulated enough bits and pieces over time trying to build another 99s so I had a .177 and a .22 version, I never managed to complete that gun, I never managed to get the cylinder and the back block/trigger block to be able to complete it, when I got the first gun , there on auction site was a broken for spares 99 , cylinder for sale and the trigger block as well, I didn't want them then, so typical , never seen those parts since , eventually I got very lucky and got a 4 month old complete 99s that was cheaper than the lockdown project was . So now I have both guns.

I'll still keep my eyes open for those missing bits . I'm still missing the cylinder , the trigger block the trigger pins to hold it to the block and one stock screw , but that depends what model it is , some use 6mm some use 7mm . I like the shot cycle of the .22 , but all my other guns are in .177 , so I still have a choice as to final 99 configurations , either one of each or 2 x .22 or if I ever complete my parts search I'll have the .177 and 2 x .22 as well , I'm in no hurry at all . I actually made myself a stock to fit one 99s and got another one nearly new fron the bay

Are you trying to build some custom version of the gun?, the HW50 is the European version of the HW99s or so I was led to believe, they easily make 12 FPE , in fact if you have a seal fail that sucks a bit of Moly through they make 23 fpe without even a bang If your building a .22 , they easily make 12 even with a soft Titan No.10 in them

It's a bit strange isn't it, there used to be HW99s being broken for parts and sold in sales on a regular basis but I can't recall seeing one for a couple of years now.

The HW50 I'm trying to sort is pre HW99/50s so is a completely different animal.




All the best Mick

[TonyL]

It's a bit strange isn't it, there used to be HW99s being broken for parts and sold in sales on a regular basis but I can't recall seeing one for a couple of years now.

All the best Mick

It's 'coz loads of peeps is finally feeling the lurve for the 99 and keeping 'em, Mick.

[Hsing-ee]

I keep toying with the idea of stroking one of my old school HW50 rifles, the deal is you remove 3mm from the back block and change the cocking lever to a modern HW99 one and then .... what? Stick a HW30 piston in it and cut the cocking slot back?

[brk1]

Thanks for explaining it guys , I've only come back to airguns in the last 3 years or so , didn't know the old HW 50's were different from the modern day version hence me asking why , I didn't think Mick was a newbie to airguns one little bit, so couldn't fathom out why he was trying to get it to 12 fpe . As TonyL says little 99's are having a real purple patch at the moment, some people asking more for them second hand than what you get them new for , becuase they've thrown a Mickey mouse scope on top and the general shortage of new units , it isn't worth brand new gun prices in my eyes . Happy HW50 building Mick

[T 20]

I keep toying with the idea of stroking one of my old school HW50 rifles, the deal is you remove 3mm from the back block and change the cocking lever to a modern HW99 one and then .... what? Stick a HW30 piston in it and cut the cocking slot back?

As far as I know the HW35, HW50, HW55 and HW99 all use the same length cocking levers with the same Chambers part number of UL068 --- the plastic insert lever just superseding the steel roller lever.

The HW99 achieves its longer throw of the cocking lever by having the cocking arm pin 3mm further forward of the breech bolt than the Oldschool HW50.




All the best Mick