HW50 the original version. Spring option

[T 20]

Restoring a 1993 HW50, 22 cal, so the last of the line with a screw in end block. What spring is recommended? I'm thinking a factory 99 spring? Mach 1.5

Having just measured a HW50 piston yesterday.

The internal diameter of the synthetic sealed Oldschool HW50 piston is 20.5mm which works well with the 20.2 mm spring I have fitted at present.

This 20.2mm x 3.1mm size spring also allows the use of a reasonably thick walled standard HW nylon spring guide, using a 19mm OD spring would mean (to me) using a custom made steel spring guide.

[TonyL]

Brilliant. Thank you for this, Mick.

I'm thinking the next rifle of mine up for a fettle will be the '50, so this is invaluable information. Assuming that mine is a synthetic seal model and the piston dimensions are the same......I had a quick look at the Protek site at their Meteor spring and that one isn't going to work. At a cursory glance at the Mainspring Data Thread, the Titan No.7 might fit the bill? I'll have a proper delve into it later. Still wondering if a TbT kit for a '30 might work, but I'd have to look at the dims.....
And, I do like the standard, later nylon HW guide, so if I can source a spring that ticks the boxes on piston and guide fit, it'll just be a top hat to source.

[TonyL]

Got this off a bagnall and kirkwood listing



Model Outer (mm) Inner (mm) Thickness (mm) No. Coils (mm) Length (mm)
No. 1 21 14.5 3.25 31 280
No. 2 22.7 15.5 3.65 30 291
No. 3 20.8 14.73 3.26 34 304
No. 4 22.62 15.64 3.65 28 252
No. 5 19 13.19 3 32 290
No. 6 19.7 13.3 2.92 39 341
No. 7 20 13.8 3.3 30 255
No. 8 20 13.8 3.3 34 295
No. 9 21 14.75 3.3 27 280
No. 10 21 14.8 3.1 27 230
No. 11 18.8 12.8 3 31 230
No. 12 18.912.6 2.9 36 295
No.13 19.4 13 3.1 39 340

No.14 22.7 15.4 4.12 37 356

No.15 17.53 12.1 3 33 254
Hatsan 19.55 13.4 3.0 37 310mm

5/25 12.5 9.5 1.6 28 240mm

What would your thoughts be on the No. 7, Mick?

[T 20]

What would your thoughts be on the No. 7, Mick?

Those numbers don't add up, Tone.

20 - (2 × 3.3) = 13.4 not 13.8 --- perhaps it's a typo and it should be 3.03mm ?

Ideally you want 20mm OD with a 3mm wire, this will give 0.5mm total clearance inside the piston for a thin piston sleave and will fit onto a standard 14mm OD Weihrauch nylon spring guide.

Measuring the spring I'm using in my 12ftlb 70mm stroked HW50 today it's 20.2mm OD with 3.09mm wire and is 200mm long with 24 coils and 23 spaces --- and it does look like a Titan.

I found another simular spring in my collection which is indeed 20mm OD with 3mm wire --- this also looks like a Titan. So now I'm all set for machining up another HW50 piston.

[Mach 1.5]

Thanks Mick for that info. Gives me an idea for the spring to give my 55 more power and before all the 55 fans go oh no..the 55 is built on the 50 platform. Mach 1.5

[TonyL]

Brilliant stuff, Mick; thank you. I'll be referring to this when I work on my '50.

[TonyL]

Those numbers don't add up, Tone.

20 - (2 × 3.3) = 13.4 not 13.8 --- perhaps it's a typo and it should be 3.03mm ?

Ideally you want 20mm OD with a 3mm wire, this will give 0.5mm total clearance inside the piston for a thin piston sleave and will fit onto a standard 14mm OD Weihrauch nylon spring guide.

Measuring the spring I'm using in my 12ftlb 70mm stroked HW50 today it's 20.2mm OD with 3.09mm wire and is 200mm long with 24 coils and 23 spaces --- and it does look like a Titan.

I found another simular spring in my collection which is indeed 20mm OD with 3mm wire --- this also looks like a Titan. So now I'm all set for machining up another HW50 piston.

Do you think the "Junior Rifle Spring" listed here on the Protek site might be a good one then, Mick? :-

Sorry for separate post, I couldn't paste the link onto this.

Some useful looking springs there, methinks.

[TonyL]

http://www.proteksupplies.co.uk/mainsprings.html

[T 20]

http://www.proteksupplies.co.uk/mainsprings.html

That looks a perfect match for the spring I'm using, Tone.

I'll grab the new spring I've found and measure at 25.5 coils to see if the spacings compare, I'll also measure the cocked spring room of a standard 50.

I couldn't say if it'll work well in a normal stroked 50 though, it's probably best to pull your spring to see what you have before ordering.

Edit :-

From my rough sketch of a 50 piston you have at least 105mm of spring room when cocked.

[T 20]

Thanks Mick for that info. Gives me an idea for the spring to give my 55 more power and before all the 55 fans go oh no..the 55 is built on the 50 platform. Mach 1.5

The HW55MF was a complete HW50 action dropped into a target stocK, Paul.

There is a question mark over the HW55 pistons though as I've read that some are different to a HW50 piston, being made of steel and aluminium.

[TonyL]

Yes, I'm sure I'd read something along those lines on an older thread, Mick.

[TonyL]

That looks a perfect match for the spring I'm using, Tone.

I'll grab the new spring I've found and measure at 25.5 coils to see if the spacings compare, I'll also measure the cocked spring room of a standard 50.

I couldn't say if it'll work well in a normal stroked 50 though, it's probably best to pull your spring to see what you have before ordering.

Edit :-

From my rough sketch of a 50 piston you have at least 105mm of spring room when cocked.

Brilliant! Thank you for taking the time to look into this, Mick, and confirming the potential compatibility. As you say, I'll not get ordering anything until I strip it and have a measure up.

I also wonder if these might be of use in a '30.

[evert]

The HW55MF was a complete HW50 action dropped into a target stocK, Paul.

There is a question mark over the HW55 pistons though as I've read that some are different to a HW50 piston, being made of steel and aluminium.

Mine just says "HW55 M".

[TonyL]

Thanks Mick for that info. Gives me an idea for the spring to give my 55 more power and before all the 55 fans go oh no..the 55 is built on the 50 platform. Mach 1.5

I have many higher powered rifles, so wouldn't be chasing power on my 55, preferring to keep it as Hermann intended. But I'd never question anyone for wanting to do so. I think Ivan and Dave did some higher powered 55s, didn't they, Paul? And I know Steve fancied getting one and having a play. Did he ever manage to get one?

[T 20]

Those numbers don't add up, Tone.

20 - (2 × 3.3) = 13.4 not 13.8 --- perhaps it's a typo and it should be 3.03mm ?

Ideally you want 20mm OD with a 3mm wire, this will give 0.5mm total clearance inside the piston for a thin piston sleave and will fit onto a standard 14mm OD Weihrauch nylon spring guide.

Measuring the spring I'm using in my 12ftlb 70mm stroked HW50 today it's 20.2mm OD with 3.09mm wire and is 200mm long with 24 coils and 23 spaces --- and it does look like a Titan.

I found another simular spring in my collection which is indeed 20mm OD with 3mm wire --- this also looks like a Titan. So now I'm all set for machining up another HW50 piston.

Reading this again it read like a right load of old bollocks, so I've slapped her back together again (twice) and run her over the chrono.

After washing the cylinder out, the first time I put her back together with Walther piston lube, with this the piston seal felt tight so I stripped her and washed her out again.
Then I burnished some dry slide in the cylinder walls and changed the piston lube to the molly that I normally use and away she went 590fps with .22" superdomes 650fps with Hobby.

I've lost 20fps just by stripping the gun and putting her back together, but I expect her to bed back in after some use.

The bit that made me wonder was the 200mm long spring, it didn't sound feasible, but looking at the spring data thread I noticed that the TX MK2 only used a 200mm long spring.

So all good again.