Weihrauch HW55

[deejayuu]

Good read here. Will try to do some dismantling/photos tomorrow.

[T 20]

Good read here. Will try to do some dismantling/photos tomorrow.

I'm intrigued for a couple of reasons, Jules.

Although Aluminium is about a third of the weight of steel per cc, the aluminium section of the piston head shown is about two times longer than that section on the all steel pistons --- hence my interest in the piston weight.
The long Aluminium section could just be long to allow enough thread engagement in the steel body, but then it's strength has been compromised by machining a slot into it --- weird.

The other thing I've noticed this morning is that the piston head appears to be an O ring conversion which probably accounts for the gun's consistency.





All the best Mick

[TonyL]

And I must get around to stripping my 55 one day (this won't be helping others on here)........bought about ten years ago from a very nice forum member. I wasn't actively seeking one but it needed buying! I only had a few shots with it and remember it being quite twangy but the recoil being very low. But it's lived in the cabinet ever since. Must pul my finger out and have a look inside. I could understand the use of aluminium to reduce the weight, but not convinced over its suitability vs good old steel. Is it sounding like these might indeed have an ally piston?

[robmc]

If anyone is junking an old piston with a damaged head but good tube I have a kidney here with your name on it....well not literally......don't think tatoo's go that deep...

I have a Hw55 piston,
I'd swap it for your kidney or £50 (whichever you prefer!)

I've sent you a pm and email with pics.
Regards,
Rob

[evert]

I'm intrigued for a couple of reasons, Jules.

Although Aluminium is about a third of the weight of steel per cc, the aluminium section of the piston head shown is about two times longer than that section on the all steel pistons --- hence my interest in the piston weight.
The long Aluminium section could just be long to allow enough thread engagement in the steel body, but then it's strength has been compromised by machining a slot into it --- weird.

The other thing I've noticed this morning is that the piston head appears to be an O ring conversion which probably accounts for the gun's consistency.





All the best Mick

The thing I dont understand is why they didnt extend the piston body all the way up to the seal.
That way there would be lot more threads uncompromised by the cocking slot.

[nick_mantis]

Weighed the piston tonight for those interested. And to be fair I have stripped it of any accessories that would alter it.

This is just for the:
Steel body
Aluminium head
Steel hook

Excluded:
Piston seal
Washers/brass spring seat
(basically anything that can change from rifle to rifle)

Total Weight: 149.48g Allow a tiny bit extra for a tiny amount of missing material but I would reckon 149.50g for these pistons.