Hw35

[tuck1]

Good afternoon

I have spent several days searching for the answer to this one, despite finding a wealthy of other info I can't quite seem to nail this one.

Some years ago I bought, from a gunshop, a very well used and unloved HW35. The breech seal was in a bad way and the woodwork, and metalwork was poor too. The day after I got it home, a farmer friend borrowed it, so I never shot it. It has recently returned to me, and with the assistance of numerous posts on her, I have stripped and dismantled it. It is a leather piston seal version, single sided safety. The serial number under the barrel doesn't seem to match any dates I have seen, it's 721757, my guess is that it's late 70's? Any thoughts?

Anyway, now it's in pieces I've found it has a square section spring which was under considerable preload. It shot horribly, low power, high recoil, spring twang, very difficult to cock.I don't have access to a chrono (I know this is something that I'll need to address on re assembly) but the power was well down. I've replaced the breech seal, rejuvenated the piston seal in SM 50, and swabbed out the chamber with meths. It has the original spring guide. I've ordered a original mainspring from Chambers, which has arrived, and thus lies my main question...

The replacement, new Chambers spring is longer than the one which has come out (which I'm guessing is an Ox.) the old spring is 22.5cm long, and 26 coils. The new one is 24cm and 27 coils, so under even more preload. Am I right in thinking that the new spring is not a direct fit, and will need cropping/ refinishing first, or should I be trying it first, squeezing it in and then chrono and reduce by degrees until satisfied? This would be a problem as I will be taking it to a gunshop to chrono it.
Obviously being a hw35, I am more interested in a sweet shooting gun than high power levels.
This is my first attempt at airgun stripping and maintainence, and what an enjoyable project it has been so far. I can't wait to get it back together when my moly grease arrives.

Many thanks, in advance for your wisdom.

Adrian

[junglie]

My '77 35e makes 11+ ft/lbs on it's original standard spring & leather washer(rejuvenated with hempseed oil), it has very little preload ,maybe half an inch from memory. It's the only springer I own I've rebuilt without a spring compressor!

[tuck1]

Thank you. From memory can you remember how long your spring is?

[Heavy Roller]

Are you certain that there are no pre-load washers inside the piston?

[tuck1]

There doesn't appear to be, the spring inserts 9.5 cm into the piston.

[davymole]

you are right with the date being 1979,I just replaced a 35 with a weihrauch spring old new stock with 28 coils and round not square and a new leather washer and piston its at 11ft/lbs this had no preload at all .has settled down.the recommended Ox is a number 4 .this still uses the original spring guide.

[JLB]

The spring you have been sent appears to be the new Weihrauch standard spring fitted to most of their full power guns. I would fit it & then have it chronoed.

John