Hold sensitive springer Update

[robs5230]

Problem comes when you reduce the stroke without reducing piston weight. Many of these factory long strokes have heavy pistons, as you need to stop the bounce those long strokes would give you. For the TX, a piston weight of 200g and a stroke around 83mm is very sweet. So that means throwing the piston weight away (around 35g), and ideally skimming a further 30g off the piston.

As for your 95 experience, that's unnusual... Witness the following the HW99s has on here, with it's 73mm stroke (26mm bore).. short stroking the 95 from 86 to 76 (same 26mm bore) brings it close to the 99 spec, job done.

The metal weights did come out of the TX pistons but no further weight reduction was done on the piston. The TX comment was really a mk2 / mk3 comparison. I genuinely think the mk3 had a nicer cycle.

I've had a 99 (got it from Nick actually and admittedly shot very well). Short stroking my 95 certainly didn't make it feel like the 99 but the 99 I had was .22 and the 99 has a longer barrel than the current 95. My 95 ended up shooting like a peach though. i'd say as well as a well sorted 99.
The mk1 85 I currently have has the longer 16" barrel which makes power far easier with oodles less spring. Maybe I need to try a SS extension in that as I have a spare spring.

[tinbum]

Regarding piston weight; a 10mm extension weighs 6 grams, the average factory fitted weights removed on fitting are 13 grams.

[cooper_dan]

Actual recoil is too difficult for most of us to measure. But it would be interesting to see how the efficiency changes with the different strokes. That's much easier to measure.

For example my tx MK3 was about 35% efficient. When I swapped to MK2 internals efficiency was up to 40%
I would guess that in this case the efficiency is rising as you get close to the optimum stroke (for this barrel/TP etc). As you decrease stroke even more the efficiency will go back down again and you will end up putting loads of pre-load in to keep the power.

Same deal with piston weight. If I had more time and equipment I would love to experiment with this. Test different piston weights at different strokes and come up with some kind of 3d graph showing where the efficiency peaks. Could also add in TP diameter to go the next step.

[bozz]

Hi can some one please answer me one question. I assume that Weihrauch must read these forums so why oh why do they not make a rifle that is "tuned" right out of the box, would it not make sense to do this and improve there market share and peoples thoughts of what is supposed to be one of the market leaders. Sorry its more than one question but, why dose the work have to be by the end users I can see it would upset the small tuners out there who have done fantastic work. So any way rant over just thought I would put my thoughts on the forum. Take care and enjoy your shooting while they allow us to. Graham.

[Shed tuner]

Hi can some one please answer me one question. I assume that Weihrauch must read these forums so why oh why do they not make a rifle that is "tuned" right out of the box, would it not make sense to do this and improve there market share and peoples thoughts of what is supposed to be one of the market leaders. Sorry its more than one question but, why dose the work have to be by the end users I can see it would upset the small tuners out there who have done fantastic work. So any way rant over just thought I would put my thoughts on the forum. Take care and enjoy your shooting while they allow us to. Graham.

they make their guns for export markets with higher power levels, and just "de-tune" by fitting a weedy spring, as it's cheaper than doing it properly

[robs5230]

Hi can some one please answer me one question. I assume that Weihrauch must read these forums so why oh why do they not make a rifle that is "tuned" right out of the box, would it not make sense to do this and improve there market share and peoples thoughts of what is supposed to be one of the market leaders. Sorry its more than one question but, why dose the work have to be by the end users I can see it would upset the small tuners out there who have done fantastic work. So any way rant over just thought I would put my thoughts on the forum. Take care and enjoy your shooting while they allow us to. Graham.

They must have assessed that their current market share is enough for them.
They haven't managed to cure the HW99 galling yet and seemingly have no intention of doing so.

If they keep selling their rifles as they see fit to turn them out, why would they ever want to increase quality ? All I've seen in recent years from Weihrauch is a downturn in quality.

[les allam]

I have had a shoot today with the stroke reduced Hw98, The gun is still super smooth and and is nicer to shoot with.There is less felt recoil and surge and I am finding it easier to group with.
The gun had a 86mm stroke, but is now 76mm stroke with the extension fitted.There is 1" 1/2" preload with no pre load washers fitted, and is doing 11.2 ftlbs with Jsb exacts..
Well pleased from Barking.
Atb
Les..

[dtdukok]

Sent mine to Nick Thursday, getting it back today. I’ll get it back together and see how mine feels.

Looking forward to it.

[dtdukok]

Update... I have to say not any noticeable difference in the cycle or recoil department.

What is different though is that I’ve lost power. I’ve now added all the washers/spacers from the V-Mach kit and the most it can muster is about 10.5-11.0 ft/lb ME. Before the short stroke it made 14.5 ft/lb with everything in and about 11.5 ft/lb with just 2 washer at the top hat.

Not got a clue what it could be...the piston seal was sized after fitting the extension and felt spot on.

The trouble is the ME above is from trying Accupells and JSBs through it but I actually use FAPs so they take it down quite a bit more.

Any suggestions gents?

Cheers,

Darren

[tinbum]

Update... I have to say not any noticeable difference in the cycle or recoil department.

What is different though is that I’ve lost power. I’ve now added all the washers/spacers from the V-Mach kit and the most it can muster is about 10.5-11.0 ft/lb ME. Before the short stroke it made 14.5 ft/lb with everything in and about 11.5 ft/lb with just 2 washer at the top hat.

Not got a clue what it could be...the piston seal was sized after fitting the extension and felt spot on.

The trouble is the ME above is from trying Accupells and JSBs through it but I actually use FAPs so they take it down quite a bit more.

Any suggestions gents?

Cheers,

Darren

I have a used but good genuine seal I could send you to try?

[TonyL]

Update... I have to say not any noticeable difference in the cycle or recoil department.

What is different though is that I’ve lost power. I’ve now added all the washers/spacers from the V-Mach kit and the most it can muster is about 10.5-11.0 ft/lb ME. Before the short stroke it made 14.5 ft/lb with everything in and about 11.5 ft/lb with just 2 washer at the top hat.

Not got a clue what it could be...the piston seal was sized after fitting the extension and felt spot on.

The trouble is the ME above is from trying Accupells and JSBs through it but I actually use FAPs so they take it down quite a bit more.

Any suggestions gents?

Cheers,

Darren

How much preload are you running with all the spacers in?

Standard spring?

New piston seal that you have sized or the one that was previously fitted?

And 11ft.lbs isn't exactly shabby. The difference in muzzle velocity giving 11.4 (as much as many would aim for) will be very little. If it were to be that the firing cycle was nicer, hold sensitivity was reduced and accuracy seemingly improved, I'd prefer a sweet shooting 10.5-11 over a harsher high-11 any day of the week.

[dtdukok]

It’s all V-Mach - spring, seal, sleeve, washers & spacer.

Adding all the gubbins back in has added about 3/4” preload where previously there was almost none.

I’m sure it would shoot nicer if I could get 11 ft/lb (ish) with out the preload.

I thought that was a feature of the V-Mach kit because it made plenty of power before with just the spring on its own.

It seems like I’m having to negate any benefit of the short stroke to get the power up again.

[TonyL]

Steve will have specced the spring assuming standard stroke.

Reduce the swept volume and that smaller volume will have to work harder (all other things being equal).

Maybe this particular rifle may benefit from a longer, softer spring if you wanted to retain the short stroke?

Some would see having to up the preload as being desirable, as it would quicken the piston time even further than already achieved by the short stroke. So much depends on what type of firing cycle you prefer and we're all different.

How does the firing cycle feel to you and have you managed to note any change in observed sight picture disturbance?

[dtdukok]

It’s quick Tony but that’s the V-Mach doing it’s thing. I like the short and sharp cycle and follow through of the pellet is possible depending on target background and if I’m shooting from a rest.

My point is that I didn’t know short stroking was such a power robber, not to this extent.

I don’t fancy losing the V-Mach spring after dropping nearly £100 on the kit a couple of months ago.

I guess I have two choices really...live with it or remove the extension. But then I’m guessing the piston seal would no longer be a good fit after is has been sized with the extension.

[les allam]

It’s quick Tony but that’s the V-Mach doing it’s thing. I like the short and sharp cycle and follow through of the pellet is possible depending on target background and if I’m shooting from a rest.

My point is that I didn’t know short stroking was such a power robber, not to this extent.

I don’t fancy losing the V-Mach spring after dropping nearly £100 on the kit a couple of months ago.

I guess I have two choices really...live with it or remove the extension. But then I’m guessing the piston seal would no longer be a good fit after is has been sized with the extension.

Hi Darren
My 98 set up originally had the stiff short spring, but I had trouble keeping the power down with zero preload.I got Steve to make me a new softer spring with increased length with guides.It was better to shoot with for me , but I still struggled with it. The piston ext in my gun as improved the way it shoots .
I do prefer my guns to have a softer shooting cycle.
Les..