Weihrauch HW100 T has become completely inaccurate

[jepho]

I guess we don't know the full story, but it is a bit of a concern that Hull Cartridge couldn't sort it, whether or not it was an official import. Makes you wonder if they could sort a HC import with the same fault.

Putting a nice face on it, they possibly could not find the issue. My gunsmith is a guy with 30 years experience and highly regarded and he could not sort it. I thought it was nice of them to try. My hope is that Weihrauch will have a better idea about this type of failure because they may have seen it before. If not, they should try to fix it so that they can inform their distributors.

From an engineering viewpoint, I wondered if the linkage from the cocking arm has become inaccurate in some subtle manner. For example, something along the lines of the holes that hold the hinge pins of the cocking handle to the linkage that moves the probe, becoming out of round.

[tmstech]

Having not read all the posts on this long thread, I wonder how many rounds this rifle has fired? I would imagine that eventually all mechanical items will wear out just from normal but high usage? What's the lifetime of a pcp airgun?

[jepho]

Having not read all the posts on this long thread, I wonder how many rounds this rifle has fired? I would imagine that eventually all mechanical items will wear out just from normal but high usage? What's the lifetime of a pcp airgun?

Better than 18 months one would hope. About 8,000 pellets put through the rifle in 18 months

[krisko]

I had a look on my hw100 and I can tell you there is a spring loaded ball bearing that is what indexes the magazine, not only the rotating mechanism...just look at the magazine it has holes on it.

You can replace the indexing arm or tweak the metal block maybe you can put a shim under it to lift it higher or file off the indexing arm tip....

The metal block I am talking about is what is on the bottom of the hammer, I dont remember if it is overrotating or underrotating, are you sure it is really magazine alignement related or random poor precision only?

Is you hammer aligned hitting the valve stem without hitting the edge of the valve block? The hammer can have also signes of wear on one side if there is some alignement issue. Would need to inspect visually, everything can be fixed only if the action is wasted that’s would be it.

Can you see the aluminium, wear on the action, in the area where the pellet probe is riding on the vertical rollers/pins. The groove is on the ‘ceiling’. In that chamber where the bumper or ing is and cocking linkage etc.

[tmstech]

Better than 18 months one would hope. About 8,000 pellets put through the rifle in 18 months

Can't be that then. Next.

[jepho]

It looks as if I may have an answer. I retrieved my gun today and had an examination of the gun visually and just slowly worked the cocking lever.

When the cocking lever is taken through its range of movement (that is just letting it spring open only) and then the cocking lever is closed... everything appears to be normal and the lever moves smoothly through its whole range.

When the lever is used to actually cock the weapon, as it is moved forward to a position just before it is fully closed, the lever snags very slightly on a sprung button. Very slow motion action shows that the snagging causes the probe to move and raise very slightly.

The sprung button is the hammer securing bolt. A hammer bolt plate and hammer securing bolt spring are a part of the assembly along with a couple of hammer bolt plate screws.

The part numbers are 2633, 2634, 2635 and 2636 from John Knibbs's catalogue.

http://www.airgunspares.com/store/ca...100/page3.html


a link to all of the parts on the same page within the first couple of lines.

http://www.airgunspares.com/store/pr...Part-No.-2636/


This is the hammer securing bolt ringed in red.

https://www.dropbox.com/s/o6kp6y6kva...0bolt.jpg?dl=0

This shows the cocking lever linkage riding up over the hammer securing bolt.

https://www.dropbox.com/s/60ebto5509...0bolt.jpg?dl=0

[krisko]

That’s by design, some evil genius put it in there.

You can remove that, it is a redundant part in my opinion. supposed to prevent accidental discharge while you are working the lever, I think it has a slot through it the hammers side glides in it. I have mine in a bag never reinstalled it. Never had any misfires. Anyway pull it out and retest. Worst case it won’t make any differerence and then you just reinstall it back. The hammer may have to come out to get it out there can’t remember, maybe just the covering plate, there is a spring under the plate too.
It is possible that you have to drive the main cocking lever pin out from inside out, it is the one what’s top you see on the rear of the scope rail. it is a pain to do it, some bad quality YouTube videos suggest a coat hanger for the trick... anyway you have nothing to lose so just rep apart the whole thing you will see a lot more to visually inspect, good luck

P.s. it may have still nothing to do with your main problem, but it is a method of elimination, isn’t it

[Chalkie]

I am from the other side AGF, been dipping in and out following this. l have joined the forum to offer my take. I have not read all the thread so apologies if someone has already covered this
I purchase a HW100 KT about 3 years ago and l was never happy with its grouping. I tried all the the things other members have mentioned, as a last resort l purchased a new barrel vowing if that didn't work l'd take up crown green bowls.
Well it didn't work
Try this...load a felt, remove the moderator and spray WD40 down the muzzle end. The felt will stop the WD entering the internals. Fire the gun
Place about 100 pellets in a tin add a few drops of light oil. Anything will do for now. Try the grouping
Worked for me, my take is that a PCP needs lube in the barrel, pellets alone do not provide sufficient lube
If it works or improves then try different lubes until you find one that groups the best
Mine 20 mm spinners 50 yds 8/10 times. Simple but it worked for me. Best performing pellet JSB Heavy