Question on the HW75 and clamping it down

[rizaloo]

Hey guys.  So I picked up a HW75 used from a guy on the canadian gun forums as I just couldn't pass up an opportunity to try it out.

It's super accurate, as expected!  But there's a little issue, or perhaps it's not an issue and it's just the design. 

So when I close the gun up to finish cocking it, the top doesn't completely go down.  Most of the time I have to give it another good squeeze for it to completely close.  I have the HW45 and it doesn't have this issue.

For owners of the HW75 - do you experience this?

[Technical Ted]

Mine closes on the cocking stroke just fine. 


Ted

[Brazos]

Not 100% sure what you mean.  It is a SSP so you kind of fight it to the end.  I did find with mine that (this is hard to describe so bear with me) silver, round, disc came loose.  This part is located at the end of the end of the blued tube that houses the piston.  The silver "hydraulic" type rod pushes thru the hole in the silver disc at the end of the piston housing.  This disc would pop out and slide up and down the "push rod".  I noticed there was a set screw on the bottom to hold the disc in.  This happened several times and I eventually put locktite on the set screw and it solved the problem.  I am not sure if this is related to your issue but if the silver disc was loose and having a hard time sliding back into the blued piston housing it could explain it.  If you bought the gun used and it came to you this way you may not know any better if the silver disc is sliding up and down the piston rod when you go to cock it.  I hope all this made sense.  If not PM me with your phone number and I will call you and go over on the phone.  My 75 started doing this right away, though an easy issue to resolve, I am sure most others do the same.

[rizaloo]

I appreciate the offer and the information, I may take you up on that!

As for the SSP, I do indeed fight it till the end, but even then, the top isn't fully closed.  It closes with a snap too, as you'd expect.  I briefly used the HW40 and it snapped shut properly every single stroke.

I'll take some photos of it - it's quite apparent that there's a small gap and the top isn't firmly closed up after cocking it.  Maybe even a quick video.

I'm really hoping it's a simple fix because this gun was a second hand purchase from someone with a great reputation, so I can't see him selling it to me like this knowingly.  He had barely used it, bought it new and stored it in a humidity controlled environment (I made it a point to ask questions) so I thought I was golden.  I mean, it's always possible it got jostled good during shipping but the boxes it was in were mint.

I also want to add that I'm not very good at tinkering with these guns, which is why I prefer to get higher quality guns like Weihrauch; don't want any fuss.

[rizaloo]

Here I made an image to show what I mean.  The image on the bottom is how it looks like half of the time after cocking it.  You can see here that it isn't closed all the way - the gap is quite visible.  If I push down again after, it sometimes closes up.  Additionally, when it's shot the top sometimes pops open as if the latch had been pressed or not completely caught in.

I just shot it a few dozen times and it's apparent that every time I have to forcibly clamp it down after the stroke, the aim is off.  No idea why.

I'm pretty bummed about this.  I doubt there's anyone in my vicinity that knows how to repair airguns.

[robertr]

 Maybe you have some debris under the cylinder preventing the catch from closing all the way. Take your barrel off and see if it closes better, if it does then you know at least it is a barrel alignment problem.Maybe the barrel was shimmed out to far? I am going by similar problems I had with my P-17, might apply, might not.

[Beerbladder]

Can you take some pictures with the pistol open. This pistol is pretty simple to work on.
Schematic: https://www.pyramydair.com/air-gunsairsoft-schematics
Open up the gun and look underneath the piston cylinder for a pellet, also look around the barrel area. I have dropped pellets and had them get stuck inside this pistol before.

[rizaloo]

Here are some photos.  Got my wife to hold it at certain angles.  I can't see any issues.  To check under the piston for a pellet, I have to take it apart, correct?  Is that what you mean?

Also, the barrel seems to be at the right spot and does not move if I try to slide it forward/backward.  I can always remove it and try closing the gun as suggested and see if its alignment is part of the issue.

If I have to get a gunsmith to look at it - I need any recommendations for Canadian gunsmiths.  Not sure how much of a Canadian presence there is on here, though.

[robertr]

Easy as borscht to take that thing apart , two screws to remove and barrel lifts out. Here is a pic if you decide to tackle it yourself.
https://www.gunspares.co.uk/products/24570/HW75/

[Beerbladder]

No need to mess with the barrel, just make sure no pellets are jammed up in there.
 You also need to look under the piston cylinder. There is a tiny metric grub screw that holds the piston rod in place (front of the piston rod), and the rear (near the hammer) section pivots on a pin held in place with a E-clip. Remove those two pins, and the whole piston assembly lifts out.

[robertr]

No need to mess with the barrel, just make sure no pellets are jammed up in there.

What would your procedure be for checking if it is shimmed or not, is there another way without removing the barrel? I know when I shimmed my P-17 barrel to much it did exactly as the OP described. Might not be the problem but must be eliminated as the cause of the problem.JMO