HW90 accuracy problems

[fillythebish 0]

I got my HW90 with a gasram about 3-4 years ago, it shot beautifully and was accurate with accupels up to 60 yards.

 

But then I stopped shooting and my gun was put away for about 1.5 - 2 years, only being used rarely.

 

Now I have started using it again and the zero had dropped by an inch or more, which might suggest the gasram has lost a bit of pressure.

 

Over the past few weeks I have noticed that the zero does not stay the same, and on 2 occasions it has shifted 1 inch low and also a bit too high in the middle of plinking sessions. It hasn't moved to the left or right, just up and down, almost as if the pressure in the gasram is not stable.

 

The scope hasn't moved a bit, as I have a marker for the clamps and the scope, its solid.

 

So I'm wondering what could I do to troubleshoot it?

 

I'm going to get a Chronograph this week and some more pellets to check if the pressure has changed or is unstable.

 

Could it be the barrel?

 

Could it be the crosshairs in the scope?

 

Could it be the gasram?

 

Also how much do gun dealers charge for looking at air rifles?

[SEAN3513 7]

i think chrono is the thing to do....................but could be x hairs.

 

charges vary from dealer to dealer.............have you another scope you can try on it??

 

hope you get sorted mate..........keep us posted

 

all the best

 

sean

[fillythebish 0]

Thanks, I dont have another scope though. I was thinking of taking the silencer off and trying the iron sights on again, but I was never that accurate with those anyway, so i dunno how much they would help.

[Ratman2 2]

Check out the rotary bi-supial valve and the clack over, both may just need a good clean, should get your sub 12 ft/lb gun shooting at 60 yds again.

[fillythebish 0]

Check out the rotary bi-supial valve and the clack over, both may just need a good clean, should get your sub 12 ft/lb gun shooting at 60 yds again.

What are the rotary bi-supial valve and clack over? And how do I clean them?

[jayhunter 0]

Have you considered the internals of the gun may have dried up with such a long period of disuse, a service may be in order, i know they state a gasram requires no maintainance but the rest of the gun does, ( its's still a springer at base level) and rubber seals and such deteriorate over time especially during long periods of disuse when they can simply dry out or worse rust.

[yorkshirelad 0]

defo give the old chrono a shot mate i had the same problem with my old bsa

[fillythebish 0]

defo give the old chrono a shot mate i had the same problem with my old bsa

What was the solution in the end?

[yorkshirelad 0]

i had a problem with the gas ram in her i popped it to my local gun smith and he got her back up to scratch(i had to buy a new gas ram and pay for the fitting) i soon got rid after that,,,i updated to a pcp and touch wood i aint had any prods since then

[Holdaway 2]

Take off the silencer and fire a few shots through it. See if this makes the slightest difference. A friends gun bsa lightning I think, didn't shoot straight until the silencer was off, he had fitted it and made a hash, sent the pellets off left and right but not up and down. Could be a related problem and worth investigating before spending money.

 

Good luck.

 

H

[fillythebish 0]

I had the silencer on shortly after I got the gun, and it fired fine then.

[Coney 3]

Although I admit I am not familar with the HW90 I owned a HW80 that started suffering from nearly the same problem, over a relatively short period shots seemed falling slightly below the point I was aiming at. I tried all sorts swapped the scopes over, changed the silencer and even the washers on the shuttle all to no avail. Eventually I gave up and took it to a gunsmith who later phoned me and told me the rifle was suffering from "barrel droop", basically where the barrel is machined into the breech block there is a port that takes your pellet around this port there was a fibre washer that made the seal between the breech block and the reciever tube. This washer and the one located within the reciever tube ( where the air is pushed out ) were both perished and did not make that air tight seal required for optimum efficiency, this is also considered to cause the barrel to "droop" although it was not noticable at the time. Anyway he changed them both and tightened up the screw that holds the barrel onto the reciever tube and after that she was as good as new. Not saying this is the problem but if this is applicable to your gun have a look and it might just be the problem.

 

Good luck

Coney.

[fillythebish 0]

Yeah I have decided to contact a gun dealer tomorrow and gonna ask him about it and maybe pop it over for him to take a look, if he's able to do that sort of thing.

 

I dont think its even worth me trying to figure it out for myself, or I'll end up doing more harm than good.

 

Thanks for all your help chaps.

 

Typical this is my favourite time of year to shoot, and I was about to book into an airgun holiday house for a week with a rough shoot

Edited May 8, 2008 by fillythebish