Air Arms Owners Club

The FT an HFT season down here has come to and end for the year, so I am just doing some upgrading of scopes and making some changes in preparation for the start of a new season next year, so I thought I'd do a quick check over the chrono and see what the gun is doing.

And to my surprise it was down at 9.5 ft lbs when filled to 170 bar!!!!

The gun is not much over a year old and it was actually 12.05 ft lbs!!! when it was brand new, so I just took off all the AT right away and sorted it myself (down to 11.4ft lbs) rather than xxxx around sending it back to AA , as I wanted to give the hammer rail a polish and fettle it how I like it anyway, and to hell with the warranty, as I always service my rifles myself.

I have a feeling that it may have been fairly warm weather when I set the gun up and it was also still fairly new so what do you think could be the cause of the drop in power?

Could the difference in temperature really make that much of a difference?

Or would it be down to the valve and hammer springs and the valve stem being a little more run in?

I have just bought a full seal kit and a new valve stem and hammer Spring and valve Spring from Julian , so I'm just gonna strip it and give it a full service and replace those parts which will sort the problem but was just wandering what you guys think will have caused the significant drop in power??

If I now set this rifle up this time of year to around 11.4ft lbs will it end up being well over power in the summer when it's warmer?

I know that temperature does make a difference but I didn't think it would alter it that much!

On a hot summer day both my S400 and S200,s power goes up. Can't remember by how much but I think it's definitely a 1/2 ftlb or so.

That's why I'm asking really, a drop of 1/2 a ft lb wouldn't be an issue but I'm looking at a drop of 2 full ft lbs.

I will replace the parts and seals and leave the Venturi screw where it is and see what difference it makes.

it could be the breech seal . check that (FP121 or S536 depending on the age of your MPR).

Thanks Julian, will have a look at that, it's not long over a year old so I assume the breach seal I need will be in the service kit you have sent me?

Also, I have not had the barrel out of this gun before , is it likely to be a pain in the Axx to get out? Loctite Ect

Stoohundred wrote:Thanks Julian, will have a look at that, it's not long over a year old so I assume the breach seal I need will be in the service kit you have sent me?

Also, I have not had the barrel out of this gun before , is it likely to be a pain in the Axx to get out? Loctite Ect

both seals should be in the kit .

if the barrel doesn't come out easily just replace the seal in situ , its fiddly but not impossible .

Thanks Julian, managed to get the barrel off with a little heat from the hair drier, still bleddy fiddly to change tho, even with the barrel off.

All back together now and back to normal. Cheers.

Stoohundred wrote:Thanks Julian, managed to get the barrel off with a little heat from the hair drier, still bleddy fiddly to change tho, even with the barrel off.

All back together now and back to normal. Cheers.

good news .