simple answer....buy or lend a chrono.
if your hw35 is a .22 then theres a good chance it will be doing at least 10ft.lbs.
also bear in mind the hw35 weighs more so it will absorb more recoil that the mercury.
After many attempts tuning my 30 year old leather piston washered HW35 using the excellent advice contained on this forum, I have happily been running it for the umpteenth time - the latest reason being the replacement of a snapped mainspring.
This item was one supplied in a tuning kit in the 80's along with Cardew's tuning book yet being honest the gun has never lived up to expectations. The new spring is a standard secondhand Weihrauch item kindly donated by Airgun God. In addition I have now radiused/deburred the transfer port and fitted a plastic sleeve to the inside of the piston together with Delrin Top Hat and Guides supplied by chambers.
The rifle is shooting very sweetly: The horrific twang and erratic grouping have been replaced with a very good grouping but it seems the rifle is well down on power despite having around 2-300 pellets through it since the last rebuild and approximately 1600 shots since the Piston/cylinder/washer etc were tuned.
The leather piston washer was sized so that the piston just falls under its own weight unless the transfer port is blocked.
I don't have a chronograph and the power has only been compared to a 30 year old Mercury also in .22. The comparison is very unscientific: Using a variety of pellets at 10 metres into a steel pellet catcher, the pellets from the Mercury are always significantly more flattened than those from the HW35.
The Mercury is completely untouched and I am forced to conclude that the HW35 is producing a lot less than 10ftlbs.
Where do I go from here please?
simple answer....buy or lend a chrono.
if your hw35 is a .22 then theres a good chance it will be doing at least 10ft.lbs.
also bear in mind the hw35 weighs more so it will absorb more recoil that the mercury.
Hi,
You might find this interesting:
http://www.airgunbbs.com/forums/show...t=mystery+HW35
My own '35 suffers from this.
Regards,
Andy.
Thank you both for your comments.
Andy W
I don't think I have this problem since before the latest rebuild the rifle was producing a lot more power albeit with the accuracy of a shotgun and the cylinder has not been touched since then.
Ikarma 70
Your point regarding the chrono is of course valid and I am trying to borrow one locally.
I am fairly certain however that given the poorer pellet deformation from the HW35 in comparison to the Mercury (which I believe only produce around 10ftlb's or so), that the HW35 must be producing less. I suppose the alternative is of course that I have an exceptional Mercury...
Last edited by copperjacket; 17-03-2008 at 02:02 PM.
Hi Copper Jacket
Do not under estimate your Mercury, they are more than capable of spitting pellets out at 11 + ft/lbs with very little work on them
Can not help with the HW35 though as never owned one, nice bit of kit though. Can you not get a local airgun dealer to run the 35 over a chrono just to put some context into the perceived lack of power.
ATB Keith
Last edited by mxgb; 17-03-2008 at 02:21 PM. Reason: correct typing fudge
mark combro for £39 will sort you out, nice and reliable bit of kit. the old leather washer was very forgiving being organic in material especially with an out of shape cylinder...there is a very fine line between good power and lack of consistency...i cut my teeth on a 35....wish i had a £ for everytime i opened it up and cleaned it...
Rapid 7 / 10-22 ATN 2 Stiller Predator .204 Pulsar N970 Tikka T3 semi custom ATN MARS thermal.204 Tikka T3 Semi.223 Wylde IOR Operator Lawton 6mmBR Kahles Gen 3 - Stiller 6.5 x 47 Bushnell BDX - Winchester Red Performance SX3 12g
buy a piston head convertor from john knibbs then fit a nylon piston head.even send it off to steve pope have it sized to fit your cyilinder if its worn.ive just finished my 35 luxus its running at 11.5 but smooth i only aded two steel washers to the piston and one to the spring guide. cut a hw 80 spring down to 29 coils the hw35 is 28 the extra coil seems to work.hope this helps .