Seeing as I'm hosting the AirArms Owners Club charity meeting next month I thought it would be a good idea if I bought an AirArms gun to use over the weekend.

So I bought a cheap MK2 TX200 in .22" flavour off our very own Edbear for the princely sum of £125, so giving me something to tune and play with.

Now here's the twist, rather than me just lathing loads of new parts up I've decided to see what could be acheived using easily available off the shelf parts at minimum cost --- This should allow anyone who can strip a TX to replicate what I'm up to.

Now even though the MK 2 TX has a relatively short stroke I thought I'd shorten it a little bit more and I'm told that the HW77 piston seal is more efficient than the AirArms seal --- so I bought a piston allowing for both. :-


http://s1138.photobucket.com/user/mi...tml?sort=3&o=4


Now the LGV seal has a central tit that would restrict flow on a TX with it's central port so I dug a 25mm Weihrauch seal out the spares box. :-


http://s1138.photobucket.com/user/mi...tml?sort=3&o=6


And this picture shows the difference in piston lengths (LGV on right) :-


http://s1138.photobucket.com/user/mi...tml?sort=3&o=5


The difference in piston lengths with the Weihrauch seal fitted measured at 7.8mm, so with the original TX MK2 stroke being 84mm, fitting the LGV piston should drop the stroke down to 76.2mm.


Well I had a little bit of time this afternoon so I threw my TX together (bone dry) and ran a quick chrono string to see where I was going.

Results :-

Hobbies 645 ft/s = 10.99 ftlbs

Superdomes 604 ft/s = 11.75 ftlbs

Jumbos 550 ft/s = 10.75 ftlbs


The above results are just from changing the piston and removing 4mm of preload from the spring.

If I get a little bit of time in the week I have a few other little tweaks I'd like to try involving shedding a little weight from the piston by way of removing the 6 gram steel top hat and turning the spring round as I have three collapsed coils on the front of the spring which I calculate to add 11 grams to the overall piston weight.


So there you are this is my starting point and I'll play around to lower the power a bit more and to see if I can make the gun sweeter, though in all honesty it feels really nice how it's running now.




All the best Mick