TX200 - Mk2 piston into a Mk3?

[FPoole]

Note that the MarkII weight/top hat doesn't fit into the end of the spring, like the MarkIII, it's just a thick weight and looks very much like it's not in the piston. As noted above, you should have about 110 mm depth, inside, from piston skirt to the front end where the top hat sits.

[cooper_dan]

Note that the MarkII weight/top hat doesn't fit into the end of the spring, like the MarkIII, it's just a thick weight and looks very much like it's not in the piston. As noted above, you should have about 110 mm depth, inside, from piston skirt to the front end where the top hat sits.

Actually it does. It looks like a mk3 version but the thinner section has a very coarse thread on it. This screws into the 3 collapsed coils. I think you are thinking of the additional washer (9mm thick I think) which may or may not have been used from the factory, depending on the power

[FPoole]

Actually it does. It looks like a mk3 version but the thinner section has a very coarse thread on it. This screws into the 3 collapsed coils. I think you are thinking of the additional washer (9mm thick I think) which may or may not have been used from the factory, depending on the power

Yes, I was a bit un-clear and was talking of the weight only. The top hat will always pull out with the spring on a MarkI/II. That 9mm weight looks just like the bottom of the piston and is easy to miss. Don't ask how I know, but I had a .177 MarkI shooting 8.64 H&N's at 850 fps, until I figured out the weight was still in there.

[prosport.177]

Yep and more often than not I have found metal, brass turned up washers hiding under the top hat. These are the result of previous owners upping pre load, or upping power.. These can get stuck.. Only way to know is to measure spring room inside the piston..
The last time I had one of these I had to remove latch rod from piston to find a half inch lathe turned washer in front.

[NickG]

Yep and more often than not I have found metal, brass turned up washers hiding under the top hat. These are the result of previous owners upping pre load, or upping power.. These can get stuck.. Only way to know is to measure spring room inside the piston..
The last time I had one of these I had to remove latch rod from piston to find a half inch lathe turned washer in front.

Nice what some people get up to in the name of tuning !, loctite can be the enemy here , if its not cleaned off properly after fitting the latch rod the piston weight gets glued in as well .

[prosport.177]

Ha ha Nick ,)
She'd tuners,!phhhft what do they know

[Weasle]

Nice what some people get up to in the name of tuning !, loctite can be the enemy here , if its not cleaned off properly after fitting the latch rod the piston weight gets glued in as well .

I'm certain that there is nothing hiding in the piston void, as its brand new......

Cheers

Steve

[Shed tuner]

Ha ha Nick ,)
She'd tuners,!phhhft what do they know

Oi

[prosport.177]

Oi

He he 😂

[prosport.177]

Didn't know there were any new mk1-2 pistons left?

Is it a piston some One has put a rod in? What shape is the latch rod? As the early short stroke piston had a slightly different profile latch rod compared to the mk3 rod..

[Weasle]

Didn't know there were any new mk1-2 pistons left?

Is it a piston some One has put a rod in? What shape is the latch rod? As the early short stroke piston had a slightly different profile latch rod compared to the mk3 rod..

Mr Knibbs......

[NickG]

Many thanks to you all.

I will check out the latch rod profile....

I will also source a Mk 2 spring from elsewhere and start again - I already have a Mk2 top hat and spring guide soused from the nice Mr Bum.

I've built the Mk2 piston using one of Mr Popes seals...which have worked for me on all of my other AA Tx/ProSport derivatives.

Cheers

Steve

If you have after market guides put the top hat and guide on the piston rod without the spring then push it into your trigger block to make sure it latches , chances are your guide is too long.

[Weasle]

If you have after market guides put the top hat and guide on the piston rod without the spring then push it into your trigger block to make sure it latches , chances are your guide is too long.

Many thanks.

I have unfortunately already tried.......

Cheers

Steve

[NickG]

Many thanks.

I have unfortunately already tried.......

Cheers

Steve

does the trigger latch outside of the gun when tried as i suggested ?

[Shed tuner]

if it's not the length of the guides it may well be the centralisation of the rod in the piston - is it centred correctly ? Also is the rear guide "brim" OD the full size of the main tube of the gun, thereby preventing it from moving off centre ? Also look at the trigger block - does the lead into the hole in the trigger block through which the piston rod passes show any signs of being hit / metal contact ?