TX200 top hat options

[mrgeoff]

Just picked up a lovely mk2 TX200 in LH drive. 177
So after pulling out 5mm of washers, it’s down to just the 1 thin washer and still a bit close to the wind, so need to look elsewhere.

2 things I have noticed, 1 the top hat is quite long, and 2, just about every thread says replace the steel top hat with a plastic one on a 177. (Either of which I could make shorter)

So why do I need less mass if AA have designed it that way? The FAC version has a different top hat so it’s not that.

I’m specificly interested in the combined piston mass, as designed vs the tuners.
Who has the optimum solution to mass vs spring etc.


Thanks!

[JMH123]

A more simple response than you were looking for, but remove that last washer. I recently removed only the slip washer from the bottom of the spring guide and it took 3 1/2 ftlbs off a .22 TX. Surprisingly sensitive......

[jayboy]

Take a coil off the spring?
Surely removing the piston weight and putting a lower profile Delrin version will take away a fair bit of preload, however, the spring will extend quicker as the weight slows the spring, making the cycle slightly slower. I think.

[mrgeoff]

I am more looking for info around replacing the steel top hat with delrin, more the technical reason, and more so if something else needs to be done to compliment the lower mass?


Thanks!

[FPoole]

Replacing the steel tophat with a plastic one will usually help the firing cycle and should lower the power a bit. I don't know why, but it does seem better.

[Shed tuner]

the piston is just too heavy for the stroke/swept volume, for a transfer port of that size.

on the 77 they coppied, the trans post is 3.0 x 6mm. the TX is 3.8x10mm. That's well over doubel the tp volume, so less pressure build up / less bounce, so a heavier piston is the last thing you need. Remember, this was back in the day when everyone thoguht heavier pistons = better...

clearly there is a sweet spot, but a heavier piston takes more force to accelerate to the same speed; on the plus size it resists bounce better.
A light piston accelerates up to speed much faster, but is more prone to bounce earlier.

The MK2 with 230gram piston plus around 20g is just too heavy for it's stroke / TP volume combination. 200g is about perfect - some prefer a little lighter, some a little heavier, but 230 is absolutely at the top end on it's own, without the steel TH.

sleave down the TP when you are in there too.. it'll raise power a fraction and shoot softer. 3.2mm should be nice if it's still full length...