tx200 mk 2 - Hot

[juanpablo]

As promised here is the report after fitting the new piston seal today.
To recap the gun has had new breech seals, piston seal, spring and front guide all in an attempt to tame the harsh recoil which has "crept up on me" over 18 years of ownership but not much use, and also chasing a reduction of 1ft/lb.
New piston seal was very tight, as in difficult to get into the compression tube, so I touched it with wet and dry, taking care not to alter the profile and, from what I can make out from the net was still tight at final fit.
No spacers were fitted.
What a difference! so much nicer and easier to shoot and the Combro is giving me readings that, at the moment, are a lot less scary.
The readings were taken after 100 pellets (left to cool off after 4 then 6 etc during running in) but the consistency is not yet great and I was surprised to see that Hobbys produced the same power as LRG and Accupell with Superdomes down by half a ft/lb (my Hw95 loves them)
I know that I need to keep my eye on this as she beds in.

Thanks to all who have given time to share their knowledge.

Dave

[rogers1]

Hi guys (JuanPablo)

I have just followed this thread right through and can only say that you have done all the things I did with my TX in the years following me buying it new in mid 2006. It's a MKIII in .177

Mine went 'hot' four times in total. The first three I was able to remove washers to achieve a (temporary) solution.

It just kept creeping up there...

The last time, I had no preload, so I machined a bit off the top hat.

That left it just under the magic dozen with my lightweight pellets (Defiants @ 7.5 grains) , and every other pellet I tried reduced the MV/energy. Result.

I should explain that this gun is on its original spring which has 36K shots through it, all is good so far.

I have since then short stroked this gun, which was achieved by fitting an ISP extended latch rod.
The ABT still functions (albeit only with one click!)

Muzzle energy is 11.1fpe give or take.

The result of fitting the latch rod ?

Well, the gun is no more accurate or consistent than it was in long stroke mode, but by the cringe, its previous hold sensitivity is no longer there. (It's the air rifle equivalent of Sensodyne toothpaste)
I can now rest the gun on anything and it hits what it's pointed at, no POI shifts no matter how I hold it. My best (target) results have occurred since shortening the stroke and one cold morning, in the woods on one of my perms, I set out a piece of corrugated card and stuck some ShootN-C 20mm dots to it. I gradually moved the card further back, laid alongside my trusty 100m builders tape. At 73 metres, I put ten rounds through a dot, resting the gun on a cushion on a pile of logs.

Hope you get on OK with yours. They are superb guns and worth the effort.

Duncan

[juanpablo]

Hi Duncan and thanks for that.
Well, after a total of 300 rounds she is showing mid to high 11s so today the top hat is away to a friends engineering shop to have the thickness of a AA washer removed, I wonder if you would be good enough to share your view on the result.
Assuming I fit a washer the length will remain the same but obviously the weight of the moving assembly is less.
I cannot decide what effect this will have on power as it will accelerate faster but not carry the same energy but at least I have the option of removing the washer although there is very little preload as it stands and, after the mod to the top hat I expect almost zero.

I am also not completely happy about the security of fit of the top hat to spring - should I use Loctite?
Agree that they are super guns but I have to say that I don't find them hold sensitive although that's me comparing it to my previous 1974 Airsporter!
Your results are just superb, well done on the modifications, and the hours of practice required to make use of them.

Dave