Inconsistent TXHC

[Hellequin]

I've a TX200HC in .177 cal which has been tuned and given the 22mm skirtless piston treatment, running (I'm told) around 84mm stroke.

The rifle is lovely but slightly low on power and very inconsistent. Last chrono string (30 shots) started with a 10.9/763fps then an 11/768fps but afterwards dropped- 10.7ft/lb down to 10.2, then into the 9's with a low of 9.5 then back up to around 9.9ft/lb.
High fps was 768 and low was 714. I'd expect better than that from an el cheapo Gamo or Hatsan!

Now, the tuner had told the previous owner it would need running in & then trying with some recommended pellets (JSB) and I've now done this.

My question, before I approach the tuner for his advice, is are there any basics I need to check that might solve it? I'm thinking possibly breech seals?

I'm not too worried about power levels. I'd like a little more, nearer 11ft/lb but it's only used for plinking targets so I'm more interested in consistency. Years ago I had a tuned HW80K running on FAC at near 20ft/lb which was ultra consistent with a spread of just 3 or 4fps over a 30 shot string. Really I'd expect similar from this TX.

Any advice welcome, and yes I know 'contact the tuner' is best bet but I just want to cover any basics before going down the 'your work isn't great' route...

Cheers

[angrybear]

Maybe it just doesn't like the pellets, try others & for the purpose of the test, weigh them so you know they're within 0.1-0.2gn.

If it's still all over the place, speak to the tuner but don't go in saying his work is no good,
just explain that it's inconsistent & ask for it to be checked over in case something's failed inside.

[Hellequin]

Maybe it just doesn't like the pellets, try others & for the purpose of the test, weigh them so you know they're within 0.1-0.2gn.

If it's still all over the place, speak to the tuner but don't go in saying his work is no good,
just explain that it's inconsistent & ask for it to be checked over in case something's failed inside.

I wasn't seriously going to go in with "your work sucks". I'm a blunt Yorkshireman but do have a little diplomacy in me

I have tried different pellets & the results are similar, hence wondering if it might be iffy breech seals.

I'm sure most folk could guess who has done the work and he has a very good reputation, especially with the TX. I just want to make sure I've covered any potential simple fixes before I ask him to take a proper look.

[NickG]

Wouldn't hurt to change the breech seals, they are relatively cheap, however small diameter tunes can be pellet sensitive, however I wouldn't expect inconsistency, just different power with different brand/size , you probably need to talk to the maker.

[Hellequin]

Wouldn't hurt to change the breech seals, they are relatively cheap, however small diameter tunes can be pellet sensitive, however I wouldn't expect inconsistency, just different power with different brand/size , you probably need to talk to the maker.

Thanks Nick. I've ordered some breech seals just to try first as I'd rather not bother him if it's something that simple. If it doesn't do the trick I'll drop him a line.

As I said, I'm not too fussed that the power is a little low, I just want it to be consistent.

[tinbum]

Check for debris ahead of the compression tube, a pellet dropped there can be hammered into a thin veneer that can reduce it’s ability to seal.

Failing that, try contacting the tuner. I’m sure he’ll tell you what you are doing wrong.

[prosport.177]

I wasn't seriously going to go in with "your work sucks". I'm a blunt Yorkshireman but do have a little diplomacy in me

I have tried different pellets & the results are similar, hence wondering if it might be iffy breech seals.

I'm sure most folk could guess who has done the work and he has a very good reputation, especially with the TX. I just want to make sure I've covered any potential simple fixes before I ask him to take a proper look.

Get hold of the original tuner who did conversion .. I am sure they will sort out the issue . If it is who we think it is he's over on face ache pages get hold of him... reading some posts over there might shed some light on it for you..
Cheers

[Hellequin]

Get hold of the original tuner who did conversion .. I am sure they will sort out the issue . If it is who we think it is he's over on face ache pages get hold of him... reading some posts over there might shed some light on it for you..
Cheers

Ah good old BookFace... I'll have a look cheers

[Edtwozeronine]

When I recently gave my TX200. 22 back to our clubs gunsmith (needed the safety replacing) he tested it out of due diligence and it's banging out 11.5 ft/lbs with Exacts, a pellet I don't personally use as a plinker.

My point being they can put out the power when they're running right.