Inconsistent TXHC

[prosport.177]

You should get hold of Tony as looks like one of his comp tubes.. this is not a standard tx comp tube..

[Muskett]

I know it might seem obvious but have you tried checking all the basics. Bedding screws, the scope mounts, and switching the scope to a know good one?

I just say this because sometimes it is something else. As I told a frustrated friend: "you can't zero a rifle if the reticule is broken". His reply: "is it? Oh yes, deeerrrr." And that was £100 of ammo down range for nothing.

[Hellequin]

You should get hold of Tony as looks like one of his comp tubes.. this is not a standard tx comp tube..

I've messaged him today mate. Having now got the rifle apart, there's a few things I've questions about but may well be completely normal, so I'll await an answer from him.

I know it might seem obvious but have you tried checking all the basics. Bedding screws, the scope mounts, and switching the scope to a know good one?

I just say this because sometimes it is something else. As I told a frustrated friend: "you can't zero a rifle if the reticule is broken". His reply: "is it? Oh yes, deeerrrr." And that was £100 of ammo down range for nothing.

Yes mate, all that has been checked. I think I've found the culprit in that o-ring.

[NickG]

An update to this...

I've stripped the TX this morning. I've found two possible issues:

1. There was only one o-ring breech seal- isn't there supposed to be two fitted?

2. There's another o-ring which sits in a recess in front of the breech seals. It's wider so doesn't look the same. It looks chewed up/split.

I've added a link with images, arrow pointing to the chewed o-ring. Any advice appreciated.


https://ibb.co/album/5YbCFm

That looks like belt and braces approach, the thicker o ring in the bottom ( around the transfer port) will be doing the sealing , the damaged one that works on the outside diameter of the barrel, is redundant, if the other is working, it's a back up at best.
Probably not the root of your problems.

[Hellequin]

That looks like belt and braces approach, the thicker o ring in the bottom ( around the transfer port) will be doing the sealing , the damaged one that works on the outside diameter of the barrel, is redundant, if the other is working, it's a back up at best.
Probably not the root of your problems.

To be fair, that's what Tony said, albeit with less detail!

I'm going to replace them both anyway, but the rest looks to be all fine- no issues with spring, guide, top hat or piston & seal. It did seem to be over lubed, with some on the face of the piston seal which was a surprise.

I've done a proper degrease so once I have the correct 'secondary' o-ring I'll reassemble with minimal lube and try again. He also suggested trying different pellets so I'll be buying some QYS to try along with the JSB Express that I already have.

[Muskett]

Keep us posted at how it goes. I love it when a rifle gets back to tac driving.

[Hellequin]

Keep us posted at how it goes. I love it when a rifle gets back to tac driving.

Will do, thanks. I'm hopeful it'll be sorted soon, but can't reassemble until next weekend as I've a week away in the truck from tomorrow. At least the new o-rings will be waiting for me when I'm back.

[Hellequin]

A quick (ish) update on this thread and my TXHC.

I fitted a new breech seal and the larger o-ring seal which fits (kind of) inside a recess in front of the breech seal. Strangely (to my mind at least) this recess is not the same internal diameter all the way around. Imagine the recess with a very small protruding section on one part, which is probably about 2mm wide. This protrusion doesn't allow the o-ring to sit completely flush INSIDE the recess. I think it's possibly why the previous o-ring was knackered as it was getting caught.
I've no idea why it's there or what it does.

Anyway...

The rifle was reassembled today with the new seals. It had had a proper clean & degrease followed by minimal lubing prior to reassembly.

I put about 30 JSB Exact Express through before doing a chrono test with two 10 shot strings, which were pretty similar but the 2nd was best, as I expected.

It's now hovering around 11ft/lb power wise, with a high of 772fps & low of 665fps.
*EDIT- should read high of 772 & low of 765

I'm happy with that to be honest but still don't really know why it was so inconsistent before, given both Tony Leach who did the work & Nick G here suggested it was unlikely to be the seal at fault.

Either way, I'm now happy that the rifle is shooting as I expected it to.

Springers are brilliant, but baffling. Like voodoo magic...

[tinbum]

It's now hovering around 11ft/lb power wise, with a high of 772fps & low of 665fps.

I'm happy with that

I’m guessing that is a typo?

[Hellequin]

I’m guessing that is a typo?

Oops! Yep, 772-765

[TonyL]

Glad you've now sorted it.