257 Texan Valve Lock or Something Else?

[steveoh]

257 Texan Valve Lock or Something Else?

My Texan acted strange the last time I was shooting at Kevin's, and today I shot it once in the backyard and it acted strange again.

1. Texan has about 2k of air in it.
2. Power wheel is about 1/4 power setting.
3. I attach the hose from my big tank to the Texan and fill to 3k as per the Wika Gauge on the tank.
4. I look at the Texan and the gauge has not moved from 2k. What?
5. I load the gun and shoot at my target on the hill that is about 20" thick of shredded rubber in a 2x6 framed all around box.
6. Fill the Texan again, and same thing happens. Tank Gauge registers 3k, but gauge on rifle measures 2k.
7. I scratch my head, and open the breach and go back to the tank to try filling again, only this time the tank gauge is equalized with the rifle gauge. Double What?
8. I open the valve on the tank and fill to 3k, and this time the tank and rifle gauges agree with each other.

Any idea what is going on?  Is this the infamous Texan Valve Lock? or something else, or a combination of things?

And it's Turkey Season, durnit.

[cosmic]

Bad gauge on the rifle.. Get one from Talon Tunes or get a Wika..

[Loren]

Bad gauge on the rifle.. Get one from Talon Tunes or get a Wika..

My thoughts too, a broken/defunct gage on the rifle's tank.

[TPL]

Jamming fill (check-) valve on the gun.

[steveoh]

Jamming fill (check-) valve on the gun.

That’s one of my thoughts too.

I think that it’s most likely more than a gauge.

At Kevin’s during our last shoot, the Texan appeared to be filled to 3k. But initial shots were low power. The sound indicated lower power, and the bullet dropping two feet at
at the target also indicated low power. I had changed nothing on the rifle in between outings other than cleaning the barrel.

I fiddled with the power wheel the last shoot and increased the power way way up and the rifle got back it’s “zing”. Turned it back to the normal setting which did not have the correct power. I ended up one full revolution on the power wheel to get back to  the same point of impact at 100 yards. Then I was able to get reasonably consistent strings at 100 yards, and qualified for NUAH.

I initially suspected the fill nipple valve wasn’t opening. And now I suspect the gauge as well, but I am suspicious that there is more going on.

Will depressurize, swap out the gauge, pull the fill nipple and inspect and clean. Then maybe it’s time to put in a new stock hammer spring.

And yep time to run it by the chrony and not rely on my ears.

[dyotat100]

What is the temperature like compared to how it shot before?

Condors need more hammer spring in the winter cooler months. So I'm sure the Texan is the same

[rsterne]

Doug, can you "set" the stock Condor hammer spring by compressing it to coil bind before installing?.... or will that make it so short you can't reach maximum power?....

Bob

[steveoh]

What is the temperature like compared to how it shot before?

Condors need more hammer spring in the winter cooler months. So I'm sure the Texan is the same

Last shoot was cool in morning, maybe 50 degrees. It warmed up as the sun did it’s thing.

I have seen performance changes going from cold to hot. The Texan and other rifles seem happier warm to hot vs cold.

[dyotat100]

Doug, can you "set" the stock Condor hammer spring by compressing it to coil bind before installing?.... or will that make it so short you can't reach maximum power?....

Bob

The springs don't change enough to matter. Actually the stock spring is to long. I use shorter springs

[steveoh]

I drained my Texan’s tank and removed the fill nipple and the gauge. I found suspect black Teflon tape bits all over.

I have a couple stainless fill nipples on hand and compared to the original Texan they are or appear to be more robust and sophisticated in their machining. Wrapped the threads with yellow Teflon tape and easily installed it.

There is a box of gauges that Alan (AGG) had sent to me that I have gleefully picked through and used to fix crappy tank and compressor gauges. Salute!

I found several Airgun gauges in the box and picked out the purtiest one and wrapped it with yellow Teflon tape and filled the Texan tank to about 2k. Leak. dangit. I tried tightening a little but that didn’t fix it. So drained tank again and saw that my taping job the first time around was poor. I was way more careful the second time. Filled to 1k and no leak. Filled to 2k and no leak. Reinstalled the tank, and filled to 3k and so far it’s holding.

I noticed at the beginning of the exercise that the simple fill nipple had a very difficult to move pin. Flip it over and you see the pin has a star head screw and a slot. Even off the tank it was sticky and hard to turn. For sure it is wonky and a source of some of my problems.

Tomorrow I’ll check to see if the tank held air over night and I’ll set up the chrony and see if I get my old consistent shooting.