Weird thoughts and ideas, not spoken before
My gun was shooting real nice, just where I wanted it. Not being all that power hungry, I opted to shoot at 900fps. The gun was set up perfect, 2300psi fill power wheel at 3, a real nice 900fps curve. 880fps up to 915, back down to 880, a nice 900fps average.
Today not happy with my shooting at sparrows at 55 yards, I took a few shots over the crony. I lost my curve, it started at 925 and worked its way down..no curve it vanished.
All I can think of, is that I had taken a few shots with no pellets in the gun. Perhaps because there was no back pressure the spring inside the valve moved, I don’t know what happened.
Now after shooting over the crony I have to fill to 2500psi and pw=2.8 to get back on a nice 900fps curve. My hammer sure did not get any heavier and the spring sure did not get stonger, but something changed.
So for the first time ever. DO NOT SHOOT WITHOUT PELLETS.
Ideas what caused this?
There is a simple mod out where you put an oring behind the tophat. I think this is a good mod as it keeps you from beating the valve to death. Although I’m not hitting it hard enough to cause any problems.
For the heck of it, I put an old breech oring in front of the tophat between the tophat and breech.
Instant whimpy 425fps gun from a 50fp gun down to under 12fp. The only application I can think of for this is for basement/backyard play. Perhaps if invited into a barn to pest pigeons, can’t be making holes in the barn.
So- Oring in front of tophat for super low power play.
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Viewing 12 replies - 1 through 12 (of 12 total)
You have the TT tuned valve with the light hammer right?
TT valve Condor 65gr hammer/spacer combo.
Do you fill from a tank or a pump?
Shoebox #248
If the spring retainer is screwed in tight the valve spring is under quite a bit of pressure already, I don’t see it shifting since the brass retainer nut has a step to keep it in place…
The spring could have rotated causing just a little more tension on the hammer. But that is reaching…
Maybe the anti ping device on the spring fell off… 😆 😉
Thats it! In fact I put on 10 extra ones and some spring tar, all ping gone….joke 😀 😀
Weird is right!!! 😕
I think you may see another change at some point.
As long as its workin ok, I will leave well enough alone. I will crony check it again in a few weeks and if it changes again, I will tear into the valve.
Sounds like your conditions are pretty stable.
You have the TT tuned valve with the light hammer right?
Do you fill from a tank or a pump?
If the spring retainer is screwed in tight the valve spring is under quite a bit of pressure already, I don’t see it shifting since the brass retainer nut has a step to keep it in place…
The spring could have rotated causing just a little more tension on the hammer. But that is reaching…
Maybe the anti ping device on the spring fell off… 😆 😉
Weird is right!!! 😕
I think you may see another change at some point. 🙁
Now, I have to fill to 2500psi and pw=2.8 to get back on a nice 900fps average curve.
It was 2300psi with pw=3 for that same nice 900fps curve.
Its like my hammer magically started hitting the valve too hard, not from crud in the hammer area, that would slow down the hammer slap and cause less power, not make it hit harder. So I had to add more pressure to the bottle to counteract the hammer hit. It was still hitting too hard at pw=1 to get back on the curve at 2300psi.
Same hammer, same hammer spring, I figure its gotta be something in the valve that moved-shifted or something valve related.
Just weird, but all is well now, and I for one won’t be shooting the gun empty anymore.
All crony work in basement at 10 yards, lighting conditions, temp, all real close.
😕
880-915-880
Then
925-?
It’s a 1% rise in fps from 915 to 925.
And a 2% rise in fps from 880 to 925.
The speed of sound changes by almost 2% (1.8%) for every 20 degrees F… Or 0.9% for every 10 degrees F.
Was there any difference in the lighting on the chrony from the initial tests and the later tests. Maybe from straight sunlight to mixed indoor and sunlight? Was the chrony fully opening the first and second time. Battery power? Any difference in the pellets? Perhaps a newer lot, lube? Could it have been 10 degrees difference in room temperature? Etc, etc…
On a springer if you dry fire you can mess up the system and you can feel a noticeable difference in the cocking lever. On a TX200 the lever will actually hang lose by quite a bit when it is removed from the capture point and the thing will not fire properly at all, the change is far more than just 2%.
What did you do to get it back to normal? 😕 😯
I have been running an oring behind my top hat for 2 years or more, way more efficient and consistent.
and i have dry fired my gun since day one , with no problems.
So did you look the tophat over really good to make sure its not loosened up and moved from where you had it adjusted???
I have heard for as long as I remember you don’t fire these PCP’s empty…
The fact I know nothing of how your rifle is setup or anything would just have me shooting in the dark here anyway… Just wondered if you figured out why yet…
Something else you might want to make sure your breech is all nice and lubed up with something like dry molly so as to have it sliding good in the frame and barrel
Tophat has not moved.
I have never read not to fire these pcp guns empty.
Maybe i’m a big dummy but its new to me.
So, DONT FIRE EMPTY for anyone reading this.
I’m not sure what happened, but all is adjusted and back to normal. Perhaps some minor valve keeper damage or return spring spin, don’t know but all is well now. I’m back to my 900fps and happy.
Mr. N
So did you look the tophat over really good to make sure its not loosened up and moved from where you had it adjusted???
I have heard for as long as I remember you don’t fire these PCP’s empty…
The fact I know nothing of how your rifle is setup or anything would just have me shooting in the dark here anyway… Just wondered if you figured out why yet…
Something else you might want to make sure your breech is all nice and lubed up with something like dry molly so as to have it sliding good in the frame and barrel
You guys are missing the point.
There is not much temp variance in the house and I don’t plan on touching the top hat..the pw maybe. I don’t plan on shooting like that at all. Its just something to play with, who knows maybe you could get 75 low power shots like that.
It’s a 50fp gun down to less than 12fp with a simple oring.
A simple talon/condor to edge power conversion in 2 seconds.
No real reason or practical application for it, other than just to play and perhaps watch the pellets as they fly.
Its just a thought I have not seen mentioned before.
the o ring will slow things down considerably. you just have to adjust the top hat out to get back to the fps you want.
i assumed that the th height was adjusted to compensate. bear in mind when adjusting for this that the o ring will compress a tiny bit, and the bounce will assist in faster closing…these factors may make it so you need to pull out the chrono to get to where you were instead of just adding the height of the ring. once done, however, i have heard of consistency and efficiency benefits, although it seems a bit counterintuitive to me. elastomer compression can be unpredictable, as well as temperature sensitive.
your tune Will change with the temp, and weather change, i just adjust top hat slightly and fine tune power wheel between seasonal changes,
the o ring will slow things down considerably. you just have to adjust the top hat out to get back to the fps you want.
you know, i do wonder bout the return spring. they just dont have adequate stabilization. i eliminated this problem by fashioning a brass flange bearing to put the spring in, and bring it off of the retainer, no room for play now.
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Well thanks for playing… 😆
Shit, i’m stumped… 😀
Keep us updated if anything changes, i’d sure be interested to know. 😉