Help with Talondor Velocity Inconsistencies. …PLEASE
Hey guys,
I have got my Talondor together and started testing with JSB Kings. It is accurate when the velocity is close together but I am having some velocity inconsistencies. It shoots in the high 800fps to low 900fps range. The velocity is exactly where I want to be but I get a 700fps shot every 5 or so shots in a 10 shot string. I have disassembled it and polished the inside of the frame, hammer, barrel where everything rides and used some dry graphite as lube. As well as disassembly of the valve and polished all of those parts. I have Tony’s QCTH and am using the large restricter. I have varied the fill pressure on different strings. Problem still there. What could this be ? I have shot about 500 pellets in between trying this and that to no avail. WTF ? PLEASE HELP !!!
All Replies
Polishing the stem is definitely a good thing to do.
Ok, being that you’ve tried almost everything else if it were my gun I would do this: Order a direct flow valve seal from Air Force and install it. The seal is a little longer so you won’t be able to screw in the retaining nut all the way but I’ve set up a lot of guns up this way and they work great.
Also a little heavier V return spring and heavier shorter (3.5″) hammer spring would also be good things to try. My favorite Air Force Gun is set up that way and it will shoot one ragged hole at 50 yards all day everyday.
The direct flow valve seat and new breech slide Air Force recommended may solve your issue but if you wanted to try the heavier Springs PM me in a couple of weeks and I could send you some to try.
Thank you for taking the time to look at this tagdagger.
I can’t speak for JIm but I’ve looked at all of these
It happens with both the AF and TT tophats
I took a coil out of the spring, it happened before the mod and since. It happens if I run the shortened spring at pw1/1
I’ve used the TT hammer and the factory hammer & weight
AF have suggested a faulty breech so I tried this again this morning. As before lubing the breech gave a limited improvement for a brief time. As time increased so did the extreme and the frequency. Before lubing a 100fs variance was not uncommon with 40 to 50 fps being the norm.
I shot two strings, one at twenty four shots and one at sixty five shots.
In the first twenty four shots I had 14% or seven shots that varied from the previous shot by 16fps or more. They were as follows;
#22 840 +18
#17 838 -56
#16 894 +49
#15 845 -15
#12 850 -18
#06 859 -22
#04 874 -16
In the next sixty five shots I had 44% or twenty nine shots that varied from the previous shot by 16fps or more. They were as follows;
#65 736 -29
#64 765 21
#63 744 -47
#62 791 57
#61 734 -69
#60 803 59
#56 757 -29
#55 786 25
#54 761 -45
#53 806 62
#52 744 -23
#44 773 -47
#43 820 46
#42 774 -49
#41 823 -20
#39 839 -18
#38 857 63
#37 794 -48
#36 842 44
#34 794 16
#33 778 -70
#32 848 -16
#30 856 64
#29 792 -53
#28 845 53
#25 810 25
#21 797 -17
#18 813 -18
#14 814 -32
#13 846 22
#12 824 -40
#11 864 21
I pulled every thing out yesterday and rechecked the frame and components. As far as I can tell the stem’s not bent, I posted photos earlier, but its not the best finish. Will I be ok putting it in a drill and taking 1200 wet and dry to it or is this too aggressive?
Here are some of the other things that could cause radical velocity fluctuations.
1 to much Top hat gap or a loose top hat.
2 to much preload on the hammer spring ( causes excessive hammer bounce and subsequent burst of air)
3 Hammer is not heavy enough to open valve consistently.
4 damaged or un- lubricated orings in breech slide.
5 Something binding or dragging- eg.. bur on gun frame,(especially in breech area),damaged or broken derin on hammer,bent valve stem,or bur on valve stem.
Thank you gentlemen, your suggestions are very much appreciated. This morningI took the valve apart
The valve spring retainer was tight and thread sealed in place
What spring poundage should I be looking to try? And for that matter what’s the poundage for the original spring?
It may take me a while to source an alternative spring to experiment with so in the mean time can I increase the spring tension by putting a shim behind it?
I’ve attached some photos of the delrin seal. What’s your assessment of its condition?
Whilst the problem is really frustrating, it has forced me into a situation where I’ve had to go much deeper int the gun than I would have anticipated and I’m thoroughly enjoying the learning curve
For a non-regulated gun Valve dwell time should be short and quick especially for a valve stem that moves a lot of air like the TT one.
Yeah that too! Make sure the delrin seal on the inside of the valve is not worn. I think it has a 45 degree angle for the seat. A heavier valve spring will help too. I am still learning/understanding how AF rifles work, so somebody correct me if I am giving the wrong information.
Thank you tagdagger, that sounds well worth investigating.
Please excuse my ignorance but is the retainer the brass fitting on the bottle side of the valve or the plate on the top hat side of the valve?
I haven’t undone one so I don’t know if its possible but assuming its the inner one, would tightening the retainer more than normal and therebye increasing the load on the valve spring have the same effect as fitting a heavier valve return spring?
When I had the valve out of the bottle I noticed that on one side of the inner valve body there was a channel in the thread but I didn’t examine it carefully. Is this peened over to prevent the retainer from becoming loose or is it to a release pressure in the event that an attempt is made to remove the valve while it is still under pressure?
I’m sorry I can’t give credit for the photo, I don’t recall where I got it from.
Attachments:
It would be worth a look to see if the valve spring retainer has back out some. That would cause what you are describing, even if it hasn’t trying a little heavier valve return spring could solve your issue.
For a non-regulated gun Valve dwell time should be short and quick especially for a valve stem that moves a lot of air like the TT one.
If you need a spare TH, let me know, I have 4 different ones you could “try to buy”.
Rick
Either the material was too hard to turn or the tool bit was dull when they were made them. I “think” air is inconsistently escaping when the tophat is depressed. I am a machinist by trade to qualify what I said above.
Thanks Rrdstarr, I don’t know much about these things but I was expecting it to have a highly refined, polished finish which is why I asked.
That said I had same issues albeit to lesser levels with the AF top hat. I’ll swap back to the AF TH, test again and post the results.
Those tophats don’t look right!
Either the material was too hard to turn or the tool bit was dull when they were made them. I “think” air is inconsistently escaping when the tophat is depressed. I am a machinist by trade to qualify what I said above.
No breech play. Already checked that. Thanks for the response it is greatly appreciated.
Breech play maybe ?
When closing the cocking bolt to the side cutout, after which is there a front to back play ?
~ Greg
Mine has the same marks as yours. So here is a string I shot using Tony’s recommendations.
TH-LR PW- 8 HNBR 3/16 X 5/16 X 1/16 Oring under TH JSB MKII pellets.
2800psi starting pressure
762.6
552.0 WTF ?
772.3
777.6
784.2
781.7
788.5
789.2
791.1
789.6
2700psi
796.0
787.5
794.7
793.9
797.3
798.2
798.9
796.6
800.5
797.7
2550psi
737.0 WTF ?
772.5 WTF ?
795.0
792.8
797.4
793.8
746.6 WTF ?
792.2
791.3
780.3
2450psi
789.8
771.7
792.3
789.2
767.0
791.8
785.5
783.9
785.6
760.1
2300psi ending pressure.
Still having the random inconsistencies.
WTF is causing this ?
I didn’t have these issues with the Talon valve. It all started after swapping in the valve internals to the Hiflo. I replaced all of the valve seals with AF seals purchased from AF. It doesn’t leak as I tested for leaks by submerging in water with no bubbles. I am trying to get 20 or so shots at 800-850fps for hunting. Can anyone help me out with this issue ? Tony, PLEASE HELP ME!!!!!!! You can contact me at 304-582-4970 Thanks, Jim
PW at 7- 8.
Check for bent valve stem……
I’m having the exact same problem as Bullseyeft in fact we’ve been exchanging information on it.
I ran through your suggestion on both 7 & 8 and the problem is still there.
As you suggested I checked the Talon Tunes Quick Change Top Hat and noticed these marks. Could this be contributing to the problem?
- You must be logged in to reply to this topic.
tagdagger, thank you so much for these suggestions
1200 wet & dry?
Ok I’ve ordered one and AF are sending me a replacement breech
Oh yes please, that would be fantastic. I’ll pm you for the details
Basically I’m up for trying any thing that you recommend. Thanks again