Adjusting Velocity WHILE KEEPING consistency
I did some very limited testing with softchrono and my condor today, i dint do any full power shots, cause i don have any sound supression, and i dont want cops at my door.
So i checked presure to 2800psi, set the PW at 6, and fired a few barracudas (about 8 ).
Average was 890fps!!! 😯 (they went thru my backstop, and were pretty loud)
i was very pleased with these numbers, except for the fact that i got about 40fps of variation between them 🙁
I know (hope?) that if i turn the PW to say 10 or 12, consistency will improve, but there are times when i want to shoot at lower velocities, say arround 750s.
So to be able to shoot at lower velocities consistently i came up with an idea…
Howbout, i somehow mark the tophat position (by making a little scratch on the valve to align with the tophat screws) as it is now, so i know where to adjust it for full power, and then, using softchrono, i adjust the tophat so the rifle fires at the desired low speed (750fps) with the PW still at 12 to preserve consistency!, i then mark that position on the tophat, and now, every time i want full power, i just adjust it to the other mark (the full power one), and when i want low power, i adjust it to the low power mark.
I would efectively be using the tophat to adjust velocity, instead of the useless power weel.
I dont really need a lot of power levels, 2 would do fine, one that gives me about 970 with 28grain eunjins, and another one wich gives me say 750 ~ 800 fps with light pellets like CPs, gamo hunters, etc.
What do you guys think about that idea?
will it work?
and, do you think theres any risk of wearing out the threads/screws on the tophat by constant adjustment?
any comments / ideas are appreciated.
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Control power by restricting the stem with port bushings (orifice) with the side benefit of good pressure sensing and positive efficient closing of the stem. In my setup a 0.049″ orifice gives say 20fpe while a 0.065″ results in 30fpe.
Walter…..
That is an option. Maybe you can talk to one of these airgunsmiths and see if they can make you a one piece stem and tophat and have them make custom size ports at the top hat end for different velocities.
I let my stem stroke freely through it’s range, use the same hammer, hammer spring and setting.
Control power by restricting the stem with port bushings (orifice) with the side benefit of good pressure sensing and positive efficient closing of the stem. In my setup a 0.049″ orifice gives say 20fpe while a 0.065″ results in 30fpe.
Walter…..
I would be leary of mangling those tiny set screw thingy as well because I have read about top hats coming loose on their own and people have to use Loctite on the threads. Another member also mentioned not long ago about using O-ring behind the top hat which worked well for him.
I like the idea of having a separate tank dedicated for low power shooting. That way, you don’t have to mess with any adjustment. Just switch tank and you have a “different gun” in less than 2 minutes.
Anyway, have fun tinkering.
Adjusting the tophat on that condor valve can beat up the stem pretty well due to it being so thin.
Why do you experiment and try putting some rubber washers or oring behind the tophat. THis will decrease the amount the valve will open and see what it will take to get the velocity were you want it.
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Thanks for your input guys.
So you think its not a good idea to be moving the tophat all the time?
I think ill just adjust my tophat for full power (a 28grain eunjin at about 980fps), and leave it there.
I did some more testing today, and with PW at 6, eunjins go at 832fps average!! 😯
I dont wanna imagine, how fast they would go if i set the PW at 12!!!
I guess my tophat is too open?
what you guys think?
i think ill adjust the tophat to give me the velocity i want (980fps) with the power weel at 10, and leave it there.
As for low power plinking, ill just use my CFX for that.