That is a great looking gun. Very well thought out, executed and finished. I really like the barrel band---how did you fabricate it?I did some experimenting with the Magnum Air Power valve. This valve as delivered is a good 7/8 tube gun valve, and will easily deliver good power. for ammo up to say .25 King Heavies. IIRC it uses a .125 Mrod stem in a .215 throat, which helps maintain a fairly easy to cock hammer strike requirement. The challenge though, is throat area is only equal to ~.175 port vs preferably the throat area being equal to or 10% or so larger than the smallest port down stream. In .25 and under, this isn't to much of a constraint. But as bore increases and ammo gets heavier it becomes a bit restrictive and you can find yourself excessively leaning on hammer strike to try and counter it with dwell. One of the things I did was convert the valve to a 2mm stemmed peek poppet, leaving the valve throat untouched. This offers throat area pretty close to the 10% greater area target. You will see a nice increase in energy without having to increase throat diameter and in turn cocking effort. Very cool build. I look forward to seeing how things progress when you get your TJ's barrel. I assume you are planning a 1:26? I have a few applications using that particular liner and it has shown excellent accuracy in weights/lengths up to around 150gr or so. Note you are not limited to ordering through Track the Wolf, you can approach TJ's directly via email. tjsliners1992@gmail.com
Quote from: mackeral5 on April 09, 2023, 09:36:03 AMThat is a great looking gun. Very well thought out, executed and finished. I really like the barrel band---how did you fabricate it?I did some experimenting with the Magnum Air Power valve. This valve as delivered is a good 7/8 tube gun valve, and will easily deliver good power. for ammo up to say .25 King Heavies. IIRC it uses a .125 Mrod stem in a .215 throat, which helps maintain a fairly easy to cock hammer strike requirement. The challenge though, is throat area is only equal to ~.175 port vs preferably the throat area being equal to or 10% or so larger than the smallest port down stream. In .25 and under, this isn't to much of a constraint. But as bore increases and ammo gets heavier it becomes a bit restrictive and you can find yourself excessively leaning on hammer strike to try and counter it with dwell. One of the things I did was convert the valve to a 2mm stemmed peek poppet, leaving the valve throat untouched. This offers throat area pretty close to the 10% greater area target. You will see a nice increase in energy without having to increase throat diameter and in turn cocking effort. Very cool build. I look forward to seeing how things progress when you get your TJ's barrel. I assume you are planning a 1:26? I have a few applications using that particular liner and it has shown excellent accuracy in weights/lengths up to around 150gr or so. Note you are not limited to ordering through Track the Wolf, you can approach TJ's directly via email. tjsliners1992@gmail.comHey, thanks for the information! I have been nervous to touch the valve up to now as that work requires a bit more finesse than I'm used to haha, but I am definitely interested in making some tweaks when I'm ready. I have probably reached the limit on valve dwell as hammer spring strength is maxed out unless I come up with a stronger bolt handle and probe. I think reducing the valve dwell and increasing the throat diameters would allow for a much more efficient use of air as I could reduce hammer spring strength which would reduce hammer bounce.I have yet to decide on twist rate for the barrel liner, I'll probably go with the same as Bob went with for his .35 cal double Disco build which I believe was 1:26.If you have any good sources of info regarding tweaking the magnum valve I'd love to check it out.