Hi Joekool,
i have decided to,start testing with the WC MK3 before I have a ( well fitting ) plenum extension . The reason for this is that I found a youtube cideo of Matt Dubber in which he explains about the development of slugs and slugliners from him in cooperation with FX. He advises to have the reg up to 150-160 bar in case one shoots slugs as this high reg setting avoids air turbulence behind the slug during its travel through the barrel. He says a higher reg setting avoids the air still making turbulence when the slug leaves the barrel. The quick opening and shutting of the valve due to high reg setting is essential for small groups he states. Now I want to ask you about this theory .
i would think that plenum extensions would make lower reg settings possible what is nice for more economical air usage and more quite functioning of the system but.... does this not work counterproductive in terms of the theory of preferred high reg settings from Matt ?
the shorter the barrel the more critical is this avoiding of air turbulence behind the slug I would think. As witg ahorter barrel you have kess time to open and close the valve before the slug leaves the barrel.
I would normally have started testing with a reg aetting of 120 but I have decided to bring Matt’s theory to the test and start with reg on 145. No plenum extension . So standard WC MK3. In .22.
first shots were low 590 f/sec. In position 7 on the powerwheel . I turned the spring anti clockwise till and ended up with 950 m/sec and then turned it back to 930. I found that in case I would even more turn it anti clockwise the cocking handle would get stuck. If I give the spring toomuch tension the gun would not load a slug anymore nor cock ...It feels if somethng is going wrong but when you turn thenpower wheel down to 5 for example everythings works smooth again. Can you please comment / give tips based on your rich experience . For me this is my first FX and I want to learn as you might have experiences already. Mainly the high reg setting theory for best groups ( no air turbulence behind slugs when leaving barrel) and the plenum extension advantage / disadvantage when shooting slugs inthis context of Matt’s recommendations
below you find the lonkmto the Matt Dubber video I relate to .
https://www.youtube.com/watch?v=TLK5j2urOJ0&feature=share
thanks in advance
yalel
I have seen Matt’s video/movie 20,000 times (it seems, Youtube algorithms!). I feel and know he is absolutely right in everything he says about getting the best from a slug liner vs slugs. He helped develop them, so he’s undeniably one of the most knowledgeable on FX slug liner tuning. I don’t even pretend to know as much as he does about airgun marksmanship.
Fusing some of what he states and what I have experienced. This is what I will say, in layman terms and its simple.
- A high regulator pressure will give you similar energy and accuracy when tuned or balanced well with your hammer spring tension. But, the airguns block and firing valve will be under higher stress do to the high regulator pressure and how much harder the hammer will have to strike the valve (a higher regulator pressure, the valve is harder to open). There is always a limit (a reg. pressure limit and a HST limit).
- Added plenum space and/or air volume allows you to flow even more air with a lower regulator pressure producing similar energy as a higher regulator pressure would produce. But, with less stress on your airguns block and firing valve due to it not being necessary to have as much hammer spring tension to open the firing valve (it would be under less pressure) More plenum space equates to = with less pressure , you can get more energy. Larger plenum volume can maintain an airguns docile feeling shot cycle but give an very impressive energy increase. Feels smooth and yields less gun movement upon a shot. Better efficiency due to a lower operating pressure.
Pros / Cons / Things I find true
-Large air volume (more plenum space), less regulator pressure, and a balanced HST can equal more energy with good accuracy.
-Higher regulator pressure and a balanced HST can equal more energy with good accuracy.
- Low reg. pressure & larger plenum, shoots more gently aka smoother than High regulator pressure with a small amount of plenum space.
- Accuracy comes from balance, balance, did I mention balance. You need just the right regulator pressure vs just the right amount of hammer strike to open your firing valve for just the right amount of time. Per your barrel length to give your projectile the desired or proper speed to leave the barrel with no wasted air/turbulence. All this will equal harmony, efficiency, good energy, And if you’re lucky good accuracy.
-Too fast isn’t good, but you need to determine what is too fast by testing, tuning, shooting your own airgun.
-High or Low regulator pressure it still boils down to: balance + harmony = accuracy
-Power tuned or tuned down it still boils down to: balance + harmony = accuracy
-Barrel length is a big factor.. Short barrels will only produce so much energy before they hit that brick wall of turbulent air when powered too high. Throwing most hopes of any kind of precision off. (Balance!)
-Longer barrels are more forgiving, have more runway to build up projectile speed, could produce more power at the same regulator pressure as shorter barrels, but will suffer the same issues as a shorter barrel if there is improper what??? “Balance!”
-
5 bar just
5 bar can make a huge difference in group size. When tuning try adjusting regulator pressure up or down 5 bar and test shoot? I have seen a 5 bar regulator adjustment shrink group size numerous times!
My real world example: My FX Crown .25, Huma regulator @ 175 bar, 67-68 fpe, additional hammer weight (allows me to open the valve at that high reg. pressure), 600mm STX Superior Liner, accurate as hell! (Balanced)
My FX Wildcat MKIII .25, AMP regulator @ 135 bar, 67-68 fpe, stacked plenums & larger transfer port, 700mm STX Superior Liner, accurate as hell! (Balanced)
Two differently tuned guns, but both balanced in their individual tunes... Both extremely accurate! Making sense??
-A person can tune their gun up or down and still get accuracy. If there is balance.
-IMO larger plenums are the way to go (easy & efficient power gains and less mechanical & physical stress on the airgun), but if the gun doesn’t give the option of a larger plenum your only option to raise power is to raise reg. pressure and HST, or make modifications.
- Balance... No matter what regulator pressure.
-Never tune for absolute power! (As much possible energy you can absolutely, positively get from the darn thing!) In sacrifice of good efficiency or decent shot count. That’s just a bad tune in my book. There is a limit, going beyond that limit is just a badly tuned airgun.
-Well designed heavier projectiles can handle higher velocities pretty well. It’s the lighter weight projectiles that get unstable at higher speeds. They just don’t have enough a$$ to buck the oncoming wind turbulence. ( JSB .177 cal 10.34, JSB .22 cal 18.13, JSB .25 cal 33.95 love the 900’s from my FX STX, Slug & Superior Liners) But... My airgun’s tunes are well balanced.
-Better to shoot the gun as is then to tinker and muck it up if you don’t fully understand what you are doing. Or let a professional tune it. There is nothing wrong with leaving the airgun well alone and just shooting it the way it comes and using projectiles it was designed to shoot from the factory. I power up my FX PCP’s to achieve things I want the gun to do. Like having a flatter trajectory, the ability to shoot slugs or heavier pellets at velocities that I know they perform well at “FOR ME”, to increase my airgun’s effective range, and the SMACK factor! (Knocking the living hell out of whatever animal I am putting down... Accurately & Humanely.)
These are a few things I have learned through my personal experiences in air-gunning, tinkering, tuning, modifying, testing, and hunting. If they are not true for you then that is okay, just say to yourself, “That’s Bull S##t!” and keep enjoying your life and “use your airguns the way you want to”. No need to argue with me, lol.
JoeKool
. The Huggett 500mm dedicated shroud sounds like a great option.
). Now I will,take it to longer ranges and see how the groups will be 
