"amoxom"Anything around 920-940 is about optimal velocity for all diabolo pellet shooting Airguns.. regardless of caliber. Anything faster will tend to generate corkscrewing. YMMV of course. Trajectories should be flatter and very similar if you can keep the velocities as close as you can.
Ideally, moving to a heavier pellet, and keeping velocities up above 900fps will also help down range energy and accuracy. Heavier, and sometimes longer pellets should be more efficient due to better sectional density. They should retain energy better than a lighter pellet.
I've always thought that too because that's what I was told but then I read about some guy who won some big deal field target competition using a custom .177 Marauder shooting his chosen pellet at 1050fps. He claimed that the extra speed helped him do a better job against the wind. As he won against more experienced shooters who imposed those traditional speed limitations, it made me think it might be a little more complicated than we thought.
I guess the obvious point is that you can use any speed as long as it's accurate. Certain pellet / gun combos do better at low speeds and some at high. The only way to tell is to experiment. With so many different designs of pellet and barrels, it makes sense that there is no one size fits all.
My (limited) understanding is that the inaccuracy is caused at higher speeds not when the pellets crosses or approaches the speed of sound but when it drops back below it mid flight. It's that sudden change that causes instability. At a short enough range, that shouldn't happen as you'd hit the target before the speed dropped below the speed of sound again.
On the accuracy thing at 12 ft lb, it depends on the distance you are shooting. Many of the expensive target guns made for shorter range disciplines are set to lower power / speeds than the match rules allow. One thing is certain though, the trajectory will not be as flat and the difference will become very noticeable past 40-50 yards. Of course, a flat trajectory is not the same as accuracy. It just requires less adjustment for the drop. It doesn't really matter if you have to drop 4 mil dots instead of 2 as long as the poi is consistent. The pellet just needs enough speed to remain stable in flight, unless you hunt.
If I lived in the UK and wanted to hunt, I would be applying for my license so I could buy the fac models. I wouldn't want to hunt with 12 fpe but if I had to, I would stick to birds at closer range.
You can kill other small game with 12 fpe but you need perfect head shots. Personally, I think it massively increases the chances of wounding instead of killing. I've seen a number of squirrels run away injured from less than perfect shots with 30fpe 22's so it's not going to be better with 1/3 of the energy.
