Well I don't shoot slugs in Air rifles but I shoot a lot of 22LR at 100 yards in F Class. The vertical string tells me that it don't like that slug per se at that distance. Unless you had a really strong headwind or tailwind and that will affect that vertical string. But that could be slugs in an air. I'm just giving you what I find in my 22 rifles for competition. When I'm shooting a distance to see if a certain lot of ammo shoots good I don't mind the left to right dispersion because that could be due to wind but I don't like any vertical dispersion because that's not an accurate lot in my barrel. So you might have to tune it different. Some ammo shoots really great at 50 that falls apart at 100 and people can argue that if it shoots great at 50 it'll shoot great at 100 I don't think that's the case because I've seen it too many times. Also a lot of people get hung up on SD and ES and think their guns gonna shoot good because of low numbers not necessarily the case either. You just gotta shoot it at that distance that you're wanting to shoot out mostly see how it does. Ithis is all for 22 LR which I've done for years and I have no experience with slugs in air rifles. And if you're shooting off a bipod you could be loading it different on shots it could be different grip pressure different cheek pressure when you get behind the gun there's tons of variables. My advice is to get consistent trigger pull cheek weld pressure on the gun and see how it shoots. Some air rifles and other rifles like more pressure or less pressure into the shoulder stuff like that. Good luck it's fun shooting anyways.
Remember follow-through is important to especially in slower projectiles like in an air rifle so the more movement even after you squeeze the trigger just for a hair second can affect down range accuracy.
