Good figures, there , Tom.
Don't know if you know this or not, but that is a PERFECT arch at 45 yards! This means you stay within one inch kill zone for your pbr at 11 to 50 yards! That's about as flat as you will ever get it! Touche, Brother!
In other terms, that's 141 FPE at the muzzle and at 50 yeards, you are STILL at 71 FPE!
Considering the mass that ball is, that's a HELL of a whop at POI.
Get hit with that and a deer would barely have time to say, UGH, then keel over! Whew! Boy, that's good figures!
Now, Air Guns are near/close weapons and 100 yards are capable of being made but my practice is staying at or around the 40 to 50 yard mark. You retain enough energy at that distance, a flat trajectory and it's all over but the reloading---if you have to because of operator error and the point of the near perfect arch is to not have to in the first place.
At 60 yards your enterance to the arch is about -1.75 below line of sight and at your exit of the arch at 60 yards you are at the same identical negative number. Perfect, Tom! Just perfect! I'm not saying that you should change anything from the 45 yard zero---you have to figure the rest of the curve in the arch and that ends, to have it perfect for the numbers I just quoted, you end would be at 60 just like you lose the first 10 on the front side of your first zero with your far zero being at 40 to 50 yards. You only get to use just so much of that curve and you've got a near perfect one: I'd stay with that and realize you can't get better than that unless your up your FPS and I'm thinking that you got it dialed all the way up, right?
Got air gun chair pro? Plug those number in with a range of 60 yards and you'll see exactly what I'm talking about on the graph. Pretty darn cool, my friend.
I think you've found your magic bullet for this one. Any heavier and you'd have to go up in FPS to keep from lobbing it in a really high arch and that would put you outide the one inch kill zone for the part of the trajectory---righ the middle giving you two pbr's. You want to stay away from that---if at all possible. But with heavier grains you'd almost certainly not be able to get that kind of stright line, as much as you can call it straight line during an arch.
I'm impressed, Mr. Tom! VERY VERY good!