I'm not an expert by any means. I use this site sometimes: http://www.bestcrossbowsource.com/crossbow-arrow-ballistics-calculator
If you plug in 400 grain arrow and 400 FPS, you get 18 inch drop at 40 yards. 400 grain and 450 FPS, you get 15 inch. So, 3 inch difference.
More FPS will make the bolt travel further before it hits the ground. The trajectory will be flatter.
What I don't know is, could you sight in at a single distance (say 30 yards) and know that you would be within the kill zone at 0-40 yards. I agree, that would make it "worth it". I limit myself to 40 and it would eliminate the need for a range finder (or at last minimize the need to get a precise accurate range).
If you plug in 400 grain arrow and 400 FPS, you get 18 inch drop at 40 yards. 400 grain and 450 FPS, you get 15 inch. So, 3 inch difference.
More FPS will make the bolt travel further before it hits the ground. The trajectory will be flatter.
What I don't know is, could you sight in at a single distance (say 30 yards) and know that you would be within the kill zone at 0-40 yards. I agree, that would make it "worth it". I limit myself to 40 and it would eliminate the need for a range finder (or at last minimize the need to get a precise accurate range).