does shooting an arrow at 300+ FPS really have that much of a noticable difference in trajectory than let's say an arrow at 250-270 FPS.
There's a lot of ways to argue this +/-, and I don't actually have a position.
I have been picking up arrow speed for the last 40 or so years, and have shot deer with arrows moving anywhere between about 150fps and 305fps.
The differences are incremantal to some extent, and if I had to, I could easily get by with anything going over 250fps as a low end preference. I feel there's a useful difference from 250fps to 270fps, it's not huge, but it's real for a guy with the skill to actually make shots out to 30-35yds. From 270fps to 290fps, the difference is actually less, in my experience, and you pay a larger price in ease of tuning for the additional 5 yds of distance you will gain, and past 35yds, you still need to know far the shot is for precise shot placement. Above 280fps, I can get fixed blade heads to shoot, but above that speed I use mechanicals exclusively. This year I was able to get 75gr Muzzy three blade heads to shoot reliably at 305fps. And I made a nice shot on a large cornfed doe at 30yds with that rig, but I didn't see any big difference between that shot, and the other deer I have taken with many slower arrows.
Next year I'm hoping to draw a WY tag for elk, and if not, I'll grab a OTC tag from CO. I'll be shooting a Turbotec recently relimbed with a set of XT2000's, courtesy of FoggDogg. It shoots a 425gr CAA400 @ 280fps. It took 15 minutes to get it to land a 125gr Slick dead on at 20yds in my basement range, and will easily tune out to 65yds, I'd bet my last dollar. 280fps is my best blend of trajectory and ease of tuning.