My favorite Aquila ammo is the Super extra blue and yellow box subsonic. I don't have any of the new production stuff, but the new production HV stuff is definitely acceptable and inexpensive as well.
I have a marlin model 80 from the early 70s I installed a 3x9x40 scope and a bipod, I get sub 1" groups constantly, it gets better with CCI AR 40grcprn
This has always been a decent 50 yard setup. I wish it was a little better at longer range, but for what I use it for, pretty much any ammo is plenty good enough out to 50