Is there a spotting scope in the $500 range that will work for seeing 270 caliber and up target strikes at 300 yards in most lighting conditions? The scope will be used primarily for target shooting from 25 yards to 300 yards. The targets will be mainly white paper with minimal black aim point.
My Nikon ED50 13-30x50 will do what you are asking. They are no longer in current production, but I have seen them used in the $500 range.
Vortex has a 20-60 Diamondback that will work for you. I've also used the 20-60 Bushnell Legend HD to see 30 cal holes at 300 yards. Only time either of those haven't worked is with heavy heat mirage. Both about a $500 bill.
I have a Theron Saker 15-45x-60mm... light spotter that has worked well. I would say that the 45x may not be usaeable unless perfect conditions, but it is a great optic for the price. Only downside is that there are no other options for eye piece. but it was $300.
Used Pentax is an option too for $500
Right now you can pick up a Kowa 601 body for $259 and a LER 25x eyepiece for just over $200. I just bought one and the 20-60 zoom and I am really impressed. This price for the body is a smoking deal that won't last long.
Nick