Welcome to the site!
I'm sure you will get a bunch of different responses and ideas. Here is my thought:
Your gun is shooting good. No sense messing with it (yet). Once you learn what you do and don't like when shooting LR you can start making changes.
On to your scope. I am a little torn here, so I'll put two options out there:
#1. Grab a spotter and go see how far out you can make MOA hits with your set-up exactly as-is. Use the BDC to the best of your ability. Determine if you want more mag, prefer dialing over holdover, if you might use variable power and would get value out of a FFP scope, etc. Basically, see how far out you can get on targets and see where and how you begin to fail, and let this lead into your decision on a scope (and a quality rail and rings!)
#2. Do some research and buy a reputable LR scope. Decide if you are going to dial and hold MOA or MIL and buy accordingly. Check out the classifieds here - good used glass will save you a few bucks and will hold its value should you decide the price isn't worth the performance. I'll bet you won't - good optics are worth every penny. I have NF scopes for long range, and Swaro Z5's that I take out to 700yds with the BT. Vortex scopes also get good reviews. Buy once cry once. Get a high-end 20MOA rail and good rings, and go shoot.
I lean toward #2 because I think a new scope is inevitable, and it will help you learn and catalogue the drops of your rifle better (relative to the limits of the BDC option). But, knowing the limits of your current equipment is also valuable in choosing new gear - plus it helps remove any buyers remorse when you take your new stuff in the field and see immediate benefit.
Once you get through your new scope, you can again push your limits and assess what (if any) changes you want to make to your rifle/loads.
Good luck and have fun!