Re: success stories?
Your 200 yard muzzleloader kill is a nice accomplishment - was not long ago that 100 yards was the max and even that was considered a long shot. Now we are regularly killing past 200. Recently we have started shooting out to 300 with good kills. Makes a hell of an arc but the bullets are killing nicely if you place them.
Your centerfire rifle will do fine, just get out and shoot in the wind and learn as much as you can.
We killed a lot of deer in the 500-600 yard range this year on a CWD cull, lost count of the longer shots but it was probably about 12-15, three kills at 700 so far. One fellow we introduced to the game made two consecutive kills at 700 yards with a brand new M-70 Stealth.
All of our rifles are .308 Win. I use the Leica 1200 and a Bushnell 1000 on the hunts, we split into two pairs usually. One guy spots, calls wind and elevations and gets to see the deer bite the dust. The other guy just concentrated on shooting well and we did not have many deer that required a second shot. Most shots were from prone, using Harris bipods.
Scopes we used were two Nikon Tacticals in 2.5-10, a 3.5-10 Leupold Tactical and an NXS in 3.2-15. Ammo was BHA Match in 175 BTHP and handloads with 168 Nosler Comp. Supremes, 168 Barnes Triple Shocks and 150 gr. Hornady Interbonds. We did not recover many bullets, at 500+ the bullets always exited.
All the rifles have Badger mounting systems. We also have drop charts on the side of the rifle or in Eagle stock packs, use the nifty Ballisticards whenever we have the BHA ammo out.
We spend a lot of time getting good drop charts, that is one big reason why we killed about 40 deer so cleanly. All the heads go for testing and the meat is consumed when OK'd.