Re: Which long range bullet has best ballistic performance for mid to
I think that the problem your going to run into is the term "BEST" is different from one shooter to another and what the intended targets are. For critters, somethig that shoots under 1/2" out to 200yds is generally decent enough. for paper punching, something which will go into 1/4" or less at 100 is what folks look for.
Overall, the short 6mm's shoot lights out, however so do several of the 22 cal's as well as the higher calibers. For the ranges your suggesting, the .223 - .243 caliber rounds will suffice very well depending on the intended target, bullet weights, velocity, and conditions at the time.
Personally, if I were looking to put together a decent 200yd or so varmint rig that I was going to shoot the day lights out of I would go with a .223 or .223 AI with a 1-12 twist. I really do not see a need for the faster twist and heavier bullets out to 300 yds. A 55gr bullet in this round is pleanty for great accuracy and decent performance on medium varmints. Factory ammo is cheap, components are cheap and available in several makes, as well as if you really want to pinch pennies, there is a ton of surplus stuff out there.
I have a Contender that shoots a hell of a lot tighter than I can hold it chambered in 223 AI. It has shot several groups under 1/2" at 200yds and this was with Winchester 45gr factory .223 loads. In fact, I have had it for 8 years and only put about 50 handloads through it due to this. It is just so much easier to grab a handful of the factory stuff and know it is going to shoot so well, I don't even bother loading for it. I do have a ton of formed cases though, should I decide to.
Bottom line is there are a lot of inherently accurate rounds out today and with the available components, and loading hardware, it is truely amazing what sort of groups can be turned out with some careful handloading. Not only this but even the factory stuff is **** fine from what it was ten years ago. You will just have to decide on what your furtherest ranges will be, how much you want to shoot, and just how detailed you want to get in the loads. That however is the fun of it all. It really doesn't matter what you pick out, if your enjoying shooting it and loading for it you will enjoy the experience.
As for the most accurate of all, based on scores from the matches, I would say the 6mm's, as to just which one, well I am not going to even guess, but the BR and PPC have to be leading the pack.
Good luck and enjoy yourself, no matter what you decided on.