Microvibe, you talk of shooting deer at 300-500 yards.
I don't mean any offence, but how much experience do you have at shooting at that range?
Shooting beyond 300 yards is no joke. It requires a rock solid rest, time, correct wind reading (without the benefit of flags), and absolute knowledge of the range in order to get the proper elevation. Try shooting a 2-litre coke bottle full of water at 400 yards sometime, and see what I mean.
I'm a long range competitive shooter, and in our game we shoot .308s exclusively. A properly loaded .308 certainly has the right stuff to consistently kill a deer at 500 yards. Absolutely no doubt about it. You can take it to the bank. In fact, if I were seriously contemplating a situation where I had to shoot 500 yards at deer, my target rifle would be my first choice because I have lots of experience shooting 5-inch bullseyes at that range with it, and I know exactly how high to hold and how to shade the wind for that load. I say this even though I have a highly tuned .300 Winchester Magnum, which is more than accurate and powerful enough for that job.
So my question to you is: how well does your Midland shoot? If you can get the first three shots into one inch or less at 100 yards every time, then you have marginally enough accuracy to do the job on a deer at 500. In reality, you should have more, and it's no great trick these days to get better accuracy than that for the first 3 shots, which is all that is needed for hunting rifles.
However, accuracy aside, shooting skill and experience is the most important factor in shooting at animals at extended range. I'm going to come out and say this, even though it's harsh: anyone who goes out and buys a magnum rifle and starts taking pot shots at animals at 500 yards without extensive practice at that range, including, ideally, some competition experience, is a moron, plain and simple. The great thing about the .308 is that it's generally accurate, easy to load for, common, and is the standard competition cartridge. All of these factors make it possible to get the experience for long-range shooting. (By contrast, I don't know of any DCRA range that will allow a magnum cartridge.)
The simple reality is that few people ever see deer at more than 300 yards, and if they do, they almost always have the chance of getting closer.
So here's the short answer again: a properly loaded .308 or .30-06 (ie with the exciting new bullets like the Nosler Accubond or Barnes TripleShock) will be able to cleanly take any deer at 500 yards if the bullet gets to the right place. The problem is getting the bullet to the right place when you're shooting from that far away. That problem is HUGE -- far bigger than the miniscule differences between the choice of cartridge, scope or rifle model. And the ONLY way to overcome that problem is through lots of shooting at extended ranges (which is a humbling experience, believe me). However, if you are serious about practicing at extended ranges, cartridges like the .308 and .30-06 are very practical, economical and user-friendly.
