I half-way agree with Gary. Don't buy a low quality kit, as you'll be buying additional upgraded components later, which is counterproductive.
I think kits are a good starting point, IF, you buy a high quality kit with components that will perform to the task at hand.
The RCBS RockChucker kit comes with a 505 scale... I agree, the 10-10 is better, but there are MANY MANY handloaders out there that have loaded precision rounds for decades with 505 scales. I own both of them, I already had a 10-10, and also have the 505 that came with my kit. I have compared them, neck and neck, and there is no noticable difference in accuracy. The big advantage the 10-10 has is its speed. Its "approach to weight" feature makes weighing charges a lot easier. What that means is that as you add powder to the pan, the beam will begin to move a good ways before getting to the target weight. The normal beam scales won't begin to move until you are within a grain or two of the target weight, making it very easy to over-fill the pan, then you have to remove powder... etc... PITA. When used with a powder thrower, set up to throw charges slightly light (.5 - 1gr), you just throw that charge in the pan, which will be close enough to get the scale's beam to react, then finish filling with a powder trickler.
Nothing wrong with the rockchucker if it fits your needs. I use a Co-Ax, and have been for about 35 years. Still just as strait and tight as day one. The RCBS 10-10 scale is one I've used a little bit, and have always found it to be a good scale. Have used the 505 a little bit. I now use electronic scales all the time. I think it's whatever fits your needs again. But that Lee cast iron press is a good one for most guys to start out with, and they won't break the bank!
Also, he mentioned that the powder measure that comes with the kits will probably wind up being ditched for an upgraded one later... No powder measure handles extruded powder well (stick powder), as it wants to "cut" the grains as you turn the measuring cylinder.... Buying a more expensive "benchrest" measure is going to do the same thing. The Uniflow measure that comes with the kit is perfectly adequate, and is upgradable (you can later add a powder baffle, a $5 insert thats highly recommended; a micrometer dial for more precision with setting throw weights; and different sizes of cylinders, or drums, that are more tuned towards lightweight loads, or heavier loads.)
Also, you are wanting to load precision rounds, as I do - and perhaps you may not be as obsessive over it as I am, but I individually weigh each and every powder charge on the scale before it goes into the case - all powder throwers, usually, are rated to throw +/- .1gr, and to be, that's not accurate enough. I'd rather know my rounds are as consistent as I have the capability of loading them.
You can buy some aftermarket items for the RCBS powder measurer from Sinclair (guess they still sell them). I like the Redding better, but it's no better than a Lyman #55. You can buy a powder bottle adapter for it and various drop tubes to fit your needs. The Lyman will throw ball powder within +/- .12 grains everytime once you learn it mechanics, and it's only slightly worse than my Harrell.
As Gary said, for regular rounds, you don't need a big, heavy duty iron monster of a press... however, you mentioned .300 Win Mag, which you will be happy you have a sturdy press when it's time to resize those. Do you need a big .50 cal press? No. Is a little Lee loader going to flex sizing those .300's? Probably. Personally, I'd get a big single station single stage reloading press, i.e. - Rock Chucker, Lyman Crusher, Hornady LnL, Redding Big Boss or Boss, or Lee Classic Cast. If you can afford one, the Forster Co-Ax presses I hear are awesome.
For dies, I agree with Gary - you don't need to spend $70 - $90 on a die set that requires bushings... Nor do you need to buy "neck sizing" dies... You will learn how to properly set up your standard full length sizing die to do whatever you want it to - you can set it to fully resize the case, or you can set it to partially resize, or only size the neck. I have either owned or used almost all brands of dies, except for Forster. Lee dies, although they worked, I didn't like them. They felt lightweight and cheap to me. That being said, millions of rounds are loaded with Lee dies, and are perfectly adequate. I'm just a snob I suppose... but not really, since I won't spend the money on Redding dies either. I have 2 sets of Redding dies, a .300 WSM set and a .260 Rem set. Are they great dies? Yes, absolutely. Are they worth the extra money compared to RCBS and Hornady dies? No, in my opinion. Most of my die sets are Hornady and RCBS, and they are what I will continue to buy. I only have two sets of Lyman dies, one for .22-250 and another in .40 S&W. Do they work? Yes, however I "feel" that I have more control and precision with the other dies. I haven't tried the Larry Willis dies that Gary recommended, so I can't comment.
The Inovative Tech die I mentioned is a specialized die made for resizing nothing but the belted area on the case. The normal dies will not do this. Eventually you'll need one. The Forster seater is the best out there, and reasonably priced. I like the Forster sizing dies, but others like RCBS. Some others like the Lee collet dies (I don't). I honestly can't see where a Redding die is any better than a Forster at 2/3rds the price, and the Forster seater is better.
Also, as already mentioned, 2 more tools you'll need that are absolutely a must-have, and 1 tool not mentioned that you will absolutely need. The first two are measuring devices - a set of calipers, either dial (has a round face needle gauge) or digital (has a "calculator-like" display). I prefer dial calipers because you never have to worry about batteries, but digital calipers are easier to read, less prone to error's from mis-reading, and just as accurate. You choice there. The other is a micrometer. A vernier micrometer is especially useful because it is more accurate than calipers (.0001" accuracy vs. .001").. I use these to measure the diameter of my fired case heads to check for expansion, and I have another micrometer called a vernier "ball", that has a round tip, which is usually used for measuring the case neck wall thickness. You can spend $25 on a Lyman set, $60 on a RCBS set, or $140 on a Starrett set; your choice.
I think that at last count I own eight sets of calipers in various sizes. Most of my reloading is done with a very old pair of Mitutoyos (4.25" ones), and tey reside in my range box. Bought them in 1970 for the salty price of $71. You can buy the digital 6" version for about $117, but have never used them so I won't comment on the good and bad about them. I use Brown & Sharpes and Starretts (digital). I like the Starretts best. But I loath the analog Starretts in a very big way.
Last, a headspace gauge. Every rifle will vary from one to another in exact chamber dimensions. You'll need a headspace gauge to measure your fired cases, which will have stretched to perfectly fill your chamber, giving you its exact dimensions, allowing you to properly adjust your sizing die so your reloaded cases fit the chamber with a minimal amount of free space... Fully resizing every time allows the brass to expand much more every time it's fired, causing you to lose accuracy and degrade case life. If it gets sized really bad, and has a lot of free space (excessive headspace), it can damage the rifle, and possibly you too. Loading rounds without a headspace tool is like loading in the dark - you are just guessing. Google "headspace" and you'll see much better explanations than I can give. You can get the Hornady LnL Headspace Gauge, which comes with bushings that cover most calibers out there, a Sinclair shoulder bump gauge, which is more expensive, but is a better tool, or an RCBS Presicion Mic, which is my favorite, but is caliber specific, so it gets expensive at around $55 each. L.E. Wilson makes headspace gauges as well, for about $25 each that are caliber specific, and lots of people recommend them, however I've never used one but a few times in the shop - I prefer my RCBS and Hornady sets.
maybe a little late on this post, but I picked up a secound set of headspace gauges (Stoney Point / Hornaday) for $25 at Gander Mountain the otherday! They also had the seating depth gauge and a few modded cases to select from. I use mine all the time
Hope this clears some things up for ya.
Oh, and for long range big game hunting, I have 3 words for you - Barnes Tipped TSX. They are expensive, since they're made out of solid copper, but I have shot everything from deer with the 62 and 70gr. .224" TSX and T-TSX's, within 25 and 270 yards, and also deer up to 670 yards with the 168 and 180gr. .308" TSX and T-TSX's with the .308 and .300 Win Mag. I've never seen one break, and all of them drove a straight path through bone and muscle. There's plenty of other bullets out there that'll suit you, but these are my number one picks. The Berger VLD Hunting line of bullets are also great, although I've only used them in .243 Win on game, and at 230 yards, performed wonderfully, although I'd have liked to see better expansion/disruption. Nosler Accubonds, Ballistic Tips, Hornady SST's, Interbonds, GMX's (solid material, similar to Barnes TSX), Sierra GameKings, Speer Trophy Bonded Bear Claw's, are all outstanding high B.C. long range game killers. I'm also a big fan of the Nosler Partition, however I wouldn't advice them for long range use, since they are lead tipped.
For long range hunting, the most important aspect is your skill and ability. That's more important than caliber selection, bullet selection, optic selection, etc. Only take a shot that you know you can hit 99% of the time. I do most of my long range hunting with a custom .300 Win Mag, that started life as a Winchester M70 Laredo, is now set in a precision stock, has a 26" Lilja barrel, Jewell trigger, and my own custom tuned receiver and bolt... I have taken whitetail up to almost 700 yards with it, but on that particular day, there was no wind whatsoever, I was in an area where I could take my time, and I knew I could make the shot... I've passed on way more shots that I can count that I could've probably made a clean kill, but I feel that the animals deserve more respect than "probably".