WOW, let me see if I can touch on these for you.
TS is absolutely correct, top gun will not make you a good shooter, but it will prevent a good shooter from shooting rat shit in a dresser drawer.
Weapon/optics
Barrel, needs to be heavy enough to not whip but not so heavy as to be unwieldy. Forget flutes, they are a way to make money for the gunsmith. The barrel on the M24 is about the limit on thickness and that is pushing it a bit. The bore needs to be enough to have a good throat but not so new as to have not settled in, a reason for the first 100 - 150 rounds. Once the throat starts to erode you have problem with free bore but you do not want to pre-engrave the bullet by making the throat too tight. That horse is dead, it also leads to making it so tight that the care becomes pre-engraved, which in turn pinched the bullet and you get one hell of a pressure spike, not good for gun or shooter, let alone accuracy.
Barrel needs to be free floated and allowed to vibrate from the round and explosion that just took place. The ideal situation is that the barrel harmonics allow the round to exit the barrel in the same point of the sin wave. I use sin wave loosly here, as the wave can be on any plane around the barrel and in some cases loops around the barrel as the bullet spins down the barrel. This error is measured in MOA and is more pronounced as the range increases. Anything, and I mean anything that disrupts this harmonic will cause a loss of accuracy. This is usually a shooter error that allows the barrel to become trapped and not vibrate freely.
Action and recoil lug needs to be fixed, usually by bedding and only the rear of the recoil lug will touch the bedding/stock. If the action begins to shift in the weapon due to collapsing bedding, crushed wood/fiberglass, then as the action shifts so does the alignment of the barrel.
Stock needs to fit the shooter so that he can get a natural stock/spot/cheek weld. This sets the eye relief which sets the sight alignment. Sight alignment errors are measured in MOA and as with above becomes a greater miss at longer ranges. Sight alignment plays in scopes as with iron sights, when you do not have a parallax adjustable scope.
Scope rings, buy good ones, cheap ones will loosen or break at the worse possible time, and will not hold zero or will not return to zero if the scope needs to be removed. An example is the Redfield ring/base combo on early SWSs. The scope rings were not fixed well in the base and the rings would begin to drift.
Parallax error is measured in MOA but to see the actual error, look through the scope and wiggle your head, when you see the cross hairs move from one side of the target to the other, and off the target, that is your potential error. Very important. When we did not have parallax adjustments, I would wiggle my head and make sure that I not only did not have shadow, parallax indicator that your head is not aligned properly, but that the reticle moved evenly left right up and down on my target, took a second, but helped negate the error.
Handloading is all about consistency. All cases should weigh the same. Why, because a difference in weight means that there is a difference in case capacity which means there will be a pressure differential. That pressure change is a MV difference. Also, powder charge needs to be trickled to the correct weight, again MV changes if you have a change in powder weight. There are so many little things in handloading that will bite in when you are looking to accuracy. From touch hole being clean and concentric for even powder burn to case length for the same free bore shot after shot.
Bullet weights are important, I shot 77gr for 200 and 300 yards, and 80gr for 600 and 1000. Most people shoot the round that gives them best overall. Along with that bullet weight is the powder charge for the different bullets, of course I had more powder for the 80gr and wanted a round moving to buck the wind, for the 77gr I lowered the powder for not only the bullet, but so that during rapid fires my sights would not leave the bullseye.
Ballistic hollow points were originally made by swagging the bullet from the rear and drawing the copper gilding to the point. This created a bullet with less turbulence in the rear and thus less drag. Through experimentation and never letting things stay too stagnant, several of the bullet manufacturers moved to a plastic tip to move the CG more to the rear. This helped in some things and hurt in others. When a bullet becomes over stabilized it acts as a gyroscope. When this happens as the bullet falls back to earth it will still stay nose high due to the over stabilized bullet. This leads to other problems when wind, pressure changes, etc hit. It also is the leading cause of key holing besides shooting the berm.
A rearward shift would not effect interior ballistics, but the VLDs and semi bore ridding bullets does and they are finicky as hell due to it. I would leave them out of the mix unless you are very good at reloading. The rearward shift can effect exterior ballistics especially in the case I sited above where the bullet starts flying butt low/nose high.
That should get you started. Let me know if I can answer more questions and if these help. When you start to talk about extreme long range, then a whole new set of problems set in to include the rotation of the earth.
