You can reload for plinking ammo (easy, cheaper) or you can reload for serious use (more expensive and more time consuming to make sure the loads are both dependable and accurate enough to meet your objectives) or you can reload for maximum accuracy for your rifle (even more expensive and more time consuming).
Accuracy is obtained through consistency. If you don't build it (the cartridges) the same way every time you're wasting time and money.
You should experiment with different brands of primers as these can have a positive or negative effect on your group size. You should try different brands of powders and different burning rate powders and different load weights (remember the limitations of the gas operated rifles when it comes to burning rates) during your load development. You should try different bullet weights and brands. The trial period will probably be expensive depending on how much experimentation you go through to develop a load that satisfies your accuracy "needs". Besides the components the factors you'll need to consider are your case preparation, bullet seating depth and whether or not you crimp the case mouth on the bullet.
Remember, every rifle is slightly different even than the one built right before it or right after it. Believe it. Some rifles approach perfection but most do not, that's why they don't all shoot the same. That's why your grandpa had a pet nickname for his favorite squirrel or deer rifle, because he found one that shot to his satisfaction and he knew he could depend on that one rifle to get the job done.
Most everyone "believes" some steps are absolutely necessary and others are a waste of time. And just like the rifles they shoot, people are different when it comes to what they believe is necessary. Try different things, document what you try (in detail, not just what, but how you did it), refer to your records and you'll develop loads for your rifle that will shoot rings around factory ammo (as long as you practice what you learn at the Appleseed and from Fred's Guide - the best rifle and ammo in the world won't make a lot of difference if you don't know how to put them to work).
Here's some things I do:
1. clean my cases thoroughly before resizing/spent primer removal
2. every now and then during depriming/resizing I put a little lube on the neck expander
3. I run the cases through the cleaner again after resizing/depriming
4. the first time I use military cases I run them through a primer pocket swager to remove the military crimp so new primers will go in
5. I clean the primer pocket with one of the little tools made for that purpose to insure the new primer can completely seat (very important to insure the new primer can be completely seated
6. I trim my cases the first time so they are all the same length
7. I turn the necks down the first time so they are all the same wall diameter (important for two reasons, first for the next step, and second to help keep bullet "pull" consistent - bullet pull is the tension on the bullet the neck applies to hold it in the neck)
8. I weigh my cases and sort by weight in 2 gram increments (if you looked in my empty brass cans you'll find many brands/headstamps divided by weight - if the cases are resized with the die set up the same way, trimmed to the same length, the necks turned to the same wall thickness then when you sort them by weight what you have is consistent, from case to case, internal volume - if the internal volume is the same then the pressure will be the same as long as the powder load is the same. Consistent pressure leads to consistent velocity which leads to tighter groups). I only do the neck turning, case weighing thing the first time and then I keep the "lots" of sorted brass together (the same way some folks do by headstamp and year).
9. Then I start load development as I now have cases as consistent as my bullets and primers.
This road never ends. It gets ahold of you and doesn't let go. It takes a lot of time and effort to "build and test" the loads in your rifle.
You can decide how much trouble you want to go through. Each of us determines what works for us and these are just some ideas I've found work for me. Why do I believe in the above? Busting gallon milk jugs (fill'em with water first) at 500 yds with my old 03A4 with my reloads. Putting 4 or 5 bullets in the head of GI pop up at 600 yds. with my M1A (yeah I wish it was all 5 but it wasn't and this particular load was very accurate but wrong for an M1A and resulted in cracking the operating rod twice before I read that IMR4350 was wrong for M1A's).
You need good quality bullets as well. Hornady's were good but my best results were with Sierra's, the matchking 180 grn. bullets. There are other choices today, my reloading/shooting was done over 20 years ago. But I'm going to get back into it. I've already started.
Good luck.
Good points, M1A4ME.
One thing I would like to contribute, if I may:
You get what you pay for, in ammo and in all things.
And part of the cost is the elbow grease you put into your reloading.
You can go out and buy Lapua brass, expensive match grade primers, the most raved about powder on the market, Sierra 175gr Matchking bullets and all the pretty blue, green or other colored reloading gear on the planet. If you assemble it in a half-a$$ed manner, you'll get half-assed ammo. I'll probably be outshooting you with carefully prepared ammo consisting of 3x shot brass, CCI primers, surplus powder and 150gr pulled M1 bullets.
Another angle to consider: how much is your barrel worth to you? It'll cost you upwards of $300 to rebarrel your favorite rifle, oftentimes much more depending on the quality of the barrel you purchase and the reputation of the smith you hire. How many rounds will you get out of a barrel? 5000 rounds is about "it" for a match rifle, but we're worried about battle rifle life expectancy. Maybe about 10-15,000 rounds or so. Do you want to waste that barrel shooting the worst bullets available through it?
Accuracy costs. If you're happy with 2MOA accuracy, you can achieve it via some elbow grease and inexpensive components. And your barrel will do so for at least 10,000 rounds probably, unless it is a fire-belching .300 Remington Ultra Magnum or some other cartridge generating over 60KPSI. If you want 0.5MOA accuracy, you need to be buying some premium match bullets, sorting brass by weight and thickness, uniforming flash holes, trickle-charging your powder charges, and individually measuring your seated bullet OAL (along with any number of other steps you may find to be beneficial). Doesn't matter how "good" your bullet is, if you aren't paying attention to the assembly.
But the most expensive (and therefore valuable) component in your reloading process is your own attention to detail. Without it, your precision brass and bullets are just lumps of metal to be smashed together in any old haphazzard method.
That being said ;), I load the bulk of my rifle ammo to a powder accuracy of +/- 0.2gr, use pulled M1 150gr bullets, and aim for an average COAL of 2.775". This stuff tends to give me about 3MOA, and I am happy with it in its intended purpose. I use 168gr Hornady HPBT match bullets for paper punching accuracy, and I get about 1.25MOA out of it after all my particular stages of brass prep that I am willing to do. My hunting ammo, using 165gr Hornady SPBT bullets, gets similar treatment and gives me about 1.5MOA accuracy.
My steps for ammo I desire to be peak accuracy:
1. Start with 100 new brass... I favor Remington, but I can do the same thing with Winchester or Federal too.
2. Deburr the flash hole, uniform the primer pocket depth
3. Resize using full length sizing die of choice
4. Trim to length
5. Chamfer the case mouth
6. Tumble to remove brass filings
7. Soak in water to remove dust from tumbling
8. Dry on paper towel for a day
9. Weigh each case, find a median weight in the batch and select the 49 closest cases to the median weight. The remaining 50 cases of varying weight are to be used for target practice with less-than-premium bullets.
10. Prime the cases using preferred primer
11. If my preferred powder charge is 42.5gr of IMR4895, then I throw an estimated charge of 42.0gr +/- 0.2gr into each case, and trickle charge the remainder into the case.
12. Weigh all 100 bullets from the box I purchased, find a batch of 50 that all match in weight. I typically get 60-70 that are identical to the 0.1gr increment that my digital scale reads to, in a box of Hornady 168gr HPBT match bullets or 165gr SPBT hunting bullets.
13. Seat the bullet, without any crimp. I check every bullet for length for the first 5, then one bullet every five for consistency. The match bullets have no cannelure, but the hunting bullets do... I crimp these in a separate step using a Lee factory crimp die, very lightly.
I'm in agreement with both of you, but I have to think about the
water treatment if it isn't black powder or corrosive priming envolved.
Any left over moisture or oil can make you wonder how many others may
not fire. To keep dust down, I have cut up a sheet of that fabric
conditioner that is used in clothes dryers. Picks up the dust and gets
discarded after a half a dozen loads. For popping out the carbon in
the primer pockets a small screw driver slightly smaller than primer pocket
diameter works fast without disturbing the brass in the pocket ;D