Those of you who are already handloaders will note that a lot of equipment is missing from this list. That gear is not necessary for basic reloading. I have added the calipers so that the inexperienced will recognize the need to trim cases that are too long. If your rifle cases have only been fired once, they will probably not be dangerously long. I wouldn't bet my face on it though, and that's why they are in the list. I have found factory brass that was too long after one firing, it would not have projected into the rifling but then I don't know what kind of rifle the reader is using, and I don't want to feel responsible for someone's misfortune.
Don't assume that because the cases are new that they are OK to use. Inspect for any irregularities (e.g., splits, bulges, or enlarged primer pockets). Separate your cases by headstamp, number of times fired, and if you know the lot numbers of the cases, by lot.
Clean and lubricate the case with a lightly oiled cloth or resizing lube. Do not use water to clean the brass, just wipe it off good, blow it out, and lubricate. If you are using bottle necked rifle cases, take care not to get lube on the shoulder. The lubricant is necessary to keep your case from sticking in the resizing die.
After firing, the case neck is too big to hold a bullet firmly and the case itself may be too large to chamber properly. For reliable feeding under adverse conditions, you want a round that will slide quickly into the chamber. Auto-loading rifles can be finicky, and when on foot against dangerous game, you want reliable feeding. (If you have spent thousands on a hunting rig, i.e. 4WD, 4-wheeler, camouflage clothes, guns, leases, club memberships, etc., it would be a shame to miss the big one because your rifle "jammed.") Leave neck only resizing for the target shooters. In advanced topics.
By the way, most standard resizing dies also decap the primers in the same step. You know what really pisses me off? Having two shell holders, one for the die and one for priming. If you buy a lot of equipment, consider this, it will save you a lot of aggravation. Buy a priming tool that uses the same shell holder as your press uses. I wish all manufacturers would standardize this little $1.79 item. I STILL use separate shell holders and it really gripes my ass.
Follow the die manufacturer's instructions for adjusting the die. The "old country boy" method is to run it down into the press until you can just fit a nickel between the shell holder and the die when the ram is all the way up. This will usually give VERY full length resized cartridges.
Make sure the primer is seated firmly, all of the way in and evenly around its edges. If it's not all of the way in it will move when struck with the firing pin, resulting in a misfire, or at best, inconsistent shot groups.
Always use a powder scale. I have loaded small pistol cases by volume after careful trimming. It works better when using true "ball" powder because the stacking coefficient is consistent. A large rifle case should only be loaded by volume by very experienced loaders, and then, only in emergency situations (i.e. you are miles behind enemy lines, knee deep in hand grenade pins, and in danger of being captured by the enemy)! For that matter, go ahead and load one up to be placed on top when capture is imminent, it will give the little bastard who fires it something else to remember you by! Just make sure you mark it clearly AND put it in a pocket.
Start with a light load but do not go below those recommended in reloading data manuals. Some cartridges can behave unpredictably (dangerously) when loaded too light. Use your funnel to pour all of the measured powder into the case.
The "old country boy" method is to make your cartridge as long as a factory round is. Make sure the factory round uses the same style bullet (round nose, pointed, etc.) A better way (still "old country boy" though) is to take a clean shiny bullet and seat it WAY too long. Make sure the bullet is tight in the case so it won't stick into the rifling. Now chamber the round and close the bolt gently. Extract the round and you should see where the rifling seated the bullet for you (evidenced by rifling marks on the ogive of the bullet). Now back the bullet off just a hair (.003 - .005"). Next, test your round to make sure it fits into the magazine! Note many rifles will have shorter magazines that do not allow bullets of optimum length.
Are for all handgun bullets and bullets meant to be fired from tubular magazines. If your rifle is a bolt action, ignore the cannelure if present. You'll find these little oddities on some 180 gr. round nose .308 cal and some others. If you want to crimp (handgun shooters etc.) set up your seating die in accordance with the instructions.