Many today are handloaders. Some are just reloaders, they reload the fired brass from their own rifles and handguns then shoot it again and again. The folks usually don't consider their handloads to be the best ammo available for various reasons and usually use factory loaded ammo when hunting or for serious competition.
A true handloader hand crafts ammo to their individual gun and generally consider it to be the very best available, for their guns anyway. Usually it is just that. Handloaded ammo can be highest quality when loaded with reasonable care and taylored to an individual gun, and will likely be the best performer when correct components are selected.
Part of this process is good record keeping. We must know what works and how well it works. This is true not only for accuracy but field performance of various bullet styles and other factors such as fitting the magazine and ease of cycling in the guns action are also important.
Record keeping should include the guns description with barrel length and possibly scope or type of sights and the sight setting for this load. Such as 3 clicks up for 200 yard zero from a standard sight setting or setting for another load.
I keep this data on the heading of a one page form and on this form I have space for ten different loads. The header of the page contains the bullet weight and type and the case brand, trim length, times fired. The load columns have powder type and charge weight as well as a place for primer, velocity, extreme spread and standard deviation of velocity.
All loads on this sheet will be with the same brass and bullet. With this bullet I will list the contact seating depth (where the bullet meets the rifling) and also the seating depth of these loads. Generally the same primer will be used and the same powder is usually used for five different charge weights. Should the primer be changed from say, Federal-215 magnum rifle primer to CCI-250 magnum large rifle, the second five loads will be duplicate powder charges of the first five with only the primer changed. This does two things for me. Changes of components are held to a minimum and when changes are made there is adequate testing to verify results. Each different load will be loaded in quantities of five for the initial testing. Putting ten loads on one sheet and a total of fifty rounds will use up a box of rifle bullets quickly.
I usually load three different calibers to take to the range, three different guns with at least five different loads (25 rounds) for each gun. The makes for shooting five through the chronograph with one gun then allows for ample cooling time between shoots as I go to the next gun.
After these shooting sessions I will find the most stable load, the one with the lowest SD and velocity range I want (hunting loads get hunting bullets and hunting velocity). Then I will test for accuracy and if need be vary the seating depth of the one selected bullet to better grouping. Here again accuracy commensurate with the purpose of the cartridge/load/animal. Meaning I don't need .5 MOA from a 416 Remington for buffalo or brown bear hunting. Likely 2 MOA would do the job at 80 yards. In this situation reliable feeding and positive ignition with the best possible terminal performance of the bullet are the more important criteria.
My handloaders log tells the story. All the load data. The actual velocity from my rifle. The good loads and the bad, for what ever reason. For future reference, I will know the best load with any given bullet, the correct seating depth for that bullet as well as the powder/charge weight/ primer, to recreate that particular load for my rifle. A copy of my log will be posted as soon as I find how to run the scanner without catching the cat on fire this time. What a smell!!