ARLover, working up loads or figuring out which commercial ammunition your rifle likes best is an important step but realize that there are two systems at play. First, what is the rifle capable of and second, what are you capable of? If you can remove yourself as much as possible from the first measurement (bench, sand bags front and rear etc) you'll know what your rifle is capable of. Don't underestimate the psychological importance of this. Once you have that figured out, you can then work on the second issue which is you. Shooting small groups is one thing, shooting small groups in the center of the target is another issue all together. I've seen/met many shooters that shoot small groups but the group isn't in the X-ring. Why is that?
It's more important to put your shots where you want them rather than getting small groups where you don't, but that's a whole new thread.
Personally, I work up loads following the OCW method of shooting anywhere from 5 to 8 different loads (five rounds of each) in a round-robin system i.e. one shot from each load on separate targets. Then I fire a second shot from each load at each of the targets and so on until all loads have been shot. This approach helps to remove some of the shooter fatigue, changing environmental conditions and changing rifle conditions from the data. As for fouling shots, I shoot a group of five rounds at the start of the session. I generally choose a load that I think is a good one to see what happens as the barrel heats up and fouls. It helps if you record the position of each shot so that you can track the changes. I also will tend to shoot the same loads over a few weekends to get a better average performance of each load. A chronograph can help too since low ES and SD numbers often coincide with small groups. I have a log sheet and record the position of each hit on each target as I shoot. If you feel that you flinched, pulled the trigger at the wrong time, the wind suddenly picked up, the shot didn't feel right (more/less recoil) etc. record that information since it'll help you to interpret the results.
The time between shots will depend on the caliber, velocity, the type of barrel (dimensions), weather etc. If the barrel is just somewhat warm then I shoot. I don't wait for it to be stone cold. If the barrel is hot, a chambered round can heat up enough to raise the internal pressure and therefore increase the velocity. This shouldn't be a big issue at a range shooting one round every three to five minutes, but in a match shooting one round every 5 seconds or even one round every minute, this can affect velocity.
As for shooting techniques, consistency is the name of the game. Whatever system you choose, stick to it and don't keep second guessing yourself ... that will just lead to frustration. I breath out slowly and time my trigger pull to the period when almost all of the air has been expelled from my lungs. Put your fingers to your jugular and feel your pulse as you breath in/out/pause etc. You'll find a "window" where your pulse slows and that's a good time to be pulling the trigger.
Good luck and practice is EVERYTHING!!!
