Your new brass should be full length resized for the first firing just to iron out any imperfections. If you come across any brass which is seriously flawed it should be culled. This would include split necks, flattened shoulders etc, and does not mean little dents or scrapes which commonly occur during shipping or packaging.
If you are just starting to reload, your loading tools are probably fairly basic , which is fine, but if you don't have a flash hole deburring tool, a drill bit, that will just fit in the neck, and turned in your fingers will cut off any burrs left from punching the flash hole.
After the first firing the brass case will be a perfect match of your chamber. From this point on you can neck size, although I find it useful to set back the shoulder from time to time to ease chambering. My own rule of thumb is to full length resize my hunting ammo, because I want it to function flawlessly through the rifle. I usually crimp my hunting ammo provided the bullet has a cannular. This does two things, first it makes the bullet pull weight more uniform from round to round, secondly it prevents the bullet back from being pushed deeper into the case when the round is slammed into the front of the magazine box during recoil. This might not be an issue with your rifle, it's just something I've got in the habit of doing.
I work up my target rifle loads with the bullet pushed firmly into the lands. This does two things as well, it uniforms the bullet pull weight, and it centers the bullet in the bore. If the best accuracy is with the bullet slightly off the lands, I don't have to adjust the load when I'm finding the sweet spot, because maximum pressure occurs when the bullet is in contact with the lands.
If you start loading cast bullets, it will be necessary to slightly bell the case mouth to accept the bullet. An "M" die can be purchased, but you can use a slightly larger bullet tapped with a nylon mallet to do the same thing, and after a few tried your results will be quite uniform. If you are loading a .30 caliber cartridge a .35 caliber bullet would work fine.
Check your brass after each firing, if it's lengthened beyond the parameters set out in your loading manual it will need to be trimmed. Some reloaders trim the brass slightly shorter than the "trim to" length in the manuals so that they won't have to worry about trimming a second time. If the rounds are loaded to the same OAL, this presents not pressure issues, although there is less neck to grip the bullet. The rule of thumb is a minimum of one caliber of bullet shank contacting the case neck.
When priming, if the primers seat into a case with no effort - the priming tool just hits the bottome with no resistance - the case must be discarded. This usually does not happen for a number of reloads.
I hope this helps.
