I have reloaded for a while now, but until recently I haven't had the good fortune to work with brand new brass.
What (if any) prep work is needed or do I just tumble to remove any mfg. oils, neck size, load and shoot? Specifically Lapua in 300 Win Mag and Norma in .257 Wby Mag.
What I usually do for my brass (once fired) the first time that I reload it is visually check the brass for any defects, trim to minimum length, deburr the flash hole, uniform the primer pocket and neck size only. This is for brass that has been fired in my gun only, and I don't swap brass from one gun to another.
I'm starting to develope loads for my buddy's 300 Win Mag, and while he gave me some empty cases that he's fired (60 Federal, 50 Remington and about 20 Winchester) I ordered 100 new Lapua cases to make things a bit more consistent (plus I was advised by another member that it would be easier to get a great load by using good uniform brass)
I thought I'd use the Lapua brass for the longer range loads and the Federal/Remington for the <200 Yd. whitetail loads.
Inspect cases for defects. Any brand can have them.
Run all cases into a sizer die to uniform the necks. Trim all cases to same length and chamfer. On my RCBS case prep station, I use regular bronze brushes for bore scrubbing and put one in the prep station. I scrub the inside of the necks for about 10 seconds each with the rotating brush to get out any factory coating or debris. Deburr flash-hole, not really necessary with Lapua. If you use an expander when sizing, then I would recommend you scrub inside case neck as step 1. The only time I use one is if the case necks are slightly dented. Then I size twice. Once with expander to uniform outside and inside, then again without expander. Then trim.
Run all new cases on concentricity gauge and separate into batches based on apparent run-out. Up to .002 is tier 1, .003-.004 is tier 2. Any more than that and they are for play, fouling, barrel break-in, etc. Granted, you will have some aberrant findings due to the cases being unfired and asymmetric case wall thickness anyway, so I do double check all after first firing and re-segregate.
Norma and Lapua brass I do not mess with primer pocket. Lesser brass, I will, if I'm not too lazy.
You brought up two things that I've been meaning to acquire - the case prep station and the concentricity gauge. There are a few concentricity gauges out there, are there any that are heads and shoulders above the rest?
I need to purchase both of them pretty durn quickly!
I didn't have a set of dies for the 300, so I purchased a RCBS set, plus the lee collet sizer. They should be delivered early this week.
I got mine from Sinclair. Check out their website and you'll find all the info you need. Be sure to check your finished loaded ammo for concentricity also.
Even when you do your very best loading technique, you can still have variances with runout. Take the ammo with greater than .002 runout (if you get any) and put them at the "back of the line" to use. When I check each one, those that have no runout to .001 get to be in the front of my ammo box. Then the ones that are .002, and so on.
Depending on which rifle I'm loading for, I've had to load up 100 rounds just to get 50 good ones and 25 excellent ones. But that is not always the case.
I use to seat a bullet, just barely....just enough to where the case mouth grabs it, then back the case out of the die, rotate about 1/3, seat a little deeper, then rotate 1/3 then fully seat the bullet.
Now, I do the same thing but with a lot more steps by BARELY turning the brass and BARELY seating the bullet with each pass. I have found that even though this is quite a pain in the *****, my concentricity has greatly improved where greater than 50% of my handloads are now .001 or less. Maybe that is great, maybe I suck, I don't know.
But, mark my words, ime the more concentric the ammo, the better it is.