Answers to your questions Silvershade:
1. 30-06: still one of the best all-around cartridges on the planet. I have nearly all the new-fangled rigs to come out in the last ten years, you know, just because...but I still have a wonderful, beautiful Sauer 90 Lux (circa 1988) in 30-06 and a new custom rifle in '06 that just got this week that shot .259" group with 165 gr Sierra factory ammo first trip to the range with no break in nor other voodoo. BTW, if you get into reloading, I use 165 Sierra Tipped Game King bullet or Nosler Accubond, 57 grs. IMR 4350, CCI BR-2 primer and LaPua brass. I get 2800+ in three different rifles and while they don't all perform the same, they are all MOA(ish) or less shooters. I've prolly shot 1000 rounds of everything in test loads and keep coming back to that load. Pretty much any brand 4350 will work you just have to adjust the charge and RL-17is very similar in performance--maybe a tad faster in some rigs...I've gotten a 50-70 fps faster with that but in select rifles.
2. Rifle Break-in: Yeah, I do it because I'm gonna burn some rounds to get zeroed, meet the rifle and get settled in and because it's fun and it channels my inner Sheldon Cooper.
I use the method suggested by Fierce Firearms since I have three of them and its pretty straight forward:
a. shoot one round and clean the bore...do this for the first five (5) rounds.
b. shoot five rounds and clean the bore...do this for the three sets of five following the single shots--(3-5 round groups after singles) in total. i.e. It should take a box of twenty (20) cartridges to complete this regimen-five singles and three five shot groups.
c. Clean the bore, run a dry patch, an oil patch and one more dry patch. Store it. Shoot one fouler round before hunting or subsequent range work.
You might also shake a chicken leg over the barrel after completing each phase while burning some rose and patchouli incense--no I'm just kidding about the last part...or am I?
That said, I recently purchased a Browing X-Bolt White Gold Medallion rifle off the shelf in 6.5 PRC. Leopold VX6HD 3-18X50 CD scope, Warne rings. I didn't really have a lot of time on the range and wanted to take it hunting on my son's ranch that afternoon. Took 4 shots to zero the rifle--2 @ 25yds and 2 @ 100. Then shot a five shot group using Hornady Factory "Superfromance"143 ELD-X ammo that was right on 1 MOA or a bit more...meh. Went hunting with 9 shots down the pipe intending to return to the bench in a few days to "do all the stuff". 10th round out of the rifle was a DRT one shot kill (125 yds) on a big old management 8pt whitetail (big, old deer, rack in decline). I went back to range two days later with a stack of various factory ammo to cheat and narrow down bullet type for a reloading starting point...I'm lazy like that
. The first group I shot was Nosler Trophy ammo with 142 gr Nosler ABLR and it turned in a five shot bug hole about .375". I stopped there and did not perform a "break-in" nor work up a load since that one was turning in 2800 FPS...I called that good enough with the .660 G-1 BC. Sent the data into Leopold for custom turrets. So, two arguments, two sides of the spectrum from the same guy
! I must confess--I do like the break-in ritual...more shooting=more fun.