For strictley punching paper, the Bergers, JLK's or SMK's will probably be the best choice, which ever shoots best in your rifle. 180 E-Tips actually seem to be doing as well as the Bergers in mine. AB's show good promise in mine but ran out before I could get much in the way of accuracy results. Waiting for more to come in.
You'll get different opinions on break-in. I will always break-in a barrel. It has reduced fouling in the barrels I've done it in. My Senderos were used. The 300 RUM only had 20 rounds through it but it is a fouler. I think it may have expeienced some corrosion/pitting - it was about 3 years old. Don't know how many rounds the 25-06 had, but the first time I cleaned it, it took 5 days to get all the copper out. 4 Days of soaking with Wipeout, 4-8 hrs per soaking. I had it borescoped and it was firecracked from the throat to the muzzle. The Smith didn't know how I could hit anything with it. It's still shooting well though.
I thoroughly cleaned both completely free of copper and broke them in using a product called juice which is supposed to lay down a protective layer in the bore that can not be removed other than very high temps. It's also supposed to increase velocity. I cleaned all copper out between each shot of the 300 and applied Gun Juice before each shot for a little more than 20 rounds. For the 26-06 I cleaned some copper out (not all) for the first 6 or 7 rounds and then most copper after that. The idea was to "seal" copper in the cracks in the bore with the Gun Juice. Did the break in for a total of probably about 30 rounds in it. Very, very time consuming and tedious with these bores which needed a lot of attention. It reduced the fouling in each. The 25-06 can be cleaned by Bore Tech Eliminator in a couple of hours with 20-30 min soakings followed by one or two Wipeout soakings. The 300 is a little easier but it's still a fouler. They both seem to last about 60-70 rounds before accuracy starts falling off. The last I cleaned the 300 it took about 5 fowler rounds to settle it in. The 25-06 is still shooting very well after about 250 rounds after being borescoped.
IMO, a good break-in should work out some or most of the roughness in a factory barrel.
BTW, I'm glad I'm starting with a factory barrel. It's been a big learning curve and by the time I burn this one and get a custom match barrel, I might have a clue what I'm doing