I started turning necks about 20 years ago, using the data from German Salazar, using old cases to practice.
Started with K&M tools and they are still my favorite. Have about 20 cutters set for each rifle. You'll need the heat shrink to hold cutters and their neck micrometer. Good Luck.
It's not a big deal if you have the right tools. I turn brass for all my rifles plus my son's rifles and I rather enjoy it. All our rifles have custom chambers, so it's important to have proper neck clearance and neck wall consistency.
We go through a lot of brass, but it's something to do in...
Can you take some pictures of some resized brass you have tried to chamber?
Sounds like over-pressure, what bullet and what powder & charge are you using? Also some measurements right above the web on fired vs. new brass.
Yes, it has a taper. I use K&M mandrels and use Imperial Wax on a Q-Tip to lightly lube inside the neck. You'll also need the threaded plug to hold the mandrel. Then adjust the mandrel plug in your press so that it sizes the full neck but does not hit the bottom of case. Very simple to use.
Yes, 2 grains will usually work, so 1 grain sort will be better.
I just sorted 200 pieces of Norma brass for my 264wm. I only had 1.8 gr difference. I'll sacrifice a case on the middle weight and call it good.
Sort your brass by headstamp, then sort by weight by 2 gr. +/- so you get consistent annealing.
Once your sorts are made, you'll have to sacrifice a case from each sort using the Aztec mode. Then keep them sorted thru their life.
It's far simpler to start with new batches of quality brass...