Depends on how many you think you will ever do. I have the RCBS primer pocket swage for doing this. It basically is used in your press and you simply put the brass on the ram that has the pocket swage and run it into the die. It swages the sharp shoulder to a nice round one like on factory brass. If you only have a few to do, you can do it with any deburring tool. Just knock off the sharp corner. Some folks do it with a drill but I have found that they usually take too much off. The RCBS tool is good for small and large pockets and can also be used to correctly size pockets that are a little loose or too tight.
As of right now I only have 100. But if I get the chance I will get some more.
I need some for full loads for my 2A1's. I'll be using commercial brass for starting loads.
I am getting 5 firings with factory ammo with the starting loads neck sizing before having to FL size.
The heaver loads seem to swell the cases a little too much with factory/commercial brass. :---
I have used the RCBS swager tool (the one used on a single-stage press), with poor results. I also sometimes use the RCBS case prep station tool, which works OK but is fairly slow. Usually when I remove crimps, I'm dealing with several thousand cases and I set up my hand drill with a Lee or RCBS chamfer/swager tool. There is a holder sold for it that makes it simple as a drill bit to secure in the drill. I do the whole operation with the drill setting at the bottom of an empty corregated board box to trap all of the brass filings. The only issue with that method is that it's very easy to take out too much metal which ruins the case. It's an acquired feel, though, and I can move a lot of cases very rapidly.
I'll chime in with the rest here. I have the RCBS Press Mounted Swager Tool and it is poor at best, terribly slow in fact. I also have and use the RCBS Case Prep Center, but it's not much good for removing primer pocket crimps. I just bought the Dillon Super Swage 600, and it is the only way to go. I swaged out over 3,000 cases last week in just a few hours, and with very little effort. It's worth every penny. Next I'm going to purchase a Giraud Automatic Case Trimmer. They're expensive, but quality tools that work well usually are. Again, the automatic case trimmers offered by Lyman and RCBS are slow, and don't chamfer the inside and outside of the case like the Giraud does. I learned long ago that it pays to part with the added money up front, rather than suffer with poorly designed tools that take forever to do what amounts to a poorer job. To me there is nothing more frustrating than that. Here is a clip of the Giraud Trimmer in action. 10 cases a minute at a relaxed pace. Bill T.