I had an old one I bought in 1976 and I didn't use it much because it "pushed" brass into the primer pocket because it was so roughly made.
So I bought a new one a few months back and it ruined a lot of primer pockets because the diameter of the swager was too large.
Below the older unit is on the left and the new unit is on the right, both are for small primer pockets. The new unit is larger on the tip than the diameter of the primer pocket, meaning I ended up with oversized primer pockets on every case I swaged.
Below the new units diameter was larger than the "normal" diameter of the primer pocket. The swaging is to be done near the base of the unit and "NOT" the tip.
Do yourself a favor and go buy the Dillon Super swager and be done with it, you will be money ahead in the long run and have top of the line equipment that does the best job.
If you only do a few cases then get the RCBS reamer below made for the case prep station, it is tapered and only removes the crimp and bevels the primer pocket mouth. If you have to do a lot of cases your fingers will get very sore holding the cases and you will wish you had the Dillon unit.
Did I tell you I'm saving up for the Dillon Super swager and I'm tired of having fingers so sore you can't pick your own nose.
I had three five gallon buckets of .223/5.56 brass to do and decided to be cheap and do it the hard way.