Thought I'd move this over from the S&S forum for further discussion and examples.
I've both a Paco Kelly Accurizer and the Neal Waltz die for 18 +/- years and use one or the other on most all my 22LR ammunition exception being the high end 22LR Match I use for 100 yard BR competition. Groups with regular 22LR do improve most of the time. CCI Blazer Is one that is really improved both for accuracy and when HP'd for hunting. The increased terminal ballistics of the larger HP made with both tools and the "Nasty Nose" with the Accurizer can be readily seen and heard.
With the Waltz die when I find the correct amount of swaging and/or HPing I measure the OAL length of the die bottom to top of adjustment stem and record that measurement. Thus, when more of that particular 22LR ammunition is had I simply adjust the die to that OAL and it is good to go w/o any further testing.
With the Paco Kelly Accurizer I found long ago that whacking with a mallet wasn't very consistent. An Arbor press works much better but the one I have doesn't have a "stop" so consistency of the swage, while better than whacking, still wasn't what i wanted. I found a use as an arbor press for an old Craftsman drill press stand [hand drill attached to it, but the hand drill gave up the ghost many years ago] worked much better. With the Accurizer I measure the AOL of the swaged rounds and record the OAL of the most accurate for a particular 22LR brand/type of 22LR cartridges. The drill depth stop of the press can easily be adjusted to reproduce that OAL with a new batch of the same cartridges with excellent results.
Here is the results of a 100 yard test of Winchester "White Box" match 22LR. Rifle used was my Stock Remington M37 {made in '51/'52] with a Weaver T36 scope on it. The inner ring is 1". You can see the improved accuracy as the 22LR cartridge is swaged in various amounts. Still, it does not equal the accuracy level of OOB [Out OF Box] Lapua Midas+ [ottom target].