I have two co-ax presses, they get used all the time.
The co-ax is fast to swap out dies and fast grab a case with the jaws close. Other presses, these days, have come up with other fast die swap outs, but the co-ax jaws still offer unique advantages. Also the leverage of the co-ax is very good.
Here is one minute of my depriming cases with a co-ax using one hand:
http://www.youtube.com/watch?v=vkT_s4jerLQVery observant watchers of my video might figure out one modification to that press, as the 37) Shellholder jaw housing is clearanced for the 44) Jaw opening screw (long) to pass through full diameter.
I have made my own:
37) Shell holder jaw housing
20) Button head screw
1231) "S" lower shell holder jaws
46) Wear plate
13) Handle
I was impressed with Clarance Purdie's 1969 patent.
http://www.freepatentsonline.com/3440923.pdfI think that it was built by Gopher shooting supply, then Bonanza, then Forster, and now is off patent and still being built by Forster.
The first mod I did was to fasten the wear plate to the shell holder jaw housing. I had two sets of housings, wear plates, jaws, and springs. This made for a fast jaw size swap.
Then I went back and tried harder.
I was only able to improve on two parts:
37) Shell holder jaw housing
20) Button head screw.
I could make the 37) shell holder Jaw housing:
a) stronger so it will not bend when a case gets stuck
b) clearanced for the jaw opening screw
c) semi circular chamfers on the bottom, not the top, correct that error.
d) capture the 39) jaw pressure springs so they don't fly across the room
e) clearanced for a better screw than a 29) button head
f) milled from 1010 steel, not cast steel
I could make the button head screw:
a) From a knurled head screw, so I can screw it in with my fingers
b) pointed on the end so it lines up the holes in the 37) shell jaw holder housing, 46) wear plate, and 45) guide block casting.
I wanted to be able to change jaw sized in a few seconds while blind folded. I made a dozen of these set ups and sold them on line. I gave my sketches to a CNC guy who sells now.
It seems some guy on LONG RANGE HUNTING who owned a CNC machine shop made much the same changes as me 10 years earlier.
I have told Forster co owner Bob Huck about my changes. He is one smart guy. If the changes were cost effective, he would do it.