Here is a link to a folder of pictures of a 25 caliber nail gun charge round that I started to develop. The bullet is 223". The case is a 25 Caliber nail gun (just a touch bigger diameter than a 22WMR. Some old 22WMR chambers will accept these charges. And don't let it fool you...this little charge has MORE power than a 22lr. After looking at these pics. I see that one step of the process has been omitted. The little piece of wood with the charge in was put in a drill press (not running) with a pointed tool (like a dead center for a lathe) that I pushed down on to the very center of the crimp to open it enough to get the post of the bullet into. Then the bullet was forced into the opening. The pressure on the angle of the crimp forced it a bit closed ...crimping on to the post. I never tried them...I have a barrel that I needed to ream a chamber out to accept them then make a gun for the barrel.
https://www.dropbox.com/sh/w2advszii...dFfQBpmna?dl=0