i've seen several wildcats out there that are "ackley improved".  i understand that these are just commercial rounds that have been modified to a 40 degree taper (and in some instances) the case wall straightened.  

my qusetion, if you were to get a 6.5x55 or .260 and rechamber for the ackley improved version, can old 6.5x55 or 260 ammo be fired safely in the new ackley improved rifles?  also, is this what is refered tio as "fire forming" the case?  

thanks, sloth  

Yes.[:D]

We have two Ackley improved rifles in my family (30-06 AI and 243 Winch AI) and have had great success with both rifles. Yes, you can safely shoot standard 30-06 ammo in the 30-06 AI chamber. That is the main way in developing brass. Also adds a little versatility for example if you are in Alaska with your 30-06 AI and you forgot your handloads, you can still hunt sucessfully with standard 30-06 rounds from local stores. Improving rounds (THIS IS NOT WILDCATTING) offers the shooter with longer-lived brass and about 200 fps increase in all bullet weights over the standard. Wildcatting requires more work where a handloader is actually "shortening, necking-up or down" or some other step before fire-forming.

Karl