[madcratebuilder]

I belive that this is the basis for that claim. The k11 chamber is dimensionally smaller than that of the k31. Most dies are set to size brass so that it will fit either chamber. I believe that Redding and now Hornady have dies which are calibrated for the k31 chamber and that brass sized in those dies won't fit into the k11 chamber. In that regard, the brass is resized less.

This is an excerp from a post by Parashooter illustrating some of the dimensional differences:

Redding info on Midway

"Note: Intended for the K31 rifle. Dies for earlier 1911 model rifles may be obtained by contacting Redding, the dies are a custom-order item."

The other die manufacturers do not have this. Apparently Redding thinks there is a difference between the two cases???