Futo,
Good points.
FYI, I have shot the 40 loaded long for about 2 years in IPSC. The difference in my situation is I shoot a barrel chambered to 40 headspace dimensions. I have the rifling leade reamed to accomodate the longer bullet length
At 10mm lengths, even as short as 1.200, the pressure in a 40 is greatly reduced. However i still think a supported chamber is mandatory for the 40.
Controlled round feeding has nothing to do with headspace.
