Quote Originally Posted by Merc View Post
The PPU .303 brass has held up really well through 10 or more reloads without head separation or overly enlarged primer pockets. It has a slightly smaller powder charge than the .30-06 which probably helps. By only neck-sizing the cases, I noticed the walls of the cases have expanded to fit the generous No. 4 Mk 1* chamber to the point where they've become difficult to chamber and eject. Have you noticed this? I've not seen this happen with the .30-06 cartridges.
If you neck size the body will expand to the point it needs full length resized every so often. I full length everything in 303 and 30-06 because I want to be able to shoot it out of all my L.Es and American Mil Surps, so no direct advise. On others I have singles (example 1918 Carl Gustav 6.5 X 55) I full length resize every fourth firing. Others might be able to tell you what they are doing in 303 and 30-06. A chamber gauge could be used but in military 303 bores I've been told it's hit or miss due to bore size differences. Good luck.