Quote Originally Posted by Ro-bert View Post
Is almost no difference to see with the naked eye on the fired brass. But i could observe on cartridges without O-Ring was several times primer a bit pushed out of pocket. So - i think - with the O-Ring method could my SMLE cases live longer. What do you think - is it reasonable to use O-Rings also on my No4?
The o-rings of either monofilament or rubber seem to negate any headspace dramas if used on the first firing. Not needed afterwards if cases are resized only to the point where they will JUST chamber without undue resistance. However, these rounds MUST be only used in the rifle from which they were fired.