Thread: Excessive head spacing 7mm RM - can it still be used

Greetings Again Vandros,
I just realised that I did not specifically address your question of will the excess headspace cause ruptures. Unfortunately the answer is I don't know. You could carefully inspect the outside of the case about 6mm up from the base to see if there is a bright line part or all the way round the case if so these should not be fired. The other way is to pull the projectiles and save the components followed by checking with the bent wire as above. I see you live in Auckland so see if you can find an older handloader to help you with this. A whole bucket full of posts is nowhere as useful as 10 minutes of one to one instruction.
One of the options for setting headspace accurately is the Redding Competition Shell Holder kits. From your measurements these may not have the adjustment range needed (at + .010 inches) in your case. I ran into this problem recently with my 6.5x55 rifles. Two sets of dies including some new Redding dies both set back the shoulder excessively. My t3 has a tight chamber with fired Lapua cases barely longer to the shoulder after firing than new. Even the + 0.10 shellholder sets the shoulder back a little more than I would like for this rifle and way too much for my M38 and a friends M77. It seems that the US diemakers are working to a shorter headspace dimension than the Scandinavians who invented the round in the first place. Unfortunately this type of arrogance is far from rare in the US.
Regards Grandpamac.