How dangerous is this condition?Very.
I had this happen on a common or garden box lock of Belgian manufacture. There were thousands of this model imported in the 50s and 60s; I got mine from Wm Powell in Birmingham in '64.
The
cause was an imperfectly formed striker nose that wasn't hemispherical, but a bit more like a truncated cone. It penetrated the cap, and in consequence the whole of the action was pressurised.
The
effect was to detach a piece of the of the woodwork immediately behind the right side of the standing breech, and blow it just passed my right eye. The piece was about two and a half inches long and roughly the thickness of a pencil, maybe a bit fatter.
Being a right hander it did no more than soil my underpants (we found it about fifteen feet behind the shooting stand at the foot of a stone wall.) I was being coached by Joe Neville at the time, and he was standing behind me, but thank God it missed him too. A lefty shooter would have without doubt lost an eye.
If you've got away with it once, say a thank you to St Patrick, and
NEVER shoot it again before the fault is identified and remediated.
KYJ posted
A single pierced primer is not that big of a deal
Sorry Jon but given my experience you'll see why I vehemently disagree.
Eug