@mucko. Glad it was no worse mate. Couple of questions. Forgive me please if you have considered these points, which is probable.
Trim length of cases compared to chamber length; was there sufficient clearance?
Seating depth of ogive relative to lands? I.E. Avoid jam.
Hot primers?
Heavy walled brass?
Basic stuff, I know, and most likely you had those things already sorted. The other engineering issues are something I am not expert in so cant comment on those.
All the best for fast recovery.
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