Cale block pneumatique SRS

I think I have solved my cylinder head problem, at least in the medium / short term. there is a slight space between the cylinder and the cylinder head, when we arm the replicas with the cocking handle we exert an opposing pressure which files the cylinder head ... So I created a provisional guide in 3d printing. The result is conclusive, small bits of plastic filings on the first 10 re-loads but after nothing