Few barrelmakers actually fit the breechface to the bore. It is not a safety issue at all, as many original guns were breeched the same way. It's a cleaning issue for me. I hate a gap between the end of the bore and the face of the plug.
This breeching takes a LOT of time, because now you need to time the plug to hit the back of the bbl and the bore faces at the same time. Tricky, and VERY hard if not impossible to do without a lathe.
To save yourself a headache later on, you must really check your barrel breeching BEFORE you inlet it, fit lugs, etc., just in case you need to set it back 1/16.