Philip,
The barrels you show are very similar to Michael Tromner's barrell (Matchlock)
His was Tusco Emilian C 1525 if I recall correctly.
Also two rifles (I believe both are rifled) once the property of Henry V111 had the same fluting, and interestingly came from the same workshop but 1540's.
I will come back with a link and photo.
BTW,
I have yet to tackle a fluted barrel! If you have details on this work, please let me know. :
Link to Michael's thread;
http://www.vikingsword.com/vb/showth...ight=Matchlock
As can be seen barrels were getting longer between the 1520's and 40's.