I know search is not working up to snuff. But one time back there was quite a discussion of clean/dirty and break in or no break in...
Personally I like break in, especially with something like JB in our barrels. They are usually quite rough
and really benifit form some elbow grease.
As to shooting break in IMHO the finer or better the workmanship it took to make a barrel has allot to do with break in required.
I suggest this:
1) Simply go shoot it and see how and what it does. Try different ammo and be sure of the handi basics! Be sure NO OIL on latch, Be sure of snapping it closed and NOT resting on anything hard. If on a bench, use a sand bag under the hinge of the receiver. If not so good, refer to #2
2) Clean it and shoot again to see what you get.
3) If accuracy is terrible think about returning to factory under there accuracy gaurenty.
4) If not great, but not bad enough for a return to factory, try the JB and thouroughly clean all JB out and go shoot again.
5) If still not good, shoot some more to get a good ''fouling'' in the barrel and check again.
6) If it shoots good for you... carry on untill it don't any more. In that case refer to #2 of this paragraph.
CW