Striking = Draw filing. The barrels of hand-made British guns were not contoured on a lathe. They were contoured from the rough blanks, by hand, by a skilled barrel filer. He not only had to achieve the proper contour, but had to maintain uniform proper wall thickness, all the while keeping the bore in the center. Also, the finished barrels had to be reasonably free from ripples and other distortions in the surface to be accepted for proof. Thus, finished barrels were said to be "struck-up". Barrels are "struck-off" to remove surface corrosion, dings, scratches, old finish, etc. Barrels that are particulary free from surface distortions are "well-struck". Well-struck barrels are, in part, what separate fine doubles from those of lesser quality.
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