I agree with 2holer. Any flaw in the barrel wall would weaken it. Why is a barrel stamping, especially in the chamber area, of no concern?
Looked at another way: If the wall is thick enough to take a deep barrel stamp and still have the appropriate strength, it is overbuilt. Why not stamp elsewhere (like somewhere on the edge of the flat), and make the barrel wall thinner?
--shinbone
1) There's margin well above the minimums (relatively low stress). 2) The steel in barrels is of low strength and low hardness and therefore is ductile and flaws like stampings and fancy engraving on the breach (commonly wedges and lightning bolts) have little significance on fatigue cracking. 3) you could make the barrel wall thinner, the stress will go up, and then the surface becomes more critical.
