I’m listening, you guys wouldn’t be saying it if it wasn’t true.
Supposedly, A barrel should not have a mirror finish inside
One thread on this forum showing the ECM rifled barrels, say that after they machine a barrel like that, the bore is too smooth so they have to lap it after to change the surface finish to be more ideal for what we do.
The Barrel makers that Lap their barrels
I believe ALSO, lap specifically to impart the right finish on the bore
to help prevent coppering
with a mirror finish, there is more surface contact on the bearing surface, = more coppering
Think of it like
Slick tires vs Grooved tires
Or actually more like the finish of a Golf Ball
With a Golf ball like finish, much of the bearing surface "Rides On" the surface of the bore
the more bore surface we provide, the more copper is stripped from the bullet
the surface irregularity is in microns
in effect, we want the least amount of contact without allowing any gasses to escape
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The guys using things like Flitz to polish their bore, are not helping their bore.
but they likely like the results and the barrel life they get so it dont matter much