I did general gunsmithing for a couple years, taking in mostly repairs and recoil pad jobs. Every once in a while something unusual would come in. One day, some ol trap shooter brought in a 870 barrel that had this big ol tall bridge truss of a rib on it. I'm talking like 2" tall. It was a real piece of nice machine work on that rib. It had little posts at the muzzle, mid point, and breach, which had male dovetails. The rib had the other half of the dovetails and the dovetail was damaged. He wanted it repaired. I welded it up and refinished it to his satisfaction. When he came to get the gun, he asked if it could be ported. I wasn't in the store, but apparently the clerk said I could probably do it. I did. I simply copied a Browning sporting clays gun port pattern. I used an indexing head on a mill and drilled the holes undersize followed by openning them up with a brand new carbide endmill. Then I lightly honed the bores to deburr it. Never heard back from that guy. It was always that way when nothing was wrong.
