SKB,
Kirk doesn't use a welder. When David McKay Brown had time to sleeve guns, he didn't use a welder. Westly Richards doesn't use a welder for sleeving either, and their guns must still pass proof.
Kirk's seams are invisible to the naked eye, but, you could see it with a 10X glass or so.
No offense, but, I'll take Kirk's sleeving work on guns over welding hands down.
Best,
Ted