guncrank,
It's been awhile since I was in the Louisville area, and I'm trying to remember someone in that field, close to you, that might do it free, or for a few bucks for you. By the time you ship it, two ways, and pay for the test, the guy will surely balk at the price. Most places will charge at least $50.00 for the testing on one small part, like a bolt body, etc. If it's for the entire gun, or barrel, frame, and bolt, then you're looking at a good amount due to the chemical cost. A spray can of dye is what is so expensive, as a lot is wasted when its applied.
If you know anyone working around pressure vessel manufacturing, they might be able to take it into work, and have it done for free.