Here's a bit of logic - if I turned my own barrels, would the rifles I assemble from parts be worth more or less than if I continued to use the Shilen or Black Hole barrels that I currently use?

Making something yourself is only worth something if you're better at it than the guy you used to buy it from.

You live in a select market area if Del-Ton's hold value better than the Cerberus brand rifles where you live. I travel all over the US, I've yet to see that in the used market.