Sleeved Barrel

[BAT340]

Several years ago I bought a DWM shooter. Paid six hundred for it. When I bought it, the barrel rifling was pretty worn. The barrel wasn't original to the pistol. And, was the only non numbers matching part on the weapon. Several gunsmith's told me although worn, it could still be shot. And it did shoot fine. But on further examination, (You had to look close) the barrel had a bushing in it. It was around a 1/16 thick. and ran the full length. I eventually sent the pistol to Tom Heller to put a new barrel on it. Here's my question…Have any of you guys ever come across this before? And who would have performed this? As it was professionally done. I used to work in Tool, and Die, so I know fine machining work when I see it. It is a '08 military, converted to police use. And still shoots fine. Although now I have retired it. I can't post pic's, as I tossed it out (the barrel) a few years ago.