DIY 1911 Improvements?

[Wall]

If it's a bull barrel, the slide is likely not milled for a bushing anyhow, but, there are a few Officer size 1911's with a bushing'ed barrel... think Colt Defender.

Most officer size 1911's, like the Defender, used a 3" barrel.
If he has the RIA I'm thinking of it's a 4" barrel on an officer size frame.