Threaded bull barrel?

[MagnumWill]

Recently, I have been looking around for something that may not exist, so I will be willing to have something made. I'm looking around for a bull barrel for my New Agent, but a threaded one . I think a Defender 3.5" barrel would be perfect, but my issue is the barrel ramp. I'm worried about using a 3.5" barrel in the gun won't lock up properly. Does anyone know if a bull barrel that doesn't have a barrel ramp cut? I could have one cut, just in the 3" position so the rest can be threaded.