I guess I'm more worried about the weight rather than muzzle diameter. 30 cal
Like said above, you need to make sure that the end diameter of the barrel is larger enough for the silencer.
An example is Thunderbeast. They have specs that say the minimum diameter for a given thread for your CB or direct thread can. It's not just being able to thread it, it needs something to butt up against. There are some smiths out there that will make a sleeve of some sort that will increase the diameter of the barrel at the end.
An example of what I have just done is similar to what you are thinking.
I have a 25" #3 barrel on my 6.5-06. The diameter was too small for a 5/8-24 CB brake according to Thunderbeast, so I had to purchase a 9/16-24 CB.
As far as POI shift or other issues, I dont know yet. I just got it back from the gunsmith and haven't shot it.
Go to the Tikka forums if you want more research on it. Those guys are using cans on their T3's but are cutting them back.
Also as stated before, a carbon barrel may be the better choice. That is what I am planning on y next build for my can. Just haven't decided on what cal yet.
If you are worried about the weight of the barrel, then you really need to look at the weight of the can. There is a big weight different between them.
Hope this helps