Only problem with the drop-in barrels is that they're heavy. If you're replacing say, a .54 barrel, your replacement barrel will have to be the same size across the flats. More steel = heavier barrel.
HOWEVER, I did it.

I have a .40 drop-in and I like it real well, I just put a sling on the gun and went about my business.
You might also consider getting a smoothbore barrel for your gun, if small game is the reason you're doing this. Quite a bit lighter and a whole lot of fun.
Have fun, whatever you decide.