Well, there's some breach-block adjustments that need made for the plasma igniter, but everything else of the loading mechanics and turret can be kept the same. There's a point the increased pressure demands a new cannon design to withstand it, but you can get a good boost from a drop-in implementation.
I still want to see attempts at hybrid systems, because there's some pretty important complications you can work around by mixing chemical and electromagnetic shell propulsion, mostly regarding manipulating the pressure curve for component wear and combustion optimization. It'd be a ludicrous dick-wave of US overengineering, but it'd be neat!