I have to assume you have some 12L14 to machine yourself?
I have made many smooth bore 'toy' barrels. Just a plain rod with a threaded breach plug, strapped to a 'carriage' or even 2 x 4. Drill a hole for cannon fuse and BAM- instant fun!! Brass, bronze, stainless, 12L14, all sorts of stuff.
I never saw anything make real 'wear issues'. Lead balls, steel dowel rods, stupid overcharges, all manner of stuff that shall remain unmentioned.
The corrosion was the only real factor in anything. I have put 12L14 to some bad pressures, I never saw or measured any deformation.
I'm comfortable using it, but personally I wouldn't expect to see it in a purchased ML. It is easy to machine but I don't see any barrel manufacturers using it. Biggest problem is keeping the bore concetric to the OD, If you drill from each end you WILL get a mismatch; unless you have gun drilling machine...
Nothing here to imply you are actually going to rifle cut it.