Sure you could use a bit softer material for the barrel because you don't need to worry about washout/wear so much. But a bit of durability would allow reuse so spent barrels could be returned for a refund, which is an ok marketing plan for the legitimate customers like Lone Star, corp guards, etc.
Also a precision milled barrel vs. a clip? You'll still need the low tolerance dimensions, and to keep that across the operating temperature range. Even the mass produced part isn't as true as for other weapons because this isn't run of the mill ammo tech and it is a new, proprietary weapon system.
I wasn't thinking hundreds of
, but maybe triple cost of a normal ammo with a 1/3 refund on barrels (which 'runners would never take advantage of except to lower costs of reloading their own). Nothing that i guess you can't gloss over i suppose, but still.