I would actually prefer the 26" to be 28 or 29" (optimal length) and then the short could easily go 18 or 20".
The 50bmg needs at least a 29'' barrel to burn all its powder .. Any .50bmg with a barrel under 26'' is just a novelty gun in my opinion , very nasty to shoot unless you like huge fireballs, excessive concussion and recoil , and greatly reduced velocity..