Okay, thanks. I am wondering about the viability of having a family of CTA cartridges of varying lengths like with shotguns. I'm thinking that it might ease logistics a little as a weapon could fire any cartridge shorter than it's class. For instance an assault rifle could use the pistol length cartridges and a machine gun could use intermediate cartridges etc. This would be a nightmare for twist rates so I suppose a smoothbore barrel would be needed and would side step the free bore issue entirely. What do you think?