JustinOther has proposed an interesting idea to me, which is to implement the xCal ammo resources via injection into the required CALIBR.ESM and rename the the bsa from xCALIBR.bsa to CALIBR.bsa.
The purpose of these proposed changes is to eliminate the need for modders to include the xCALIBR.esm by incorporating those resources directly into the mod's esm/esp and using calibr.esm to load the bsa.
I find this approach very clever but I see downsides as well.
First, it will break all existing mods that use xCal ammo. Updating mods to support the structure is fairly simple with FO3edit, but it is a manual process. I fear that the transition would be a nightmare for users.
Second, compatibility may be lost with the loss of the current single source approach. Once the resources are incorporated directly into mods, there is no longer an independent standard to ensure consistency.
I consider xCALIBR communal property, so I would really appreciate some feedback from modders on how xCal ammo can best serve your needs going forward.
Thanks for your interest and support.