How much could the new Bushy AR 9mm be modified/customized (rails, handguards, trigger groups, etc.) as compared to the standard aluminum receiver AR15?  Are there any aspects of the Carbon 15 series weapons which lessen their relative compatibility or interchangeability with standard aftermarket AR15 accessories?

Also, how plausible would it be to utilize the Carbon 15 9mm pistol buffer tube for shoulder support?  Does anyone have a picture of the above scenario for visual reference?

Thanks    

The lower is pretty easy to work on. But for the upper getting that apart is next to impossible unless you send it back to bushmaster with the request for them to dismantle it. There is a proprietary nut on the barrel that locks the handguard on and without having a machinist make a custom tool you are not getting it off. This also makes removing the barrel impossible.