I looked into it quite a bit for the last rifle I put together.(bolt gun) At the end of the day there was no reduction in length at all, as the minimum barrel length for the cartridge was the same if it was integrally suppressed or screw on and then the amount past the end of the barrel is also more or less the same. Making the overall length, the same. Which, imo, eliminates any reason to do an integral.
Ya, I thought it was the solution to the barrel length problem as well, but I talked to both companies that do a bunch of them here in the states and in both cases the overall length was coming out the same.Sounds like more development work is needed then. Or at least the trade off discussion of various metrics (i.e. muzzle velocity vs noise).
It seems highly unlikely an optimized integrated solution shouldn't be able to have improvements over a modular approach.
In my career as an engineer, the only times that "seems" to happen is when significant mistakes have been made.