Just finished my micro 223 suppressor. Its 3.7" long x 2" diameter. I built it to fit the same muzzle brakes that I made for my compact 223 suppressor.
This is close in length to the KNX muzzle brakes
The body, mount/blast walls, and end cap are 4130. The baffles are 17-4 stainless.
I had to use a shallower cone to fit three baffles in the short space. This was the first time I tried leaving the spacer on the cone side like an M baffle instead of the traditional built in spacer on the cone baffle.
Micro on top, my 5" compact build and then a commercial 223 suppressor
On the 7.5"