FWIW; I have a .410 Briley Companion tube in my Perazzi TMX that cost $300. This gave me a .410 SBT with a release trigger for small gauge league shoots. I did run a 24/25 one night dropping #25 using 1/2 oz. loads. I would get the 3" chamber if I had to do it again only because I have quite a few 3" reloads. It is a fun gun to shoot.