I don't have experience with the sionics but I have a few BCM 11.5's and also a balistic advantage 11.3 hansen profile. Both run with and w/o my can very reliably and I haven't had any issues that I can remember. Both with standard carbine buffers and springs and anything from my duty ammo to plain old 223. I also can't remember the gas port sizes off the top of my head. I know then I emailed BA they had no problem telling me and BCM would not tell me the size.