The 300 Fireball in the picture below now has a 16" Olympic Arms barrel. I am going to SBR this weapon with a new 10.5" Shilen barrel. I have read through many posts and still do not know which gas port position and size to specify. I will only shoot 220 Sierra Match Kings at subsonic velocities through this weapon with a sound suppressor always installed.
The weapon functions perfectly with subsonics now with the standard Olympic Arms position and size. Should I ask the gunsmith to duplicate the Olympic Arms barrel relative to the gas port or should I specify the standard AR-15 pistol position and another specific size?
What is the optimum gas port location and size for a 10.5" barrel shooting subsonics through a sound suppressor?
