I have Max Flow bushings available
for several guns. My Max Flows are bored out to the maximum ID allowed before
the walls collapse. The Marauder bushings, specifically, are bored to 4mm.
A wider ID allows for more
airflow, which allows for more power. Thousands sold over the last decade.
Rifle only, not the Marauder
.177 and .22 Max Flow Bushing (OEM on left, MF on
.25 Max Flow Bushing (OEM on left, MF on right)