I use an Armson SSR 2 piece barrel on my RT and it works great, 3 different lengths available 11", 13" & 16" nice barrel and really well made.I also have a boomstick but will reach for my Armson 9times outta 10
used to use a 14" jacko on mine and it rocked!
dont think they make them any more so you would have to search through the classifieds or post a "wanted" well worth the price you would pay, not much at that!
highly recommended!
good luck