I just got my can and want to make a subsonic close range (1-200 Yard) gun I can shoot in my yard. I have a couple extra LRPV's and want to turn one into a 300 Whisper. My main questions are; the LRPV has a huge barrel I dont want to go that big, maybe a light varmint in a 16.5 to 18" will this work well with considering the LRPV has the large shank? are Douglas barrells any good. I have one on a 7mm-08 and dont think it is a high quality barrell it shoots OK but doesnt clean or stay clean as well as Kreigers or Harts. any other tips for building a suppressed subsonic rifle would be greatly appreciated.