Making a LRPV into a 300 Whisper

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.

Try this site they have lots of info on the 300 Whisper.

http://www.quarterbore.com/

i have done quite a few of them from a magnum contour to a a straight 1.20" barrel and they have all shot well. You can't go wrong with a Brux barrel.

A couple of the ones Devin built are my barrels. One is a savage rifle and the other is an AR. They both shoot supersonic and subsonic very well. The savage rifle is a straight 1.20 barrel that is 16in long. It is very heavy as well.