Updated OP with ranges, if you don't want to look they are here:
my singled triad 5 1/2" cpvc barrel achieves on average 15' more (using bb stephans) than a stock triad both firing flat from the same location.
another thing to note is that the singled triad all the darts were in a nice neat little pile in comparison to the triad which deviated ~ 3 ft side to side. so in short you lose 2 shots by singling, and you gain 15' and accuracy
price is under $15 (including triad) it really depends on what materials you have and if you use the glues, pvc etc for more than one mod as you get way more than you need. time, i would say this could be done in a day easily i did it over the course of 3 days partially in part due to weather for painting. or hours probably 8 actual hours of work, it all depends on how detailed you want to get.
Thats a neat idea. But why not use a Jolt? Is there a difference? Or does the Triad make it able to be in the contest?
2 things, the triad has a larger air chamber and better spring, so it can support a larger barrel the jolt cannot. the goal was not solely to make a luger but to single and improve the triad which was lacking in several aspects in my opinion.
this will most likely be entered in the contest if ranges pan out.