I bought the 2 x 21" Thunder Pigs that Sonic is talking about, one for my inferno and one for my mates.
The full cost of both barrels and 2 x 28" pull throughs came to just over the price of 1 dye excel barrel, and thats after shipping from the States. Strangely enough, although people say length does not matter, the barrels perform exceptionally well on our back up infernos. Other people have used the barrels and said the same thing. One of them, actually preferred it to the Junior Freak (.693) and the Dye Excel barrels, that I have for that marker. As something that I bought for the sheer fun they don't disappoint and they were cheap
SO DON'T KNOCK 'EM 'TIL YOU TRIED 'EM