Dreamline calibre changes?

[Baiman]

Okay guys, question for you...
I'm in the market for a dreamline and the interchangeable barrel system is part of the draw; Ive read all the reviews, watched all the vids I can find etc. HOWEVER, I just read this in an advert from a trade seller on another site:

"a secondhand FX dreamline lite, with a 300c carbon bottle and two barrels (380mm .177 and 500mm .22) runs at 11ftlbs on the .177 barrel and 8.8ftlbs on the .22. gun cosmetically has a few small marks"

So, my question is quite simple (I hope!). If a Dreamline supplied in .177 tuned to 11ft/lb produces only 8.8ft/lb with a .22 barrel (presumeably due to the AT) then if you were to buy a .22 rifle, supplied tuned to (presumeably) 11ft/lb then would it not stand to reason that it would exceed the legal limit if a .177 barrel was fitted to a rifle supplied tuned for .22? Surely that can't be right?! I'm only working from the figures they provided and yes I know that ft/lb as a measurement is almost useless without pellet weight and fps data too, but is there something obvious here I'm missing?

The .177 barrel described at 380mm is the 'compact' variant and is turning out 11ft/lb. I'd have thought the longer 500mm .22 would produce higher ME than the 400mm .22 'compact' barrel... which suggests that a 400mm .22 'compact' barrel would produce lower than 8.8ft/lb. My mind boggles, surely something about the info in the ad is amiss? Does the FX have keyway selector or similar that auto tunes the rifle when you change the calibre?? Thats my best guess so far, but so much of the above goes against my limited understanding of how barrel length and calibre affect the velocity of a pellet, given a set volume of air at a regulated pressure. I was planning on fitting the 300mm .25 barrel as it'll be used predominantly on rats at ranges inside 15 yards... now having my doubts. Any feedback from Dreamline owners with multiple barrels would be great, as would anyones analysis of the figures provided in the ad. Thanks in advance

[Spray1Mark]

They must have the .177 & .22 figures reversed, you need to run a sub 12 380mm .177 really hard to get it near 12, putting a .22 500mm on would put you way over unless the TP on the .22 barrel is absolutely minescule!

[Baiman]

They must have the .177 & .22 figures reversed, you need to run a sub 12 380mm .177 really hard to get it near 12, putting a .22 500mm on would put you way over unless the TP on the .22 barrel is absolutely minescule!

Thanks Mark, thought that would have been the correct effect, thanks for confirming! Though I was going mad there for a second, tried recalling where n when I first started learning about this and realised it was the warning at point of sale when the Theoben gas ram came out in the 90s!

[Spray1Mark]

Yes the good old "dont fit a .177 strut to a .22 as you will make it over the legal limit" best sales pitch I ever saw LOL!