I’m about ready to order a Centurion SPR barrel and will need a rifle length gas tube. This is my first time dealing with a low profile gas block and the need to source my own gas tube.
BCM is out of stock as are most other places I’ve looked. My lower receiver is already in route (I hope) 
from G&R, but they don’t show gas tubes (I should have asked).
Brownell’s shows a Colt “Gas Tube Assembly, Long” for ~$45 which makes me think it’s more than just the tube and roll pin. Midway has stock on an Olympic, but is that a top tier part?
And finally JP shows rifle length tubes in stock for $15, but the pics show a straight tube (no humpback)…do you have to bend these to make them fit?
Help!