The collar adapter for the Flatline will allow you you accomidate for the alignment problems created by useing the Spyder adapter. So that will not be a problem.
You will need to drop your velocity down to the 260-265 fps range in order to utilize the Flatline better without having to compensate for the the dive/climb reaction of the paint at high velocities.
The unkown factor and actually something I would seriously expect to create more trouble than it is worth will be in the distance from the breech to the arc of the Flatline.
There wil be just enough room for the ball to hit peak velocity just prior to contacting the curved surface of the Flatline.
I would anticipate ball failure due to that extra 3/4" added by the adapter.
The normal installation of the Flatline puts the ball very close to the curved surface so there is very little room for error.
The only other gun I have seen modified to accept the Flatline was the Autococker. And in that situation they placed the base of the Flatline barrel very close to the breeched position of the ball.
If you think about the closed bolt operation of the Cocker and the distance a Flatline barrel slides into the clamping colar you can see in the picture that the ball would nearly be seated in the barrel where the curve starts.
And befor you go out looking for a cocker body to cut up...these Flatline Cockers were factory built. They cost $500 new back then and very few actually sold.
I bet that this close proximity of Flatline barrel to breech is the percise reason we have not seen a Spyder barrel adapter used to toss a Flatline on another gun.
This post has been edited by Krazy8: 23 November 2010 - 09:18 AM