Willie, not arguing with you, just presenting a different point of view / opinion, based on my experiences in alligning a lot of rotating connecting power drive shafts.
actually if the wedge holes and the wedge are properly machined.
Meaning the wedge holes in the arbor and the barrel assembly are in
perfect alignment with each other and are cut square to each other, And the wedge is properly shaped with the same taper from heel to toe on both sides, Then as long as the arbor does not bottom out in the arbor hole, then theoretically it would not matter how tight you press the wedge.
The muzzle side of wedge will push assembly one way, and the cylinder side an equal amount the other way, balancing out.
Now if the wedge does not have an equal taper, or the holes are not square or in perfect alignment, then yes, the wedge could / would cause the gap to change. It will get tighter at the top because the frame will give at the top somewhat because of no rigid topstrap,
Since Colt does not have a topstrap we have a weak point that can give if excess pressure is applied, if the above alignments are not perfect, and they rarely are,
In both my old walker (about 3 yrs) and the new one.
finger pressure alone I can engage the wedge until the spring on the toe end just pops up to lock.
The cylinder spins freely,and I can NOT slip a .002 inch feeler gauge between cylinder face and the forcing cone, even pulling back on the cylinder.
however, on both I did need to do a little dressing up of the hole and wedge to get this.
Before I dressed the holes and wedge, I could not press hard enough with fingers to lock the spring. I used a tapping hammer. And when it locked, I could not spin the cylinder.
Now moderate finger pressure can lock and unlock the wedge.
But the arbor being too short in and of itself doesnot matter. If the wedge and wedge holes are equally shaped. Matter of fact the arbor should not bottom out tight in the arbor hole.
That could cause the wedge holes to be out of alignment in reverse. They need 2 to 4 thousandths float.
I base this on being a machine works tech for 20 some years, where I had to align and assemble various rotating assemblies in different production plants. If mating holes weren't in perfect alinment along a shaft length, and they rarely were, then you needed to have some end play to make the alignment.