What are the effects of out of spec cylinder to barrel gap?

[JonF]

In both the cases of too *large* a gap and too *little* a gap? I can imagine some obvious ones such as rubbing and pressure loss but what else is there?

Gap too big:
pressure/velocity/accuracy loss?

Gap too small:
rubbing/binding?

 

[9mmepiphany]

it's been awhile since i had one adjusted, but i seem to remember the range was .003-.005

too small a gap and you risk jamming the cylinder as fouling builds up

too large a gap and you end up with sideblast as the bullet jumps the gap

 

[nicholst55]

You will also experience reduced velocity with a too-large gap.

 

[The Lone Haranguer]

Large gap: excessive cylinder blast and particle spitting
Small gap: may cause cylinder drag/bind on the forcing cone as the revolver heats up