I use meduim to allow the trigger to be cocked without an extension. I am one of the many that had misfires with a hammer extension and never a misfire without an extension.
Well, that certainly is the arguement against the hammer extensions. And if the medium rings get you the setup and trajectory you need, then you have all you need...
I think part of the problem with misfires, if indeed they do occur from the hammer extensions, might be the brand name of the one installed. I know the ones I have are the best as far as I am concerned--I will stop at that, since brand name can be a problem...
Sorry for straying away from the ring's question...
BCB