Daryl,
Thanks my Newman 20Ga have 15,4mm (.606") and 15,2mm (.599").
I use a caliper so I think it is a little on the conservative side.
Im puzzled about how it works.
As it accelerate, why do the patch do not fold back?
I mean, why do it stay put flying throug the .61" barrel?
I know: if it works do not fix it...... LOL.
I will have to try it.
Thanks
Martin