I have yet to see a darter that swims better with a split ring than without it.
I cut VMC hooks on most of my plugs.The only exception is my pencils and sometimes needles.I wouldn't dream on putting one on junior atom or a darter.Do they open ? Not that I ever experienced or seen.I did have a 2/0 closed eye VMC straitened out............tight drag........
To those of you who automatically add split rings to all your plugs ...a thought....
I know a well known builder who literally breaks his a** to get a swivel burred into the body as deep as possible so that the hook without the split ring doesn't hang low.Now when you add a ring you kind of defeat the purpose.....not that I am advocating that the buyer of a plug should not be able to rig it anyway it wants ,mind you......another thing ...did you ever consider that by adding a split rig you just added another thing that can possibly fail (at worst possible times of course)?
Threaded Mode