Can't pull a dirty patch backwards through the bore without trying real hard using a jag.
It falls off as the rod is withdrawn.
One-way, one-time only. Is a good thing I think.
Slotted holder invites pulling a dirty patch back through!
Sorta defeats cleaning the bore to do that (to me)?
Need to develop a feel for this .
Is and must be experienced! You will know when everything is "just right". Jag is right. Patch is right. Hole in rifle is right size.
"Perfect" can be felt better than measured.
A nice, smooth, one-way push through a rifle bore is a "feeling" that won't be forgotten for a lifetime if you pay attention to such things?