One shot, two holes!?!?

[Nemo288]

If you can get a 5/16" (.3125") wooden or aluminum dowel, running it down the barrel could tell you something.
Make sure the end is flat and square.
Obviously check the revolver is empty.
Cock the hammer, then slide the dowel down the barrel keeping it touching the side of the bore at several places.
Do this a few times for each chamber.
If it hangs up at all on the cylinder face, it's out of alignment.
This would be a cheap and quick range rod solution until you get the proper tool.

It could still be slightly out of alignment even if it passes this test as the chamber throats should be several mils
(land-groove difference) bigger than the bore.
But if it fails you will know for sure what's happening.

 

[s&wchad]

We're you shooting at an indoor or outdoor range? How many tines did that happen?

Describe the backstop.

 

[Bradatlas]

Indoor range. Eight lanes. Not sure about the backstop. Looks like the typical piled up rubber stuff. Distance was seven yards and it happened multiple times. I've got more pics of a target with six shots and eight holes

 

[DDX]

Did you ever figure this out. I'm pretty sure it's the ammo. I'm having the same issue. Did noticed there appears no crimp at all.