Shotgun Slug Causing Two Impact Holes

[Pwnsaur]

Not sure if any of you had this problem, but I recently bought a case of Score Low Recoil Rifled Slug 12 Ga 2 3/4" 1 oz and fired about 50 rounds at the range. Every round fired cause two impact holes roughly the same size instead of the a single one. I've never had this issue before with any of the Challenger or Federal slugs with the same calibre and weight.

Edit: Could this be the Wad causing the second hole? I was shooting at about 15 yards.

[OkayShooter]

Wad going thru the target?

[250 sav]

Ones the slug the other is the wad/base of the slug.

[Pwnsaur]

Thanks all - that's probably what it is.

Was difficult to describe in google.