Likely whittled out to lighten it up a bit would be my guess. Not that that was the best place or idea but it’s the best I can come up with.
This is the most likely IMO. I did a similar dishing out of the butt of a Kimber 82 that in order to make the weight limit for Smallbore Silhouette Hunting Rifle class, I did stop before I went all the way through though. It would not surprise me if this was done for the same reason.
drover
