Being a master carpenter I can say that's a very good job. Next, it's southern yellow pine, not a lightweight wood. Put the full 20 muskets in at about 10lb apiece and the crate itself likely coming in at about 20lb and it's not light. Here's a pic of one I made. It's not really authentic per se, but it's designed to hold the muskets I use when doing black powder instruction.
View attachment 464571
And for something much more refined, a replica Whitworth case with a Parker Hale replica Whitworth. I copied the case from an original with some refinements.
View attachment 464572