I have hunted Vermont all my life and never saw anything like that. Our rubs are seldom larger than a 6" diameter tree. Lack of mature deer and a poor buck doe ratio probably account for that. I started to hunt the mid west and trees rubbed that large are fairly common.

not high enough for a bear, almost too low for a buck, if there are no marks anywhere else on the circumference of the tree (especialy the small sprout the rifle is against) I'm gonna go with porcupine.
RR

The bear trees I have seen went much higher. They often mark their terrain and over time really rip up the whole side of a much larger tree like a hemlock. I have never seen a coon rub a tree but don't doubt they do since they climb them. I blew up the picture and pretty sure it is a deer rub. I can see a spot well above the initial rub where a tine caught the bark. the deer I have seen rubbing a tree tend to do that lower rather than head high on a tree.

as deer rub, the curve of the main beam and the tall tines will leave a lot of marks, if there are no marks on the sides or back of this tree, if it is a deer its a very small buck rubbing.
bears stand up to mark trees, it not only leaves scent but shows other male bears how tall they are.
RR

Yes you're right about that, it must of had some big brow tines because it was able to dig very deep into that live tree, it is also right in the middle of a rub line of typical looking buck rubs.

I also think it's to high for a coon to do that compared to the size of the gun

The tree in the picture looks to still have the bark on it to me. Generally bears will be standing on their hind legs when they mark their boundrys. So will cats. The height can give some indication of the size of the critter.

The OP's pic looks more like a feline scratching post to me. Here is a bobcat scratching post in the mountains where I hunt. Notice the over all height from the base of the rock. Altho the discoloration of the tree is very obvious, it doesn't go completley through to outer bark of the tree.