I fucking hate identifying AR-15 type rifles in drawings because they all look so similar and the AR platform is customizable in the first place you can basically do whatever to it as long as it doesn't violate gun laws. Anyway, I'm tentatively tagging it as the T112 assault rifle based entirely on the stock and magazine though if it is the T112, it is missing the bayonet mount. It could be the XM7, but it's missing the pretty iconic looking free-floating reinforced M-LOK handguard.