I measured the barrel channel at the tip an its an inch wide so it should be close. Rem varmint barrels are what .830 at the muzzle so I would expect they would .850-900 at the tip of the stock whick would clear well. It looks like it was just cleaned up to float the factory sized barrel.
I dont have a rem barrel to try it on but tried a savage varmint barrel in it an it looked nice. Sorry for lack of exact info but this was my brothers stock.
Give me a cpl an Ill shoot a pick of it with a barrel.