Many Remington #1 Rolling Block Sporting rifle receivers have an approximately 1/8 inch 45 degree bevel between the front of the top flat and the front of the two side flats and the front face of the receiver. This allows the front of standard octagon barrel flats to match up with the bottom of this bevel.

On heavy barrel Remington #1 Rolling Block Sporting rifles, this bevel is absent and the octagon barrel flats lineup/mate with the 90 degree top and side flats of the receiver.

Question: on heavy barreled rifles, does anyone know if Remington "faced off or milled off" this bevel on the front of the receiver to mate the flats of the heavy barrel with the flats on the receiver top; or, were the receivers pulled from the production line before the bevels were made.

Just dug all my #1 Sporting Rifles out of the safe and did some measurements of the receiver length to see how they compared. I only have two heavy barrels that don't have the bevel, and one of those is an early round top sporter, so I disregarded it's length. It had a rounded front edge, and not beveled, and corners of the octagon simply hang over the rounded edge.
But the others all measured slightly different, but all around 1.60" in length front to back. None under 1.60" but some as much as 1.66" long. The one without the bevel and barrel slightly larger than the receiver is right in there with others at 1.62", so I'd say they were destined to be fitted to larger barrels before they were machined. They simply skipped the step of beveling the front edge.
But I enjoyed your question, as it's something else to look for when I see an old Rolling Block Sporter with a large barrel! If it's beveled I'll know it was likely swapped!

Glad to help John! I surely had never even thought about the bevel or lack of it on heavy barrels. When I went and looked at mine I was actually a bit surprised to notice the difference I had overlooked for so many years!
I only have 8 #1 Sporting Rifles, so not enough  to be definitive.