First, put your straight edge flat on the front of the receiver letting the straight edge go over the rear of the receiver. I suspect that you will find that the front and the rear of the receiver are parallel. Not the same height but parallel. Measure the difference between the bottom of the straight edge and the top of the rear of the receiver. That will be the difference in base height. The receiver sure looks like a Remington or clone and as pointed out the bases are different height.
Last edited by dian; 03/25/24.
