This is the rear sight on my M46 in 9.3x57. I simply filed it out a bit - and was spot-on with 270speers at 2,300fps. I used this sight and rifle to shoot a young bull moose at 200yards - it was a rather easy shot, resting my arms and rifle on the hood of my buddy's truck.
I left a bit of the original notch for the front bead to sit in. I no longer have this rifle - my Bro has it. IIRC- the 270's struck 1 1/2" high, at 50yards and still an inch high at 100.