I have a 2nd year 760 that is drilled tapped (non-factory of course). I want to put an aperture sight on it, (Williams WGRS) but I want to ensure the drill/tap that was done will work.

If anyone can give me a few measurements I would truly appreciate it. Center/center rear screws and maybe front rear screw to front of receiver.

Thanks

An option is to use the rear base mount screw holes, and mount an aperture sight there. My dad's rifle was so equipped and it was fine.

That's what I want to do, but I need to know if these holes match the holes on factory D&T rifles. Since this rifle didn't leave the factory D&T for scope mounts, I don't know if the person that D&T the rifle did it to match a factory D&T rifle. So if the holes/spacing is different than your recommendation will not work, and that is what I am hoping to find out.

There is also the matter of screw size. Remington used #6 screws for their pumps and autos of this pattern up until the 7400/7600 series, which use #8 screws. You'll need to determine what size screws yours was tapped for, before you select a sight base.

They are a 6-48.

the weaver #62 plate is the standard for the remington 760, so you can get one to confirm. the rear hole spacing is .605 on center, the front is .860. the 760's were drilled and tapped 6x48. the one item that might not fit up is the contour on the slope of the peep sight base might not fit the slope of the rifle depending on where the holes are drilled on the rifle.

If it's already got a weaver base on it you could probably use one of the back up aperture sights designed to attach to those bases. You might need to change the height of your front sight however.

https://www.amazon.com/XS-Sight-Systems-WB-2000N-L-Backup/dp/B00PNDXOB6