My eyes no longer work as well with apertures as they used to, the front post doubles.
I'm finding that with the right combination of front & rear, I can still see both well enough to shoot decently with irons in the form of a VISIBLE front post & a notch rear.
The Compact Magnum .308 was shooting about 6 inches at 100 yards as it came, with that tiny bead. Once the sight was replaced by the XS blade, groups shrank to under 2 inches, with a couple going markedly lower, in exactly the same shooting conditions.
There's something about the way light transmits through the rear notch that sharpens up the front blade. I tilt the blade up out of the notch & it blurs, I put it back down in the notch & it sharpens right up.
Has to be the right configuration on the rear, not all work equally well.
I noticed the same thing on a Rossi .22 pump years ago.
Once the bead's dumped, the notch on the Ruger CM works great.
The Ruger rears with a two-level wide notch and a tiny bead are particularly hard for me to line up, but the notch on the CM is perfect.
Just a thought.
Denis