If you've never tried it, you may be forgiven if you can't see how a peep sight could possibly work. The mind argues that the front and rear sights of a rifle must be rigorously lined up with the target, and that means the rear sight must have a notch to frame the front blade. The notion of trying to locate the front blade in the exact center of a ghostly hole seems absurd.
Yet, it works just the same, seemingly in the same fashion that a bumblebee can fly despite alleged scientific proof that it cannot.
Here's why: Your eye, an extraordinarily sensitive light-sensing instrument, will automatically center itself on the point within an aperture sight where the most light is coming through. Assuming perfect eyesight, this will be the physical center of the aperture. But the really neat thing is that even if your eyesight is less than perfect, it doesn't matter. What matters is that your eye will resolve to the point where it perceives the most light, and that point will be the same each time you line up a shot. All that remains for you to do is to line your front sight and your target up with this point.
This is where some shooters form a unfortunate opinion of the peep sight. They squint and grimace, struggling to make sure the front blade is in the center of the aperture, and still have disappointing results. The problem is that they're trying too hard. Remember that the eye will automatically align itself with the point of greatest illumination. What this means is that the shooter needs to completely forget about the rear sight and focus on the front sight and the target. The rear sight will take care of itself. Really, it will. It requires a leap of faith, but once you get the hang of it, it's like learning to ride a bike.
Now, the opinion is sometimes heard that aperture sights mounted on the existing sight base of military rifles are too far forward to be useful, and that apertures must be mounted on the rear of the receiver, a couple of inches away from the eye. This is not true. The principle described above holds for an aperture mounted on the existing sight base, in front of the receiver. However, it is true that an aperture mounted on the rear of the receiver affords a longer sight radius, which in itself will increase accuracy potential. If one is building a sporter without regard for the collector value of his rifle, this may be a good way to go. There is also the cost of installation to consider. We have no argument with those who are going this route.
However, we have found that we have a lot of company in our opinion that ease of installation and preserving the beauty and collector value of a classic military rifle easily overrule the above concerns. Besides, the sight radius for a Mojo-equipped rifle remains about the same as with the original sight.
It would be nice if an inexpensive iron replacement sight would give one the accuracy of a high power scope, but we doubt that's ever going to happen.
In the meantime, we believe Mojo sights offer the military surplus shooter the best combination of reasonable cost, high quality manufacture, ease of installation, ruggedness, good looks, and enhanced accuracy.