Belomo 1P-21 PO3-9x42 and PO4-12x42 Minuta sniper scope
As a hunting scope, one that would be used to stalk your prey at various distances, the PO 4-12x42 is very useful. It actually makes shooting accurately a little easier because the scope compensates for the bullet drop automatically. A really interesting and unique feature.
As a target scope for shooting at a fixed distance it is not ideal. Once you get the scope dialed in and zeroed properly you can never touch the magnification adjustments again or you will lose your zero and miss your target.
There are 3 adjustment wheels on the 1P21 scope, an elevation turret, windage turret, and the magnification wheel. The two turrets are not finger adjustable and are meant to be set once and not touched again. The user only adjusts the zoom power setting wheel to adjust the scope.
With the zoom set to 4 (the lowest setting), the aiming chevron in the reticle is so low in the scope image that you can't dial in the elevation adjustment turrets to compensate. I adjusted the elevation all the way to it's limit but the reticle still wasn't high enough to hit the target.
But...When I dial up the zoom power, the scope body itself starts to raise and when I get to about the 10 power setting, the aiming point in the reticle is now on target. After setting the windage and elevation turrets to zero the scope at this power setting it shot great. But if I turned the zoom power wheel (the big one closest to the eye piece) the reticle will move off the target and will no longer hit at point of aim.
Basically the scope can not operate like a traditional zoom scope. A normal scope can be zeroed at say the 4 setting then you can dial up the zoom to the 10 power or 12 power and the cosshairs are still set to point of bullet impact. Not so with this 1P21 scope. It has to be zeroed at one power setting (high in this case which is good) and never moved unless you are aiming at something further away than where you zeroed it.
As you see above, changing the magnification power will make the reticle get bigger or smaller. But the power setting markings which are the numbers around the edge of the reticle, do not change. This is because they are on two different panes of glass inside the scope. Moving the windage or elevation adjustment drums makes the reticle itself move inside the scope. Though a typical design quirk on Russian scopes, some people will find this feature annoying because the reticle will be off center in the scope when looking at it.
The front of the scope mount pivots at a thin (but very strong) piece of sheet metal. Even though the scope tube can move on the mount, it is secured very tight and will not wiggle from the recoil when the rifle is fired. This scope is designed to be mounted on the 7.62x54R PKM machinegun (as well as the SVD) and hold its zero during sustained full auto fire, so staying secure on an SVD is easily handled.
There are two 3v LED compartments on the scope body. Each LED has a rubber O gasket to keep moisture out. One LED lights the range-finder (center) reticle and the other lights the zoom power numbers that ring the inside of the reticle.
A single 3 volt battery powers the LEDs. This battery can be found at the major retail companies that sell Russian scopes.
Lastly, the 1P21 scope sits even further to the left than standard PSO and POSP scopes. Because of this left-handed shooters may find themselves unable to see through it comfortably.
The 1P21 may not be the best scope to use if you mainly shoot at paper at a fixed distance. But if you take it hunting, or are not deterred by its complicated controls, you will appreciate the high image quality of the lenses and its heavy recoil reducing weight.
From a post in the Optics section of the AK Forum Doug Ford (a.k.a. Tantal) describes the first generation version of the optic::
"This is the Pre-'85 NPZ-developed early variant PSP-1 (aka military Index code 1P21) pancreatic sniper sight, circa 1983/84. It was extensively field tested in Afghanistan on the SVD. Through these efforts, a much improved version entered pilot production at Novosibirsk by 1985 and was officially adopted by the Soviet Army in 1989. At that point in time, series production was transferred to the big Soviet optics factory located in Minsk (Zenit) in modern day Belarus. The improved version is the one we commonly know today. Normally optics don't get their GRAU codes until they are "adopted' but apparently they called this early version a 1P21 before the improved version came out, and didnt bother to change or modify the nomenclature when this was done (factory nomenclature was PSP-1). Although the mount was heavily modified, I guess the basic optical mechanism was pretty much left as is and they didnt think this called for a revision on the model designation. They do that quite often with their equipment, then at other times they seem to add a prefix code for the smallest of reasons, hehe."