The genuine sniper versions of the Mosin rifle don't merely have "bent bolt handle".
They have a longer bolt handle than the standard Mosin straight bolt handle that drops vertically at a right angle to the bolt body.
Wikimedia Commons* has this illustration:
Mosin sniper rifles were developed from the standard infantry rifle Model 1891/30.
Early sniper versions used the 3.87×30 PE or PEM scope (Soviet-made copy of a Zeiss design).
Later sniper rifles used the simpler and more compact Soviet 3.5×21 PU scope.
Mosins were selected for sniper rifle conversion from general issue Mosins based on showing better than average accuracy.
Because the left side scope mount placed the scope centered over the chamber, the standard Mosin bolt handle was replaced with a much longer handle at a sharp downward angle which is horizontal when raised ("bent bolt" in most collector references). As with the US M1903A4 Springfield sniper rifle, the centered location of the scope prevents the use of stripper clips and the sniper version magazine must be loaded one cartridge at a time.
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