In the case of the Lee-Enfield, using the middle finger allowed the 'trigger' finger to be used bat up the bolt handle. This is how 'speed shooting' is accomplished with the Lee-Enfield.
The bolt handle on the Posion/Nagant is too far forward for this technique to be effectively employed.
The bolt handle on the Posion/Nagant is too far forward for this technique to be effectively employed.