How to Zero “ComBlock” DMR / Sniper rifle with PSO 1 Scope! How to use PSO 1 scope! 20/01/19 at 7.00am / by Rob Ski / 4 Comments How to Zero PSL 54, SVD, NDM, M91 or any DMR / Sniper rifle with PSO 1 scope! Please support AKOU, shop at Union Store!