That mag is nothing more than a NOVELTY. Two types buy a mag like that.
1. More $ than Brain cells.
2. Has money to throw away for trinkets.
NOT a good choice for a PSG-1 For many reasons.
1. Tactics, mil doctorine usually dictates a sniper to move after fire. Not needed in police roles as few rounds are fired. If a police sniper fires more than a couple rounds something REALLy went wrong.
2. Noise, that mag will be VERY noisy compaired to 20rd mag. Noise can = death to a military sniper.
3. Bulky, hard to store and transport compared to a 20rd mag. Harder to change than a 20 if you plan to take it with you.
4. Weight, not as much an issue to a PO but to a military man who has to move fast and remain quiet the weight and size already adds to a 18lb rifle.
5. Cost, no PD would pay that much for a mag, EVER, been counters would flip. Military can buy factory HK for less.
Could probably think of more but this is getting long...
BrenLover