The Tigr really should not be fed Heavy Ball. It CAN shoot it, but if you shoot it enough you will shoot it loose. It can take it better than a PSL, but for best results, you should treat it like a PSL and only shoot light ball. There's some 160 grain (or so) Winchester ammo available, though, and this should be fine to shoot in a Tigr. It's closer to light ball than heavy.
I feed my PSL PRVI Partisan 150 grain and Wolf Gold 150 grain. I have a spam can of Russian surplus, but I avoid shooting it because cleaning it out of a gas-operated rifle is a royal dog and uses too much cleaning supplies.
Non-corrosive: boresnake the barrel, swab the gas tube, and dip the bolt head and piston head in the solvent. Clean gun in 5 minutes.
Corrosive: deep cleaning involving pouring water down the gas port, careful cleaning of the bolt and chamber, careful cleaning of the bore. Clean gun in around 30 minutes to an hour (depending on various things), 1/4 a bottle of solvent used, and a lot of patches.
For the amount of ammo I shoot per outing, I estimate each bullet is now worth quite a bit more than the PRVI Partisan due to the thoroughness of cleaning required.
Lesson learned: it doesn't pay to shoot corrosive ammo in a semi-automatic 7.62x54R rifle.