I agree with "Inebrated", better to work on your fundamental shooting skills.
All saigas I'm familiar with have been dead-nuts accurate right out of the box, especially shooting from a rest, and at only 100 yards.
That rifle will probably take out beer cans from that distance,without even trying very hard. The AK's infamous "inaccuracy" has been over-blown, they are plenty accurate for the distances and targets they were designed for, and I've found the Saigas to be particularly tight,straight shooters.
Also, in the experience of myself and numerous others, the scope rail system on the AK's isn't the most stable and accurate. I've been through Russian PSOP scopes with the intgrated mount,as well as standard AK mounts with regular scopes, and never been happy with the results, and just went back to irons.
I would suggest shooting, from a rest again, but at a large sheet of cardboard. If you're getting good groups, but aren't hitting exactly where you're aiming, then it's a sight adjustment issue that's an easy fix. If you're all over the paper, it's probably your skills that need refining.
You might also try some different ammo, but I'm betting that won't be the issue.