To answer the OP, hopefully you're lucky. You will more-than-likely have problems running Winchester bulk, so I'd stick to Federal bulk pack at a bare minimum if I were you.
If you notice any problems running that, remove the quad-rail and see if it runs better. Some quads have been known to hinder performance since they "clamp" onto the gas system. Eventually, you're going to give in to peer pressure and do a full conversion. It's really easy and makes the weapon a lot easier to handle.
Basically, the phrase I've coined fits here nicely:
All Saigas are different, like snowflakes only more badass.
Let us know of any issues that arise and we'll get it figured out. I'd like to say that we've seen it all, but just as soon as I say that, something new pops up. We'll figure it out together, now go try some different ammo out and see what happens!