I would try to stay away from carrying a second rifle with you unless you have it slung over your back with a 2 point sling to help eliminate carrying the extra weight. Your goal is to create as small as a footprint as possible. As Ricochet said you want a comfortable and light load out and I found carrying that second rifle is neither.
Also gas blow back pistols are tons of fun but for a sniper they provide the enemy with a loud sound to locate yourself. I would try a NBB like an Oasis 22LR (few on the Classifieds once you get av'd), TM MK 23 or even any EBB (anything TM) as they are significantly quieter and would allow you to get a few shots off before anyone can locate you.
Hope this helps!