Those are not sterile and using them is pure stupidity. If you decide to go that route you will definitely need to refilter your gear to ensure there are no impurities in it.
I have done a considerable amount of homebrewing. You can purchase larger syringes. Typically when I brew up a batch of gear, I will use a 10ml or 20ml. They even make them in 60ml sizes.
And remember to ALWAYS use sterile equipment when messing with gear.
http://www.researchsupply.net/syringes.html