Hi
If you are only trying to Zero your scope at home prior to going to a field and rather than do it there and dont want to scare neighbours then I can advise you on a Laser Bore Sight, its simply a laser pen fitted with a long rod and then using the right caliber plastic bit you slot it down the barrel, turn it on and zero your sights to the laser.
This is a cheapo one: http://www.amazon.co.uk/Red-Laser-Bore-sighter-0-177/dp/B00DSKLQFC/ref=pd_cp_200_0
Though you can find more expensive ones like the Bushnell one for £75.
I had a VSR-10 and was having issues zeroing the replica scope then remembered i bought one years ago for target shooting with the Air Training Corps (used to be an RCO).