The advice above is correct.
I own what your planning on buying. I gamed it twice with only one mag, and that sucked.
Before Rhino I bought 7mags more. I never went through more then 4 mags before I died and was sent back to respawn.
In the end if you feel realism/recoil is better than performance, get a GBBR. If not, I'd get an AEG.
I'd also look into some non=WE alternatives. My riffle, with ALL the RA-tech goodies, a 500mm tightbore and the 'upgraded' stinger hopup shoots like a bag of ass.
Mind you, I've waiting for my VS-Z to arrive which (in theory) should change the performance.