im unable to dig up any info on the maximum cpu cooler height for the frontech army
only case dimensions , your case is 174mm (W) so i would go for a cooler 150mm or under to allow for room behind the mobo tray , standoffs and mobo
the coolermaster hyper TX3 evo stands 136mm tall and should fit in your case and is compatible with the fx 6300 and will perform better than your stock cooler
http://www.theitdepot.com/search.html?keywords=hyper+tx3&searchcategory=0&Search=