.45 caliber M1911 ball ammo comes packed in the military M2A1 ammo can also used for .50 caliber MG ammo, and often called *.50 cans*, 1000 rounds to the can, two cans per case.
Given that .40 S&W is a bit smaller than .45, I reckon that somewhere between 1200 and 1400 rounds of .40 could be so packed in the military cans, but a thousand rounds per can is a real handy figure to work with: 9000 rounds would be 9 cans full. The GI issue backpack frame used to man-carry a full 5-gallon water or fuel can can also be used to hump ammo; four cans is a pretty good load but is veryt do-able, and I've done it. Two more cand can be carried off the right side,n and another pair on the left, admittedly a pretty good load, but for a grunt in good shape, it's no big deal. That leaves one final can's worth, or 20 bozes of ammo. What won't go in ammo pouches or pockets can be carefully balanced on trhe helmet, and anything remaining can be juggled, entertaining and impressing spectators and bystanders along the way.
That may be impractical for cops, however. After all, with one's hands so occupied, there'd be no way to carry doughnuts.
I'm just glad it's not 9K of rifle ammo that needs moved. That could be rather tiring.
