How many animals are you planning to shoot that you need 11 lbs of ammo? For my plains game hunt a number of years ago, we shot 13 animals and fired 15 rounds. Those extra 2 rounds were fired in the range when we got into camp. I took 40 rounds, 2 boxes, and could easily have just taken one box. But, I can see why taking two boxes would be desired. I don’t recall what those two boxes weighed but probably well under 5 lbs.
Last year when we went for Buffalo, Qatar made me take the ammunition out of the locked cased and they weighed it separately from the case and then weighed it all together.
I again took 40 rounds of 375 H&H and I think my case and the ammo weighed maybe about 7 lbs if I remember correctly. I shot a total of 6 rounds. 2 on my Buffalo, 2 on my Crocodile and 2 on the range when we arrived in camp. Again, could have easily taken one box of ammo.
So, if you are overweight on your ammo, simply take some out. If you shoot well, you don’t need as much as you might think.