See photo. Caption: An Israeli soldier next to Merkava Mark IV tanks in the Golan Heights during a military drill on May 7, 2018. (AFP PHOTO / JALAA MAREY)
I don’t think it’s something super secret but some component being temporarily protected. Otherwise I have no idea.
SEWAG Coaxial machine gun (a Browning M2 .50 cal apparently), covered to keep all that crap that’s all over the hull off and, more importantly, out of it.
CMC fnord!
It’s just a machine gun. I expect they don’t intend to use it during a drill.
As has been noted it is a machine gun. You can see it more clearly in this picture. If you want to Google more pictures that is the Israeli main battle tank Merkava.
Thnx to all.
“SEWAG”?
Semi
Educated
Wild
Ass
Guess
CMC fnord!
So that’s why all my Boolean combos on Google with “coaxial machine gun” came up empty.
FN Herstal M2, FTR.
I think.
Anyone know what the sandbag looking dealies on the turrets are?
Vehicle crew sustainment, clothing, gear, snacks. Probably some stowed camo netting as well.
“Sustainment.” A word from that bizarro language used only by the military. Have you ever inquired of Mrs. Nenno for a sustainment assessment before a picnic?
Unless I truly misunderstood the word, and “clothing, gear, and snacks” are not members of sustainment, but in addition to it.
In which case:
“Sustainment”?
You aren’t likely to get a much more detailed answer than Bear_Nenno gave you. Units typically have a load plan for the most important stuff. The load plan SOP can vary unit to unit though and levels of enforcement can also vary. Then there are all the less important, optional, and outright civilian purchased items that need to be put somewhere.
Why do tankers take so much stuff to the field? Because we can. At a relatively extreme level, somewhere there’s probably pictures of an Abrams with a 55 gallon drum strapped to the bustle rack that I could explain if I saw the unit’s bumper number. It was the company grill for one of the units in my old battalion. They took it to the field during training. The First Sergeant rotated which platoon had grill duty; profits went to the Family Readiness Group.
Because we can. 
Gotta confess, I was hoping for something more tacticool and 'splodey.
Tanks, by definition, are already tacticool and 'splodey enough.
In the video you linked what is the fat part on the barrel of the gun for (seems the Merkava has one too)?
IIRC, the .05 isn’t a coaxial, strictly speaking - it’s there for training purposes, to simulate firing the main gun. The gunner aims the 120mm, but instead of firing a very expensive tank round, he shoots a much cheaper 0.5 bullet.
Bore Evacuator.
I came across this today. Most of what would normally be a brass or steel shell is basically a cardboard tube that burns up. This leaves a bit of debris in the barrel. The bore excavator sends a puff of gas through after firing that pretty much sweeps the barrel clean after the round is fired. It’s fascinating.
That’s got some kind of weird perspective going on; those tanks look HUGE- like 15 feet tall or something, when in reality they’re not quite 9 feet tall.
I think they’re slightly upslope.
