This is coolbert:
As extracted from that prior blog entry:
* "'The M60 series has instrumentation that allows indirect fire as ad-hoc artillery if needed by virtue of having a M28A1/M28E1 azimuth indicator and M13A3 quadrant elevation on board.'
THIS WAS A POPULAR TECHNIQUE USED WIDELY DURING THE KOREAN WAR. TANKS DRIVING UP UNTO A PRE-CONSTRUCTED WEDGE-SHAPED FIRING RAMP ABLE TO ELEVATE THE MAIN GUN BEYOND HORIZONTAL AND EMPLOY FIRE [HE-FRAG?] IN AN INDIRECT MANNER RECEIVING TARGETING DATA AS WOULD ANY ARTILLERY PIECE!"
See this You Tube video [24 seconds] showing exactly this was done. That is a M-48 tank firing?
"Tanks as Artillery - Indirect Fire - Korean War"
The current M1 Abrams cannot be used in such a manner. And even if the intention was to do so the ammo as fired not effective. High-explosive-fragmentation [HE-Frag] as fired from a tank NOT in the inventory.
That M60 tank also having that internal telephone with an outside connection using a twisted pair of telephone wire [WD-1] allows the machine to be connection to a switchboard and the outside world that would include an artillery fire direction control WITHOUT using radio communications!