I used to be a tanker, so maybe I can help shed some light on this.  A lot of my NCOs were Desert Storm vets, and several of them mentioned lugging around two tactical nukes at any given time while in theater.  They were in the ammo rack mounted behind the TC rather than behind the loader, so it would have been really difficult to accidentally load one when you meant to load a sabot (would be the last and most embarrassing thing you ever did).  Given the extremely low yield of the warhead these nukes supposedly packed, and that you could fire one over 88km at max gun tube elevation, you would be pretty safe from harm.  Particularly if your driver had the sense to haul ass the other direction right after you fired.

I never personally saw any nukes, so it's entirely possible that the round was phased out before I got in ('06).  However, the fire control systems of the newest iteration of the Abrams have load-specific ballistic data, i.e. it uses a set of targeting parameters for sabot, a different set for HEAT, etc.  There was one which required a typed authorization key, and only gave a model number (since forgotten), and we always assumed it was nuclear.  My loader once asked about it while we were training up on the SEP gunnery system and was curtly informed that the question was beyond his clearance.  Which pretty much answered that question as definitively as "neither confirm nor deny".

 

As for the depleted uranium in the armor and sabot rounds, I'm not sure exactly how hazardous it is.  I do know (courtesy of an ex in a chemical unit) that the armor will trip a geiger counter, but only on contact and even then at really low levels, like 1-5 counts per second.  I'm not qualified to guess whether or not the small amount of DU in the penetrator of a sabot round is likely to cause birth defects just from chilling in the desert for X number of years, but I do occasionally wonder about the risks associated with hanging out around the stuff as much as tankers do.  Some of those guys have been on tracks for 20 years soaking up the occasional rem.

 

Hypothetically, tactical nukes likely wouldn't be used against human-wave threats...that's what canister is for.  Basically a 120mm shotgun, using depleted uranium pellets.  I understand the stuff is useful, but do we have to put it in everything?

 

Nuclear engines for tanks are probably a bad idea, though.  Yes, you'd get an incredible power-to-weight ratio and hardly ever need to refuel, but tanks have always been bullet magnets and if one took an RPG and started leaking by the curie the EPA would be all over that like white on rice on a paper plate in a blizzard.

I think your NCO's were sending you on a chase for grid squares and ground guides.

 

No way in hell have M1's been running around the battlefield with nukies in the ammo racks. Just not going to happen.

 

155mm Arty units were, in fact, prepared to use nuclear weapons. Had an interesting convo with my commander (RIP, LTC James) about that. It was a duty given to the junior Lt., because no one wanted to handle the mission for long, and the chances of actually using the damned things was so remote no one took it seriously.

An M1 can fire a round 88km (55 miles) at maximum elevation?

 

Someone must have pulled your leg until it came off.

I don't ever see it happening due to several factors...

 

1. The insecurity of the weapon on such a mobile and relatively easy to destroy platform; rolling dirty-bombs on the field.

2. PRP handling considerations...and if you don't know what PRP is, you have never been remotely close to a nuke.

Hell, i guess those two reasons are enough.

 

 

Back away from the 'Halo" games...slowly.