The M1IP, or as now known, IPM1, did not have DU armor nor any add on armor. It did have improved armor protection v KE on its turret front as part of its design.
All M1A1AIM are about the same, some have better armor than the others. No you can't tell by looking.
All M1s & M1IPs are "light armor", all USA M1A2 (withdrawn from service) and M1A2SEP are heavy. The exception is the Egyption M1A1s and Kuaiti M1A2s, these are beleived to be light.
The M1IP has heavier and different armor than the M1, and the M1A1 improved on the armor of the MIIP, and of course the M1A1HA improved on the M1A1. From there it gets really confusing because of all the rebuilds on top of rebuilds.
Check -
http://collinsj.tripod.com/protect.htm
M1
Turret: 400
Glacis 400
M1IP/M1A1
Mantle & Turret: 450
Glacis: 350-490
Lower front hull:430-470
M1A1HA
Turret: 660-680
Glacis:560-590
Lower front hull:580-630
M1A1HC/M1A1HA+/M1A2
Turret: 880-900
Glacis:560-590
Lower front hull:580-650
M1A2 SEP
Turret: 940-960
Glacis:560-590
Lower front hull:580-650
Side Note on ammo:
M829 January of 1987.
M827 was never DU, was always tungsten, never fielded with US forces.
The M829A2 was designed to offer good performance against K5, the M829A3 is designed for potential future armor threats.
Re: M1 Abrams variants
Threaded Mode