M551 Sheridan Light Tank

The M551 was an American light tank with an aluminum hull and a steel turret. The light vehicle carried a powerful 152 mm gun that could launch missiles.  The vehicle had weak ammunition storage (as in exploding rounds).  The vehicle was weak to mines and RPG fire as well. 12 XM551 tanks were built.
Variants:
1.

76 mm M32 version

Name: M551 Sheridan
Type: Light Tank
Origin: United States
Year: 1962 (production 1966)
Produced: 1662 (both variants)

Length: 6.3 Meters
Width: 2.82 Meters
Height: 2.9 Meters
Weight: 15120 Kilograms
Speed: 70 km/h

Crew: 4

XM551 with XM103E7

Primary Armament:
-76 mm M32 OR
-105 mm XM103E7 (For XM551) OR
-105 mm M68 OR
-152 mm M81 OR
-152 mm M81 (modified) OR
-152 mm M81E1
Secondary Armament:
-12.7 mm M2 AND
-7.62 mm M73 OR
-7.62 mm M73E1 OR
-7.62 mm M219 OR

105 mm M68 mounted version

-7.62 mm M240

Gun Flexibility:
19.5° Elevation (for 7.62 also)
8° Depression (for 7.62 also)

Armor:
steel and aluminum

2.
Name: M551A1 Sheridan
Type: Light Tank
Origin: United States
Year: 1989
Produced: 1662 (both variants)

105 mm M68 with Muzzle Brake?

Length: 6.3 Meters
Width: 2.82 Meters
Height: 2.9 Meters
Weight: 15200 Kilograms
Speed: 70 km/h

Crew: 4

Primary Armament:
-105 mm NATO Standard (M68?)
-152 mm M81E1
Secondary Armament:
-12.7 mm M2 AND
-7.62 mm M240

Gun Flexibility:
19.5° Elevation (for 7.62 also)
8° Depression (for 7.62 also)

Armor:
steel and aluminum

Sources:

http://everything.explained.today/M551_Sheridan/

http://www.valka.cz/11908-M551-Sheridan-1-Tezke-zacatky

http://www.army-guide.com/eng/product3393.html

https://www.onwar.com/weapons/afv/data/usaltm551.htm

http://www.military-today.com/tanks/m551_sheridan.htm

http://forums.eugensystems.com/viewtopic.php?t=34998&start=6150

http://tanknutdave.com/the-us-m551-sheridan/

http://www.militaryfactory.com/armor/detail-page-2.asp?armor_id=30

http://www.tanks-encyclopedia.com/coldwar/US/M551_Sheridan.php

http://afvdb.50megs.com/usa/m551.html#M551A1TTS

http://fas.org/man/dod-101/sys/land/m551a1.htm