ya i belive its the Rifle used in the halo books as a light burst rifle that isnt the battle rifel... i can think of the number though its was in fall of reach and ghost of onyx i think. any ways ya its like the AR but has a shortend barel its the predicsor (spelling) to the AR in Halo 1
ecose....your pictures (in order) are of the Halo Wars Mark IV armor, and the Halo 2&3 Mark VI armor. What's in the concept picture in the first post seems to be Mark V armor.
The SPARTAN-II program was conceived in parallel with the development of the MJOLNIR armor. The Spartans received the first practical forms of the armor, the Mark IV, in 2525, followed by the Mark V and Mark VI in 2552. http://halo.wikia.com/wiki/Spartan_II
February 3: Contact with Harvest, an outer colony, is lost shortly after the colony itself had made contact with an unknown object. The Colonial Military Administration sends the scout ship Argo to investigate
April 20: The Argo arrives in-system and makes one confirmation transmission. No further reports are received.
October 7: A UNSC battle group consisting of one destroyer, the Heracles, under the command of Captain Veredi and two frigates the Arabia and the Vostok enters the Harvest system and discovers that everything on the planet has been completely incinerated and the surface melted down to glass. This is later dubbed "glassing". In orbit around the remains of the colony world is a single alien ship, which proceeded to attack the battle group, destroying both Arabia and Vostok and badly damaging the Heracles. Intercepted communications identify the enemy as "The Covenant". The message "Your destruction is the will of the Gods...and we are their instrument" is broadcast in UNSC language.
November 1: Vice Admiral Preston Cole mobilizes the largest space fleet in human history to retake Harvest.
Cole's fleet engages the alien warships gathered in orbit over the destroyed colony, scoring a victory (though the battle cost Cole two-thirds of his battle group). Only a last minute tactical inspiration turned the tide of battle. After returning to Earth, Cole-promoted to Admiral-learns that a number of outlying colonies have been destroyed, leaving behind no survivors. http://halo.wikia.com/wiki/Battle_of_Harvest
If I had my book right now, I'd tell you the date that the Spartans got their armor. Until then....uh....yeah.
It's a small window, but the Spartans might have got their armor in time for the Battle of Harvest.