Armour Type and Bolter Combos

[Slips]

Well, how many are you looking to buy? if you're getting ~20 odd suits I'd say get 1 5 man group of every mark and just mix and match and have fun -  although that'd work better with post Istvaan Legions.

[Relict]

 

Regarding armor marks, you can mix and match within reason. For example, my World Eaters have Marks II, IV, and V. In my mind, Crusade armor is reserved for heavy support squads and veteran tactical squads - Crusade armor being obsolete by the outbreak of the Horus Heresy, it makes sense that only the oldest veterans and second-line units would still have them. Almost all of my line infantry units are clad in Maximus armor. Heresy armor is reserved for my assault units since I envision their role entailing high attrition rates, necessitating hasty field repairs and salvage.

 

On top of that, certain armor marks are affiliated with specific Legions. For example, Corvus armor is prevalent within the Raven Guard and Alpha Legion, for different reasons (the Raven Guard received the bulk of the new armor following their successful field trial of said armor, while the Alpha Legion swiped the design and manufactured the new armor themselves). Iron armor is common with the IV, VII, and XIV Legions, given their leaning toward durability above all else.

 

Regarding bolter patterns, I would say that Phobos pattern goes with Crusade and Iron armor. Tigrus pattern being synonymous with Maximus armor. Personally, I treat the various bolter patterns as I would real-life firearms. To me, Phobo pattern is a rifle, Tigrus pattern is a carbine, and Umbra pattern something of a specialized variant.

 

To add: remember that the Traitors salvaged a lot of war materiel from the fields of Isstvan V. With that in mind, you can totally justify a Sons of Horus units clad in Corvus armor they had torn from dead Raven Guard.

If you want to stay strictly 'fluffy,' then I don't know that you can really justify Sons of Horus in Corvus pattern armor, unless you say that they picked it up WAY after Istvaan V. According to Deliverance Lost (which, while some might disagree, I liked), Dorn delivered the Corvus pattern to Corax after the battle to help make up his loss. Granted, it went on to say that he 'beta-tested' the armor, and I suppose it's possible that there were some units armed as such, but I feel like they were few and far between.

 

In Extermination, there are illustrations of Raven Guard in Mark IV at Isstvan V. Same goes for the Sons of Horus in the previews for the next book, Conquest. 

[Brofist]

I'm a big fan of MKIII armor + CSM chest (heresy?) chest peices for my IWs. Not crazy for the umbra pattern bolter, but I somehow really dig the umbra bolt pistol:

 

http://i.imgur.com/lCnfavh.jpg

http://i.imgur.com/l1UvEIB.jpg

http://i.imgur.com/Yrcs40j.jpg

http://i.imgur.com/CrxFbSf.jpg

[Reyner]

My Sons of Horus will be in mostly Mk4.. Mostly. Whereas my Iron Warriors will be mostly Mk3 and Mk2 - the Iron Warriors are a company that was on the arse end of nowhere using older tech and the Sons of Horus will have the newest, shiniest toys (still might paint my Sicaran as Iron Warriors though as it looks awesome).

[Anvilarium]

In Extermination, there are illustrations of Raven Guard in Mark IV at Isstvan V. Same goes for the Sons of Horus in the previews for the next book, Conquest.

You mean Mark VI, not Mark IV, right?

The Sons of Horus did not have Corvus Armour at Isstvan. However the Raven Guard did, and so did the Alpha Legion. The Raven Guard had prototype Corvus Armour which they were field testing on behalf of the Mechanicum.

However the reason for the Alpha Legion having a LOT of Corvus Suits at Isstvan isn't fully known. It is suggested in Extermination that they intercepted the design plans for the prototype and began to mass produce their own suits in secret.