User blog comment:Kuro-kon/Question about starting a space marine Chapter/@comment-8395098-20140819040647

there are technicallities around the no Sm with authority over guard ruling, but those are highly frowned upon in lore and here, as the majority of those who used those technicalites all ended up as traitors. or are the ultrasmurfs.

easy way is employing additional chapter serfs to serve as drivers and protection for the chapter's vehicles. but other simple thing is just to make SM who arn't complete dicks and actually listen to what a general has to say (little over half IG generals are actually very compitent) and work in conjunction with the IG instead of being as before complete dicks and completely ruining the imperial strategy or just sitting back waiting for a opponent worthy of their attentions. there are some good SM examples of that laying here and there on the sight (plenty of poor examples too but that's side the point)

as for the nid arms lore is the holy word here, but if the chapter is willing to suffer some ordo xenos investigations, and possible censurship by a stick up the bum ordo xeno inquisitor they could possibly loot the bodies of a few DE if they managed to kill them.