Can you use Deathwatch models to proxy other Space Marine lists?

[Primarch Betalio]

I got a question regarding deathwatch veterans: Hope that you could answer it, so if I acquire a box of deathwatch veterans, what could I proxy them as in other Space Marine lists?

 

Thanks 

[Bryan Blaire]

As long as you and the other person you are playing with agree to it,  you could proxy them as anything, even non-Space Marines - a proxy for anything in a Games Workshop game is already something that doesn’t have a defined meaning, so there’s no “what could I” to answer, the limit is up to you and your opponent (or Tournament Organizer allows, if playing in a tournament).

[TrawlingCleaner]

Sternguard Veterans feel like a safe bet to proxy them as, you've got heavy bolter analohue and Bolt Rifle/Combi weapon analogues too