I'm using BRB 5E and SM Codex 5E. I don;t have access to the 6E BRB yet.

I'm trying to kit out a Chapter Master. So far i've given him a Relic Blade and a Jump Pack. I was hoping to give him a plasma pistol as well. Is this allowed? I was hoping that he could shoot the plasma pistol on turns he's not close enough to assault on. Are there any rules that prevent me from having him 1-hand the Relic Blade to draw and fire a pistol, then sheath the pistol and 2-hand the blade for close combat when it comes?

I've heard rumor that there may be precedent: a space marine tactical squad is equipped with Bolters and Bolt Pistols, but cannot assault if they fire their bolters. Some players opt to have them fire their bolt pistols and then charge to melee.

Can anyone offer any clarification on this?
Would you be able to cite any pages for reference?