GW released some beta rules to make bolters (and bolt related weapons) more effective in the hands of Marines (Loyal/Heretic/Dark Angel*/Alpha Legion* or otherwise)
https://www.warhammer-community.com/201 ... ge-post-4/
I can't see anything saying you can't apply them to KT games, so dropping the link here.
* as I typed this I was thinking 'depending on how you fluff your marines'. But I imagine it's only the Emperor's Children that are into fluffing...