The particular wording of the Bolter mastery ability of the Tactical marine has me a little unsure of its meaning. It says : The Tactical Marine gains a +10 bonus to all Ballistic Skill Tests and +2 to Damage when firing a Bolt weapon. This ability only functions in Solo Mode.

Does this mean that you get a +10 bonus to ALL BS tests (any ranged weapon), and a +2 dmg bonus with bolters?

Or just that you get a +10 bonus to BS and +2 dmg with bolters?

Or just that you get a +10 bonus to BS and +2 dmg with bolters?

This. It's named Bolter mastery, not All-shooting and Bolter-damage Mastery.

Thanks, you have answered some questions players have been quizzing me on!

One house ruled option I've come up with is giving a choice on weapon type.

So a tactical marine could choose at character creation to take instead flame mastery or plasma mastery etc. To better represent the special weapon experts in tactical marine squads.

You know I.hope I don't get flamed too badly for this but how does it make sense this ability only works in solo mode?

Because your choice between Bolter Mastery and Tactical Expertise shows your concentration on one of Tactical Marine aspects.