Talk:Mastery Rank/@comment-23485277-20131005120717/@comment-81.156.221.250-20131005125426

No, weapons/warframes only give mastery xp for each level once.

The selling/rebuying for mastery xp is only applicable if you hadn't levelled the weapon/frame to 30 in the first place before selling it, in which case you could rebuy it and level it all the way to 30 gaining mastery xp for the levels you had 'missed' before.

Example:

You level your mk1 braton to 15 (gaining 1500 mastery points) and sell it.

Later you rebuy the mk1 braton and level it all the way to 30 - you would gain no mastery points for levels 1-15 as you had already levelled those previously. You would, however, gain 1500 mastery points for levels 16-30 as this would be the first time you had reached those levels with that weapon (even though this would be the second time you had owned it).

Hope that clarifies.