Talk:Zylok/@comment-118.208.109.157-20181027032521/@comment-26490685-20181027111227

Regarding the Mastery Rank requirement, this restriction (to the best of my knowledge) only applies to weapons being purchased directly from the Market, constructed in the foundry, or traded between players.

It is my understanding that completed weapons (not blueprints) received as rewards from events work the same way as weapons obtained through Prime Access, by purchasing a bundle from the in-game Market, or from a promotion (such as from Twitch Prime)--that is to say, once the completed weapon (or warframe) is in your arsenal, you can equip and use it.