First off I'm well into 50 engrams and only two masterworks from them. The other 11 are from zavalla. If I have to core every gun because the ones dropping are always crap. There is an issue right there. So my suggestion is either .25 core for legendary weapons that are scrapped and FREE CONVERSION TO 1 CORE. If they don't do that then all drops from nightfall and raid engrams are guaranteed masterwork weapons.