For crucible, you want either the badger ccl or the B-line trauma. Scout rifles as a whole are usually outclassed in PvP due to small maps. But in the large maps, they dominate. The scout rifles I mentioned previously (ghelion's demise would be better than a badger ccl, cause of re-roll ability) are two of the easiest to use in crucible, besides the MIDA multi-tool, which you don't have. The badger or demise does 73 damage per headshot, giving it that beauty of a 3 shot kill that you'll know from using hand cannons. Unfortunately, this class of scout rifle has less impact than the Word of Crota/Devil you Don't style of hand-cannon; and also a slower RoF. The few benefiting factors of using it are the 3 shot kill from virtually any range, the slightly larger mag capacity and reload speed, and clearer sights. The B-line trauma does approximately 43 damage per headshot, giving it a 5 shot kill, but the fire rate is quite close to the SUROS regime. This gives it a very fast TTK, at the cost of a very cramped finger. It is good for transitioning from pulse rifles or auto rifles, and is probably the best CQC scout rifle in the game (excluding MIDA). Overall, scout rifles aren't really great in the current crucible map-set, this is in part that the 2 large maps outside of DLC were removed from common playlists, and also that the smaller maps were added. They can be used quite effectively on maps with long lines of sight, such as shores of time or pantheon, but not as easily as other weapons. If you want to use scout rifles in destiny's current map-set for PvP, you will have to be dedicated, and accepting that your K/D might drop.