Rainbow Six Siege's Operation Shifting Tides is introducing Kali, a sniper that seems to be aiming to put Glaz out of a job. Her custom sniper rifle, CSRX 300, can penetrate several walls or enemies but has some limitations.
Ubisoft's reveal video of Kali stated that her CSRX 300 sniper rifle can penetrate several walls but didn't give specific numbers on how many obstacles the bullet can go through.
For starters, the bullets from CSRX 300 can go through five operators in total, provided they line up perfectly. This was tested by SlyRecon on YouTube, where eight people lined up for the shot. The first five died instantly as it was a headshot, but this test also confirmed that there is either no damage reduction for the operators that were hit after the first one or that it was minor enough that the headshots still instantly killed all five of them.
Believe it or not, there are some instances of headshots from certain guns under specific conditions sending people into down but not out (DBNO) state.
Anyway, the number of walls CSRX 300 can shoot through is hard to determine but given the layout of the maps, it's hard to imagine people going for shots spanning beyond more than two breakable walls. The good news is the rifle's projectiles will go through two walls and instantly kill with enemies headshots or DBNO with body shots, even through two walls.
The weapon seems to instantly down with body shots, regardless of the armour type an operator has or possible overheal from Doc or Finka.
CSRX 300 rounds don't penetrate deployable shields, reinforced walls or hatches but keep in mind that the underbarrel attachment can do it. Don't attempt to kill enemies with it though as the damage it does is negligible.
Keep in mind that neither of the firing modes are effective against shield-wielding operators so if a wild Clash appears, switch to a sidearm and melee her first.