I was thinking about this and I realized that, with the new way that Chapter Master re-rolls work (i.e. you aren't forced to just re-roll misses; you can instead re-roll any dice, including hits), you can actually make Infiltrator squads pretty effective against high toughness targets like vehicles and monsters.
For example, a 10 man squad of Imperial Fist Infiltrators (with Tactical Doctrine on for AP-1) shooting against a T7 Rhino would normally get about 16-17 hits, 5-6 wounds, and 2-3 damage inflicted after the Rhino's Armor Saves.
However, if you have a nearby Chapter Master and use him to re-roll everything but 6s to Hit, that means you would get an average of 6-7 unmodified 6s, which translates to automatic 12-14 wounds (thanks to IF Chapter Tactics and the auto-wound mechanic on unmodified 6s to Hit for Infiltrator Bolters), plus another 2-3 wounds from the none auto-hit rolls... that comes to an average of somewhere between 14-17 wounds total and 7-9 damage inflicted after armor saves.... so, basically, about three times the damage against the Rhino because your are "forcing" re-rolls of all to Hit rolls except 6s in order to maximize your chance of getting more unmodified 6s (which in turn double themselves, thanks to IF Chapter Tactics, and become auto-wounds, thanks to Infiltrator's special Bolter rules.
So, what does all this mean? Well, it means that an IF Chapter Master with the Relic MCed Stalker Bolt Rifle and a 10 Man squad of nearby Infiltrators could kill a Rhino or Wave Serpent or Ghost Ark or Chimera with just "average" shooting from their small fire. Alternately, an IF Chapter Master with three full 10 Marine squads of Infiltrators nearby could realistically take down an Imperial Knight in a single shooting phase.