Shattering Impact is a melee mod that permanently reduces an enemy's base armor by 1 per rank upon dealing Script error: The function "Proc" does not exist. damage with a melee weapon.
Due to the nature of in-game damage calculation and quantization, a few melee weapons are unable to gain the effects of Shattering Impact even though they have a non-zero value of Script error: The function "Proc" does not exist. damage:
Shattering Impact takes effect on every melee hit from weapons with any Impact damage. It has no effect if the melee weapon's Impact damage is zero. Note that it is not necessary to proc the Script error: The function "Proc" does not exist. status effect to trigger the armor reduction.
The amount of armor reduction per hit is a flat, constant value, independent of the amount of Script error: The function "Proc" does not exist. damage inflicted. Since the reduction is applied to the target's base armor, for a given enemy type it will always take the same number of hits to completely drain the enemy's armor, regardless of its level.
Compared to Script error: The function "Proc" does not exist. statuses, Shattering Impact has the ability to reduce a target's armor to 0 instead of just by 80%. Corrosive, however, only needs 10 procs to achieve this, while Shattering Impact may require a substantially higher amount of hits for the same effect on enemies with high base armor.
Shattering Impact is able to affect status immune enemies, such as bosses.
As of update 18.1.4 Shattering Impact doesn't reduce enemy armor when used with the charge attacks of thrown weapons. The charge attack from a Blade and Whip type weapon will however reduce enemy armor.
Tips
The mod is most useful against enemies with low amounts of base armor, and at high enemy levels.
Valkyr, Volt and Gauss, with proper mods, can deplete even high base armor in a short time using Warcry, Speed and Redline, and a stance with multi-hit combos.
The mod is most useful on melee weapons with high attack speed, and on stances which involve applying multiple discrete instances of damage on the same keystroke. Due to its demand for high attack speed, this mod has good synergy with Fury, "Berserker" wasn't found in Module:Mods/data and Gladiator Vice on weapons with decent amounts of base critical hit chances, and by extension with True Steel or Blood Rush, as they both facilitate the build-up and maintenance of the Berserker bonus.
Bugs
This mod does not have a description in the Polish and Spanish Warframe Clients.
Very often the armor reduction from Shattering Impact appears to only be able to be applied by the host as the health bar remains yellow for the clients. However, the actual effects from the armor stripping are applicable for the whole squad.
Valkyr, 
