Rifleman (Fallout 4)

Rifleman is a perk in Fallout 4.

Effects
Increased damage from attacks with non-automatic rifles, increased chance to cripple limbs, and partial negation of target's damage

Ranks
Rank 4 gives a 6% chance to cripple the limb you hit. Rank 5 increases this to an 8% chance. In addition, if Nuka-world is installed, Rifleman now becomes a crafting perk, mainly required for the non-automatic variant of the handmade rifle.

Affected weapons
Whether or not eligible weapons receives a bonus from this perk depends on the mods attached. A non-automatic receiver must be in place. For weapons that are pistols/revolvers in their basic state, a full size shoulder supported stock/grip must be in place (the automatic name generation must label the weapon a rifle, shotgun or scattergun, and not a pistol).

Damage total
Since the actual damage dealt is affected by damage-to-armor ratio, we can analyze how both damage increase and armor reduction affects real damage.

The following calculation assumes no criticals (which scale differently than how sneak attack multiplier scales):

$$DmgMulti=\Bigg(\Bigg[\frac{RiflemanDmgMulti}{RiflemanArmorMulti}\Bigg]^{.366}\Bigg)*RiflemanDmgMulti$$

These equations assume that the resultant damage-to-armor ratio doesn't exceed 6.45 (that the resulting damage of the weapon is at most 6.45 times the resulting armor value of the enemy).

Note: "X" represents the multiplier of this component.