STRENGTH

[15 POINTS]

Take 45% less damage from your opponents' melee attacks

Your shotguns now do +20% damage

Your shotguns now do +20% damage

Your shotguns now do +20% damage

Shotguns now weigh 90% less and you reload them 30% faster

Strength increases your maximum carry weight which is quite important if you plan to carry a bunch of grenades with you. Also, you should pick Scattershot and the Shotgunner Perks to increase your close-range DPS

PERCEPTION

[6 POINTS]

Your shotguns have excellent accuracy and spread

Your explosives detonate with twice the radius

See a throwing arc when tossing thrown weapons, and they fly 15% further

Perception has several interesting Perks for a Grenadier character, as well as greatly increases your Shotgun usability

ENDURANCE

[5 POINTS]

Your limb damage is completely eliminated

You gain much-increased benefit from being Well Fed or Well Hydrated

Endurance increases your maximum Health and allows you to use a bunch of useful defensive Perks. You could also consider using Ironclad instead of the two Perks listed above

CHARISMA

[7 POINTS]

When adventuring alone, take 20% less damage and gain 30% AP regen

Reduce your target's damage output by 30% for 2 seconds after you attack

Charisma is mainly related to team play, but it also has several useful Perks for solo players. The two Perks combined are mandatory for this build

INTELLIGENCE

[5 POINTS]

Your explosives do +100% damage

Intelligence is related to crafting and Power Armors. We do not intend to use any of that, but picking up Demolition Expert will greatly increase your damage

AGILITY

[12 POINTS]

Action Points regenerate 45% faster

Your shotguns gain a 15% stagger chance and a 30% chance to cripple a limb

Avoid 30% of incoming damage at the cost of 30 Action Points per hit

Each AGI point adds +2 Damage and Energy Resist (max 30) when not using Power Armor

Gain +6% (max 36%) damage for 30s per kill. Duration refreshes with kills

Agility increases your maximum AP and AP regeneration. It also has useful defensive Perks for non-Power Armor users and Adrenaline which is one of the best DPS-oriented Perk in the game for one point

LUCK

[6 POINTS]

While below 30% health, gain a 45% chance to avoid damage

Carry junk to gain up to 30 Damage and Energy Resistance while not wearing a Power Armor

Luck is used for two very valuable defensive Perks - Serendipity and Junk Shield

ARMOR: There are no strict requirements for armors in this build. It's a bit more important to get the right Legendary powers on them which will grant additional defensive stats. For example, Vanguard's, Bolstering, Cavalier's prefixes are extremely good 

WEAPON: Combat Shotgun is a fast and reliable weapon. You can easily find it at level 20 and then add modifications as your progress in the game

CHEMS: Psychobuff (+25% damage, +3 Strength, +3 Endurance,  and+65 to maximum Life) and Bufftats (Strength +3, Endurance +3, Perception +3, and increase your maximum Health by 40) are the best Chems you can use when facing powerful enemies. They both grant very good bonuses to your defenses which are this builds' weakest point. Remember not to use any Chems when you have the Healing Factor mutation

There aren't many mutations that you should forcefully look for. If you do manage one of the mutations listed below you can simply try to limit the number of Rad-Aways you consume and they will grant nice bonuses for quite a while

1. Healing Factor - grants insane Health regeneration bonus at the cost of having reduced Chems effect on you
2. Speed Demon - increases your movement speed and reload time, however, requires you to drink and eat much more frequently