Say good bye to your crit damage and knockdown chance if you start using slugs which makes the shotgun strictly inferior to the tri-beam in pretty much every way.
Aaaaaaand we finally got to the point I wanted,even using Slug Rounds,the tri beam is still inferior when we look at the Riot Shotgun.
A Tri Beam Laser Rifle,with all the modfications and perks can reach a 335.2 DPS,while the superior riot shotgun can reach 442.7 DPS,funny no?
Also the Tri Beam Laser rifle can only use 3 types of Ammo,and their effect only vary on damage and CND,now you can easily say Max Charges make the Tri Beam Laser more powerful than the Riot Shotgun,but you are awesomely wrong,the dps will be higher,reaching something like 480,but the CND will decrease 2.5,this with the crappy Hp from the Tri Beam Laser will make it break after shoting 50 to 80 rounds,I would also like to remimd you that the Coin Shot Ammo from the Shotgun has a 1.3 damage multiplier,which makes the Riot Shotgun pack almost 600 DPS with it,funny right?The AP use for the Riot Shotgun is 5 points lower,meaning it can,with all the perks,shot over 10 shots in vats,and the variation of 12 Gauge Slugs make it's awesomeness to increase even more,Dragon Breath Shells do Fire Damage,the one that is increase by 50% when used with the Pyromaniac Perk,so on the 0.9 Damage Multiplier is transformed into a 1.45 Multiplier + Fire damage,Pulse Slugs also mean that robots and power armor aren't a problem anymore,where your tri beam Laser would probaly break before killing a Power Armor foe,also,Bean Bag Rounds are extremely useful when using REALLY powerful enemies,by simply knocking them down you can exterminate even the mighty legendary Deathclaw.The Tri Beam Laser Rifle is perfertly usable but weapons like Elijah's advanced LAER and YCS-186 easily outstand it when it comes for weapons using Microfusion Cells.