I've made excel analysis on weapons of DoomRL.
On burst type weapons,
Hyperblaster + Trigerhappy 2 + Firestorm pack is the ultimate weapon.
(As BFG 10K is extremely rare and its splash is dangerous for you, too)
Even with Eagle Eye 5, Burst minigun cannot catch up F-modded hyperblaster.
And since Ammochain build BLOCKS eagle eye, the best assembly for minigun would be definitely assault rifle.
Burst laser rifle is quite cool, too.
If you are not going with Ammochain build,
nanomachic laser rifle would be the best.
On Army of the Dead build, Jackhammer is the best, Super shotgun(P) is second.
On Shottyhead build, Nano super shotgun(P) is arguably best, as it does not need reload.
Otherwise,
Plasmatic super shotgun+P > Super shotgun+PP > Jackhammer > Focused double shotgun+P > etc.
Plasma shotgun is lot much better than tactical/assault shotgun.
Since plasmatic ssg, normal ssg needs reload after each shots,
overall performance of plasma shotgun would not that worse than SSG families.
Melee weapon is simple; Dragonslayer is absolutely the best (with its permanent berserk effect)
and on Brute level 3, Azrael's Scythe > Longinus Spear > ripper(T) (due to its low accuracy),
however, on Brute level 5, ripper(T) is second best one (first is DS, of course)
On pistol weapons,
Storm bolter combat pistol (P) gives the best performance on sharpshooter build
(considering the reload time of Grammaton Cleric Beretta full-auto mode),
and Anti-Freak Jackal/High power combat pistol would be best combination for Gun Kata build.