the 3 armours are kinda equal in this game
leather best against energy
metal best against ballistic
combat best all round against both ballistic and energy (but not as good as leather or metal against their specialised DR)
synth armour is technically the best all round (not normal comabt is better at normal, but sturdy and heavy its the best)
but you can only find it actually on synths not as loot (except legendary) or to buy (except instuitute)
all armour is massively outshined by ballistic weave though
for all situations, ballistic weave + combat would be the best setup
mods well best you can get at lvl protection mods obviously but the misc mod slot well thats all about your play style
for weapons +damage perk (rifleman, commando etc) trumps actual weapons by a long shot. also playstyle means everything for which ones are better
there is very very little weapon selection in this game so am unsure when you say best if you actually mean mods and/or legendary effect/unique?
but IMO
best sniper = overseers guardian
best CQB = deliverer
dont use melee nor lasers, but im pretty partial to the swords (just cause i like swords)
as far as you 55 damage sniper rifle goes, do you have the best mods for your level?, have you kept gun nut up with your level? or using higher level found mods on it? do you have rifleman perk at your level? or have it at all?
in this game weapon damage is completely irrelevant as you get higher level unless you keep up with the appropriate perk (eg rifleman for all rifles ballistic and laser and shotguns. commando for all auto weapons that arent in the heavy class etc)