The june update was largely perfect as far as the primary weapons go. I'll kind of gloss over those.
Battle rifle: It's an excellent gun now. It's overused, but not unbalanced. Relatively short range balances its high power.
DMR: It retains its niche as the most versatile primary on offer. It can do anything, but it gets beat by the other primaries inside their respective domains. Good for people who like to do everything!
Covenant Carbine: Its superior accuracy gives it an edge on the battle rifle at long range, and its high DPS gives it an edge on the DMR at close range. The most difficult to use, but almost as versatile as the DMR. My favorite primary! Maybe consider changing that reload time, but it's not a big issue.
Light Rifle: My go-to gun on big maps! Very tough to use outside its niche (dat hipfire), but punishingly powerful inside it. Perfectly balanced.
Assault Rifle: Give yourself a big, sloppy kiss and a high five for this one. My beautious, blat-a-gat-ing assault rifle is actually competitive now! The pre-patch iteration was usable, but now I feel I'm actually at an advantage when I use it in close quarters. Thank you, thank you, thank you.
Storm Rifle: Still not quite as useful as it could be. The assault rifle is clearly superior (hitscan, woo!), so maybe consider reducing shots needed to break shields and increasing shots needed to kill health, keeping overall shots to kill the same. It'd be great for teamshotting when your buddy has a precision gun, and it'd be more faithful to previous plasma rifles.
Suppressor: I don't use this gun. Can't give any feedback.
Magnum: Awesome. Don't change it.
Boltshot: Maybe consider making the primary fire a 10 shot kill, instead of an 11 shot. Not being able to kill someone in one magazine rustles my jimmies.
Plasma pistol: As a dedicated vehicle driver, I know how annoying the overcharge is. I don't, though, think it's fundamentally unbalanced. I have one critical issue though. Consider the following:
I'm in a mantis/scorpion/wraith. Someone EMPs me.
They then repeatedly EMP me while walking toward me. I sit unable to move for 10 seconds or more. They board and kill me! Wheelman doesn't resolve this issue, because the plasma pistol can fire overcharged shots too quickly. Consider increasing the overheat duration or something similar to resolve this.
Also make the primary fire a little better? It is kind of terrible.
Beam Rifle: This gun is still just a little bit too delicious. Maybe consider increasing heat per shot to lower the sustained fire rate? I feel like the gun doesn't punish a quick second shot enough.
Concussion Rifle: This gun is, like, not good. I find it actually hard to get kills with it. A perfect fix would be to significantly increase projectile speed.
Spartan Laser: Sometimes, when using this gun against infantry, I get hitmarkers. This is not okay. More infantry damage! (Please.)
SAW: This gun rocks my socks. Maybe too much. Give it less starting ammo please? I don't like seeing someone (even myself, as has happened on occasion) using this gun to fuel a Frenzy.
Rocket Launcher: Please consider reducing maximum ammunition to 6. 8 is just... Too much boom.
Incineration Cannon: Similar issue! Maximum ammo should be 4 or 5.
Plasma Grenade: Again, as a vehicle pilot, I used to have serious issues with these, but Survivor has calmed me down. Maybe make it a require three grenades to kill a warthog though? One person should not be able to take down a warthog so easily.
Pulse Grenade: Consider either increasing its effectiveness or giving people 2 to start. An interesting idea might be to add an EMP effect to it, to give people an anti-vehicle option that isn't a plasma grenade.
You might even transfer the plasma pistol's EMP ability to the pulse grenade, to make vehicle take downs require more teamwork!
The vehicle firepower is at a perfect spot right now, the only issue being the warthog's cardboard construction. I cannot emphasize enough my satisfaction with the Survivor ability. When I'm in my glorious mantis (may it live forever! [But seriously though, Halo for Xbox One... Keep the mantis]) and my stompy robot rampage is ended by some chumps swarming me... It isn't ended!