Assault Rifle has more... fire power. AR is so filled with goodness, you should be selective with your secondary.
The cream of the crop are: Ring of Fire, Fire Sword Circle, Build Up, and Hot Feet. Anything other than those four will have to be taken as the opportunity arises due to your own personal preference. In my opinion every Assault Rifle power except Snipe is preferable to Combustion, Blazing Aura, Burn, or Fire Sword.
The worst AR powers, to me, are Snipe, Ignite, and M30 Grenade. So swap those in and out with your favorite fire powers just to mix and match.
You don't need Combustion. AR provides plenty of AoE, all of it superior to, and easier to use than, Combustion.
The difference between a solo and team build is minimal. For a solo build, take Beanbag; for a team build, don't bother with it. Get more damage instead.
Some people consider the single target damage of AR kind of weak, and would recommend supplementing it with Fire Sword, but to me Fire Sword winds up starved for slots, since everything else tends to have a higher priority. Burst, for example, might seem weak, but it can be used when mezzed and at range, both decisive advantages over Fire Sword, IMO.
Edit: I forgot to mention Consume. It's crap. It's not good enough to allow you to forgo Stamina, because its recharge time is penalized out of proportion with the minimal damage it does. It requires all six slots to even approach the efficacy of Stamina, and that's assuming you're provided with optimal situations for its use. With no endurance crashing nuke, you have virtually no reason to take Consume.
AR/Fire is a build that lends itself to teams, just because of the awesome AoE potential. Solo, it also has a lot to offer, its just that it feels a shame to lose out on its teaming potential.
Going solo, it might be fun to play more of a ranger. The following is an idea I have for a 2nd build on my AR/Fire. Utilizing Aid Self between spawns should allow for very speedy play (it works well on my Arch/Fire and En/Dev blasters).
Hero Plan by Mids' Hero Designer 1.401
http://www.cohplanner.com/
Click this DataLink to open the build!
Solo AR-Fire: Level 37 Science Blaster
Primary Power Set: Assault Rifle
Secondary Power Set: Fire Manipulation
Power Pool: Fitness
Power Pool: Speed
Power Pool: Medicine
Power Pool: Leaping
Hero Profile:
Level 1: Burst -- Acc(A), Dmg(3), Dmg(9), Dmg(17), RechRdx(23)
Level 1: Ring of Fire -- Acc(A), Dmg(13), Dmg(13), Dmg(17), RechRdx(34)
Level 2: Slug -- Acc(A), Dmg(3), Dmg(5), Dmg(15), RechRdx(23)
Level 4: Fire Sword -- Acc(A), Dmg(5), Dmg(7), Dmg(7), RechRdx(25)
Level 6: Hurdle -- Jump(A)
Level 8: Beanbag -- Acc(A), Acc(9)
Level 10: Buckshot -- Acc(A), Dmg(11), Dmg(11), Dmg(15), RechRdx(25)
Level 12: Hasten -- RechRdx(A), RechRdx(36), RechRdx(36)
Level 14: Health -- Heal(A)
Level 16: Build Up -- RechRdx(A), RechRdx(36), RechRdx(37)
Level 18: Flamethrower -- Acc(A), Dmg(19), Dmg(19), Dmg(29), RechRdx(31)
Level 20: Stamina -- EndMod(A), EndMod(21), EndMod(21)
Level 22: Super Speed -- Run(A)
Level 24: Stimulant -- IntRdx(A)
Level 26: Ignite -- Acc(A), Dmg(27), Dmg(27), Empty(37), Empty(37)
Level 28: Consume -- Acc(A), RechRdx(29)
Level 30: Aid Self -- Heal(A), Heal(31), RechRdx(31)
Level 32: Full Auto -- Acc(A), Dmg(33), Dmg(33), Dmg(33), RechRdx(34), RechRdx(34)
Level 35: Combat Jumping -- Empty(A)
Level 38: [Empty]
Level 41: [Empty]
Level 44: [Empty]
Level 47: [Empty]
Level 49: [Empty]
------------
Level 1: Brawl -- Empty(A)
Level 1: Sprint -- Empty(A)
Level 2: Rest -- Empty(A)
Level 1: Defiance
Why Blasters? Empathy Sucks.
So, you want to be Mental?
What the hell? Let's buff defenders.
Tactics are for those who do not have a big enough hammer. Wisdom is knowing how big your hammer is.
For the record I prefer Flight for my travel power.
I've never considered dropping Stamina with Consume, I generally use it to top off my end but don't rely on it by any means.
I usually use Burst, Slug and Buckshot for my single-target ranged attack chain. I know the latter is a cone but it's not that much of a cone, and they seem to come together pretty well.
I might drop M30 Grenade, it seems to do pretty poor damage for an AoE and I already have enough of those that need slots. I wanna keep Fire Sword, I like using it as a finisher, and I love Ignite on teams.
Just adding my preferences, but I'm gonna try Aid Self later.
Help! My AR/Fire is 38 and after several respecs I still can't decide on what powers I want. I'm less troubled on the AR side, I dropped the snipe and got Bean Bag but dropped that too, but the real issue's on the Fire side.
Do I need both Fire Sword Circle and Combustion?
Both Hot Feet and Blazing Aura? And do I need Consume to keep them going?
Yes, I took both Ignite and Burn and find having basically the same power more readily available to be very handy.
And how would I go about making a solo-oriented second build?
Help me people, please.