The Heavy Gunner com is a stable choice for many Roland players. It offers some of the best gun buffs available to Roland and with the exception of Impact only effecting bullets, these buffs apply to every weapon, giving practically complete freedom in choosing your loadout. The gun buffs are so good, that the Heavy Gunner com can even give more specialized offensive coms like Commando and Rifleman a run for their money even with the weapons those coms are meant for.
The Pros:
-Massive buffs to guns
-Buffs are universal, giving unmatched freedom in weapon selection
-Highest magazine size buffs in the game (barring Wide Load and RLs w/ small mag sizes), and potentially highest fire rate buffs (w/ mat2 version, only mord w/ pistols can get higher fire rate buffs)
The Cons:
-No defensive buffs
-No turret buffs
-Limited damage buffs with massive fire rate and magazine size buffs = ammo hungry
The build:
http://talent.87bazillion.com/soldier.php?505505050505005050055
You will notice that this build has 13 unassigned points, that’s because the last 13 points can be put pretty much wherever you want, although there are some notable choices:
-Refire and Deploy: One or even both of these can be a good idea to allow for frequent turret use, which can go especially well with Aid Station (if you don’t mind staying near your turret) and Supply Drop (which can help take the edge off of ammo use particularly when running mat2 versions of the com).
-Sentry and Guided Missile: These are good if you want the turret to help dish out some punishment.
-Supply Drop: This is highly recommended to be at atleast 3/5, this will keep your ammo pools from running out, and can also resupply you if you suddenly find yourself out of ammo at a bad time.
-Aid Station: This can work great with higher accuracy weapons, and against enemies that will bum rush you, the health regen is quite potent, and stacks with Stat’s regen so you can end up regenerating 10% of max hp per second, that on top of Quick Charge can make it VERY hard for the enemy to put you into FFYL.
-Cauterize and Revive: These are useless to the solo player, but are quite handy in coop.
Main skills: The Why:
Infantry Tree: 20 points
-Impact: More damage with bullets and it’s buffed by the com, definitely 5/5 this!
-Scattershot: For when we break out our Shotguns.
-Metal Storm: It’s on the com, and gives a substantial fire rate buff on kill and some recoil reduction as well, definitely worth 5/5.
-Assault: For when we break out our Combat Rifles (including Machine Guns)
Support Tree: 15 points
-Defense: Not actually all that powerful on its own, but it’s far better than Stockpile. It increases the our Shield Recharge rate. Note that this does not effect shields regenerated by any means other than the natural recharge mechanic, in particular, Quick Charge’s rate of regeneration is unaffected.
-Quick Charge: One of Roland’s best skills in his entire skill tree. The on-kill shield regeneration will make it very difficult for enemies to break our shields.
-Grenadier: Not only does this skill help supply us with plenty of grenades to throw, but the damage buff affects not just grenades, but rockets as well!
Medic Tree: 20 points
-Fitness: More health? Yes please.
-Overload: It’s buffed by the com and already one Roland’s best skills, huge magazine sizes = more shooting = more killing.
-Grit: Nice to have some damage mitigation versus bullets, although it’s not much, every bit helps, and this is also a useful stepping stone to Stat.
-Stat: On-kill health regeneration to us and our nearby friends? Sign me up!
Weapons:
Given that nearly all of the coms buffs apply to every single weapon in the game (only things that don’t fire bullets are missing out, and only on the boost from Impact, which isn’t that much really), weapons are pretty much a matter use what you want (or what you have). So for the most part, weapon selection is a matter of user preference. That said, keep in mind, that our damage buffs are dwarfed by our magazine size and fire rate buffs (the latter is especially true if we’re running the mat2 version of the com with it’s +65% Weapon Fire Rate 5th line), so we have a slight bias for weapons which have above par damage and above par reload speeds for their type.
Shield:
As Quick Charge’s shield regeneration scales with your maximum shield capacity, Roland has a natural preference for high capacity shields. As such, the ideal shield for this build is a perfect parts level 68 Pangolin Ironclad shield which has 3547 capacity, the next best would be a purple level 69 PNG2-550 Impenetrable Fortified Shield which has a capacity of 3413. A good alternative would be a Torgue Muscleman of the same parts as the health regeneration of Stat (and if chosen w/ remaining 13 points, Aid Station as well) scales with maximum Health. Against enemies that deal almost exclusively Shock/Fire/Corrosive damage, a Cationic/Endothermic/Hazmat (respectively) shield of those same parts would be a good choice as well given the significant damage mitigation such a shield provides against damage of the applicable element.
Grenade Mod:
Just as with guns, grenade mod choice is all about user preference. With 5/5 in Grenadier, we will have plenty of Grenades to throw (even more if Supply Drop is taken as it also regenerates Grenades).
Mat2 or Mat3?:
The mat2 version boast an impressive +65% Weapon Fire Rate bonus which works with any weapon you can hold and surprisingly also affect the bow gun of vehicles when you’re in the driver’s seat (not sure about other weapons in applicable seats). The mat3 version offers +42% Weapon Damage, which is particularly valuable in light of the fact that most of Roland’s DPS buffing skills don’t buff weapon damage, meaning his only buff to Weapon Damage is from weapon proficiency (unless using shotguns, then Scattershot’s damage buff is also weapon damage), it also seems to be much rarer than it’s mat2 counterpart, at least in my experience. Given the already impressive Fire Rate buff from Metal Storm (which is buffed by the com) and massive magazine Size buffs from Overload (which is also buffed by the com) and the impressive +80% Weapon Magazine Size 1st line effect and lack of reload speed buffs, the +42% Weapon Damage effect is usually actually more valuable than the +65% Weapon Fire Rate buff in spite of the number advantage, it also helps limit the ammo hungry nature of the build some. Thus I generally recommend running the mat3 version when available, though the mat2 is very useful for weapons with mediocre fire rates, especially Jakobs weapons.
General tips and other information:
Given the completely weapon type freedom of this build, it supports virtually any playstyle desired. The ammo hungry tendency can easily be offset by running weapons that use different ammo types thus spreading out demand across your various ammo pools and since Supply Drop replenishes all of your ammo pools, it can completely negate any ammo issues you might otherwise encounter. Roland is very capable of sustain tanking thanks to Quick Charge and Stat (and even Aid Station too if you choose to run that), all that need to do is keep getting kills to keep the regeneration going, which given this build’s considerable offensive buffs, is generally easy to do. Though some ‘boss’ fights don’t offer any easy targets to pick off and get the regeneration going/continue it. Those are usually the most challenging fights for Roland as he only has Fitness’s mere +25% to maximum Health increasing his total hit points, and this is yet another reason to like high capacity shields on Roland, they buy you more time to get a kill before you’ll take a knee. Aid Station can help in these situations as well since that depends only on having your turret available. The Scorpio Turret is also very useful as a distraction, since it will likely draw a fair amount of aggro which can be used in a number of ways by the tactically minded player, from simply drawing fire, to distracting the enemy while you flank them.
It’s just good knowing what weapons to use when you follow builds. I understand you can use ANYTHING, this just eases my mind is all 
A bit silly I know but…it just does lol.