[Sabato Kuroi]

Since our rigger is specialized in ballistic weapons she needs a good heavy weapon for her Steel Lynx
There is no availiability issue, she is not a starting character (though her ability to actually get her hands on weapons with really high availiability is another matter)

The Lynx has a decent ammount of recoil compensation but she has somewhere around 15-16 dicepool while jumped in and I don't know if she can handle full auto.

What do you think?

[Rift_0f_Bladz]

Suppressing fire doesn't have to worry about recoil at all. Also, many of the auto cannons are either SS or SA, so recoil is not as big of a deal. Plus, one simple action each pass resets the recoil anyways. With 500 rounds for a heavy weapon mount, the 20 rounds for suppressing fire is not really a big deal.

[Sabato Kuroi]

Well, suppresive fire is a nice tactic for drones but Steel Lynx should be able to contribute more than that in a fight

I'm also leaning towards  cannons instead of  machine guns

Ares Thunderstruck gauss rifle is strong but seems expensive (and uses energy  packs as well as regular ammo)

[Herr Brackhaus]

For heavy bang-for-your-buck, the Ruhrmetall SF-20 is pretty decent at throwing hot lead downrange, what with it's 12P AP-4 stats. It's expensive, though, at 20k and 18F availability; the steel lynx is not exactly invincible, so I'd be cautious about outfitting such an expensive weapon on a relatively fragile drone.

A better choice to my mind would be the Cavalier Arms Crokett EBR; versatility of SA and BF, 20 round clip, same DV and AP-3, but for half the price. It's not going to do much good in terms of suppressive fire (unless your GM rules that it can be mounted with a belt-feed, which makes it a superior option in almost every way), but it's a decent choice regardless in my opinion.

If you still want to go heavy weapon but want to shell out a little less than 20k, The RPK HMG and Ultamax HMG-2 both come in at around 20k with similar stats. The most cost-effective machinegun out there is undoubtedly the Krime Wave; at only 2000¥ it's a bargain for it's FA, 10P AP-2 stats.

EDIT:
For cannons, I would go with the Krime Cannon 9 times out of 10. It's "only" 21k, sports SA mode (which allows for SA Burst), and only has one less DV than the twice as expensive Panther XXL. With all cannons you might run into problems with ammo, though, unless your GM allows it to be belt-fed (I wouldn't).

[Rift_0f_Bladz]

Heavy weapon mount is normally belt fed (it is in its description in the core).

[Herr Brackhaus]

Not to start anything, but that's a bit of an assumption, Rift_0f_Bladz. Neither weapon mounts really specify if they change the weapon feeding mechanism, merely that they can hold up to x rounds.

From SR5 page 461 (emphasis mine):
"Standard weapon mounts may hold any assault rifle or smaller-sized weapon and 250 rounds of ammo. Heavy weapon mounts count as two weapon mounts and can hold any weapon and up to 500 rounds of belted ammo or up to Body rockets/missiles."

The mounts ability to hold ammunition does not necessarily translate into being able to use belted ammo with a clip-fed weapon. This topic seems to have been the source of quite a lot of debate on this forum, so it's definitely a GM call at this point in time. I'd argue that one of the most significant benefits of machineguns over assault rifles are range and the ability to use belted ammunition; take away the belted ammunition part and some might argue that there is no reason to use machine guns over assault rifles at all. Not being able to use belted ammunition does bring up the issue of "how does a drone reload it's non-belted weapon", though.

[Namikaze]

I'd go with lasers.  Because lasers are cool.

[Herr Brackhaus]

I'd go with lasers.  Because lasers are cool.

I'd argue that lasers do not, in fact, have an inherent temperature since they are composed of photons, but that'd reveal just how geeky I am

They do, however, have potential... See what I did there?

[Ursus Maior]

A laser will indeed crack most opposition wide open. The Archon will deliver precision firepower at extreme ranges (sniper table) and reload everytime the drone is plugged into your mothership's powergrid. As a semi-automatic weapon, you can fire short bursts and don't have to care for recoil.

Another option might be a flame thrower. But actually that's nasty stuff and might blow back in your face in multiple ways. Quite literally, because the drone can get shot and explode and secondly this might give your tea, notoriety. While small, fast drones with crazy weapons are good for shock and awe, a flamethrower is such a horrible weapon, someone might put a prize on your head.

[Csjarrat]

Lasers or the thunderstruck are a great call, they can plug into the drones power unit to avoid the whole reloading/power pack issue too.
I'd probably want to stick a second weapon on it for extra functionality, be that under barrel or on an extra weapon mount.
Something like a GL to lay down tear gas/neuro stun or some other non-lethal or support weaponry (sonic rifle) would be a great addition, because you don't always want to punch holes through stuff or slice it in half with a laser.
You don't lose anything by using exotic/rare weapons on drones as they all use gunnery skill or autosofts.
If she prefers the more conventional route then stick an LMG on it. Gas vent 3, smart gun (top), underbarrel gl and 500 rounds of whatever to feed from. The huge amount of belted ammo is the seller for that load out because ARs otherwise would be the better choice for the money, but you def don't want your expensive drone running out of ammo in the middle of a firefight with no way to reload it!

[Ursus Maior]

Plus the high amount of available ammo makes long bursts an alternative in terms of destructive power when compared to enhanced ammo types like APDS and ex-explosive. That keeps costs down and enhances availability. Of course, once available, a laser will hardly run out of ammo and never increase your ammo bill again. At AP 10 and Acc 7 (plus smartgun) that will slice every enemy into pieces.

A non-lethal option remains an obligative second choice, though. There are days, when you must not kill. And lasers don't do well in that department.

[Herr Brackhaus]

Called Shot: Eyes do just fine for non-lethal

I think Lasers should get a bonus when used against the eyes, personally. Make Blindness last longer, or something.

[Csjarrat]

Lol, a laser would ablate eye tissue just as well as any other tissue. Blindness from lasers would only be fixable with cyber eyes and extensive reconstructive surgery!

[Namikaze]

I'd go with lasers.  Because lasers are cool.

I'd argue that lasers do not, in fact, have an inherent temperature since they are composed of photons, but that'd reveal just how geeky I am

They do, however, have potential... See what I did there?

*GROAN!!!!!*

[Rift_0f_Bladz]

Herr Brackhaus, I understand the whole how do drones reload, but as you quoted, I said heavy weapon mount. Which as you lovely bolded for all of us, says belted ammo in the core rules. And concerdering there are modern weapon mods to convert AR-15 and other assault style weapons into a belt fed weapon, I see no reason not to allow any simi-auto + mode gun to be allowed to use a belt fed system in a heavy mount weapon system. Does that mean the weapon could be removed and quickly used, most likely not.

As for best heavy armor buster in a drone, the laser weapons have some of the nicest AP currently in the game, at least in ideal conditions.