Kagoshima Depot in Kyushu (run by the Farmer's Alliance, IIRC)

Thanks for the tip, I finally tracked down that base and bought about 4 class 5 Vultures and 6 class 6 Vultures.I had to bribe the farmers to get a good enough rep to purchase the LV6 Vultures. I'm working my way through the SP the second time around with the Drake light fighter. I've found that 2 class 5's and two class 6 Vultures on this ship packs a huge punch and you can maintain constant firing for 31-32 seconds because these weapons are so energy efficient. So far this configuration has let me take out a couple of Kusari gunboats with energy to spare. I'm going to load up the Anubis with these for the last part, It should wreak havoc with 6 LV 5 Vultures. I'll probably have enough energy reserve left to get a LV 7 Angelito turret with a good replenish rate.

Correction- The Anubis would allow only 6-LV6 weapons and one turret. So I could put 6-LV6 Vultures in it, with the most power hungry,destructive, LV6 turret money can buy.

The Vultures have an efficiency of 6.00; they are the most energy-efficient weapons in the whole Sirius sector and as such they can make certain parts of the final SP campaign missions much easier. Compared to the Death's Hand guns (nice sounds, no?) they can do almost twice the damage to the target before the powerplant of the Anubis runs dry.

However, there are other guns easily available at that point in the campaign that also have decent efficiency, like the Reaper Mk II (Order) with 5.00 or the Rheinland Flamecurse Mk I with 4.80. The Bundschuh Luger is also nice for equipping the Anubis; efficiency is only 4.00 but it does 50% more damage than the Death's Hand and has very good speed/range (700/700). The GMG Sunblasts are also a very good choice for pulverizing Nomads.

Pretty much everything you can buy at that point in time is good enough to do the job. The only really important question is: what do you want to have fun?