The answer is simple and well known one; check who are their enemies and kill them all! Ur enemies' enemy is your friend, and opposite. when ur as natural with them, check the stations or whereelse for hackers to give money and be friendly with them if you have enough money ofcourse.OR..just kill them all and get their weapons.

-NO PAIN NO GAIN-

There is at least one shipwreck that drops Skyblast B guns.

I did this.

During sp, I worked my but off trying to reamin as close to neutral to all the factions I could. As a matter of fact, I found out (at least for myself) that is best to remain friends with the Junkers as well as possible at the end of the SP. After your factions change when you complete the sp game, go almost directally "north" (at least according to your star map) to the junker base above Manhatten. Look at the job board. You should be able to get jobs fighting Xeno's. I did this, and I literally only had to do one job, and I was at least neutral to all factions, except the Xeno's. (I was barely neutral to some, but as long as I only shoot Xeno's, I should be ok.) Now, I can just go exploring, and not have to worry about anyone attacking me but them. and THEY are just sad.

just go around shooting xenos, dont take missions

The reason I took the missions, was that for some reason, if you are on a mission, the other factions ignor you. If you have no need to blow away one of the factions that you want to build your friendship with, it goes better for you.

wow i didnt know there was a wreck that dropped those guns, ive gone through like 21 wrecks so far and havent found them

hy, u can find it when searching "the Honschu Maro" and escort, the are gmg ship
fire at the wreaks, and get it, good luck

To clarify: at the wreck of the Hosho Maru in Omicron Beta, one of the wrecked escort ships has 2 SkyBlast B guns. To get a SkyBlast Turret B, however, you'll need to be quite friendly with the GMG.

The way I make GMG friendly is by doing jobs for them.

I only take Outcast jobs for GMG.. And I try to select jobs that require the least amount of killing. I don't want the Outcasts to become hostile.. So when I do the GMG jobs I avoid killing the Outcasts. I will usually just bring them down to "Barely functioning here" then I will select a new target..

Once GMG is neutral enough to work for.. You only have to do about four jobs for them before the SkyBlaster is offered.

Or you can do missions for the Outcasts at Ruiz Base in Omicron Beta and the GMG Eagles will drop Skyblast B cannons and Skyblast B turrets for you. This is how I usually get them, as building your rep up with the GMG negatively affects Rheinland, all of the border world pirates, and I think the Kusari criminals as well.