You might use these and immediately think the recoil is totally uncontrollable - but there's a secret interaction available here I've noticed: the recoil can be controlled no problem if your other weapon is also from the automatic artillery artillery category or the CC piercer category (tested so far). After the initial spinup + fire, pulse fire briefly to bring the recoil under control, and then you can control it without much more recoil that the gatling guns! I'm not 100% sure but it seems like strafing left or right (either) seems to help bring the recoil under control. After it's under control you can even boost jump and retain excellent recoil control - use that time to wipe out encroaching enemies or simply shoot straight down to melt anything you jump over.

These weapons deal absolutely face melting amounts of damage and they seem to infinitely pierce targets out to their maximum range - once you get the hang of this you can just kinda wave the death-stream around and wipe stuff out. The highest level FR can even stagger-lock the mighty Erginus; the damage of these things is truly crazy!

If you have enough momentum (such as from dashing), many weapons let you slide across the ground while attacking. Depending on how fast you get going, this can be used as a form of evasion while you attack simultaneously, and you can dodge a lot of incoming damage this way. My personal favorite is a CC piercer + a Cannon Shot: you can zip and slide around mobs dishing out crowd-mulching shotgun blasts.

An interesting thing about Air Raider's Guide equipment is that it lets you lock multiple missiles onto the same target - when normally you can't do that. This works with any Fencer Missile Launchers that fire multiple missiles. Air Raiders can use this to spread out a lot of beacons to kill several targets, or focus all the damage onto one.

Many Fencer weapons have large enough ammo capacity that you can time one weapon to reload while the other has yet to run out. Once you get the pattern established, just hold both fire buttons down and don't let go. The result is an endless wall of damage. This doesn't deal as much raw damage as firing both weapons as fast as possible, but this strategy is really useful for locking down a horde or any tough enemy that can be staggered (which is most of them). Just make sure you keep an eye on your radar so you aren't flanked. My personal favorite pair are the automatic shotguns, but there are many possibilities.

Many mob-type enemies dish out way more damage than they can take - especially spiders. It's kind of situational, but you can totally equip two shields. Especially with two reflector type shields, you can almost create a reflective wall that kills anything shooting at it. Bug Invasion is a great mission to see this in action on higher difficulties.