Shotgunners have the quickest fire rate of a unit, which is key to using them to your advantage.
If they're within range of another unit, say a Machine Gunner, they will get their shot off first and win the battle (but you also need to take into account the other factors that determine the winner: cover, are you moving, are you switching stance, and are you aiming).
As much as I hate camping, they're nice to camp a doorway and cut down anything that walks through it, or walks by a window they're camping.
And like it was mentioned above
, they are the quickest unit, so if you're having trouble with a sniper, they should be your go-to unit, if you have any.
gaming.stackexchange.com/users/10083/turkeyandcheese
there are great for indoor use.
also if you have them wait around a door that you know some one will pass through.
they also walk the quickest of any unit.
(well at lest in the last version i played in depth)
gaming.stackexchange.com/users/9835/TrewTzu
Shotgunners are only useful at close range, this is the most important part.
They are nearly unbeatable at close range (baring factors like cover and etc).
I find the most effective thing to do with them is to guard doors that the enemy is likely to enter and also to rush and flank the enemy.
You might need to force your shotgunners to ignore enemies or 'continue on sight' in order to rush the enemy.
If you're not running directly at any enemy, there's a good chance they won't be able to get a good shot off and you can get up close and at that point the shotgunner is probably going to win.
gaming.stackexchange.com/users/6277/Chris Rasys
Here's a simple tip for reducing the problem of limited range that the shotgun unit has.
In dark mode, you are often uncertain if an enemy unit is approaching of moving away from your position.
Aim your shotgun unit just before it passes through the door opening, move out a slight bit, cancel aim, then move back in behind the wall.
If an enemy is approaching your position and is close, your shotgun will get a shot off.
If the enemy is moving away, you will only be exposed for a very short while, not allowing machine guns to fire before you are behind cover.
Even if you do not get a kill in this case you should be safe, and peeking like this still gains you valuable information in dark mode about your enemy's position.
gaming.stackexchange.com/users/10868/Kristian Sørensen
Use walls.
It's very important to block LOS of your enemy with full wall.
this is the best way of killing enemy machine gunners in CQB - rush to the corner, then jump from there and shoot.
Even if MG is behind cover, if he's close enough, you'll win.
gaming.stackexchange.com/users/13225/aedrill
I just got Frozen Synapse, and I'm having a hard time making good use of the shotgun units.  It seems like they often just have too short of a range to compete with the other units.  What are some basic tips for getting the most of out them?
Tips for using shotgun units effectively
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gaming.stackexchange.com/questions/23450
gaming.stackexchange.com/users/455/TM.
Shotgunners have the quickest fire rate and are great for indoor use at close range. The most effective way of using the shotgun units are for defence due to their speed.
Great for creating defence walls. Speed is also an advantage.