I'm thinking about a special kind of fire gun use here : the cover fire.
When doing a cover fire, it's doesn't really matters if you actually fire bullets or not : if several full-auto guns are firing, no one will raise its head anyway.
So i wonder if it might be useful to have a gun that :
1) can fire real rounds -fair enough-, ...
2) but also fake rounds that only make the noise/flame/smoke/... of a real round.

The advantage being that you could have 3 (?4?) times more ammo in a magazine vs real rounds, and even probably a lighter magazine, thus increasing the operational capacity of those guns.

Edit : both magazine would be loaded at once, and round switch would be instantaneous. One way would be to have two triggers. Another rule : When fake ammo runs-out, firing will bring real ones.

Edit 2 ?? I wonder if we could agree about : such change wouldn't bring down the reliability of the gun ???

I understand very well that the enemy would soon know about such fake fire : but anyone using such weapon can, still, switch to real rounds at any time and kill an enemy suspecting a fake fire and leaving its cover : sound is still fearsome, the cover is still working.

Why isn't this kind of gun massively used ?

(i have no experience in weapons, i might be missing something obvious...)

  • $\begingroup$ Why is this question strangely colored? $\endgroup$ Mar 26, 2016 at 23:09
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    $\begingroup$ The OP admits to knowing nothing about guns, yet rejects the arguments or people who clearly know what they're talking about. Mind-blowing. My friend ... blanks are useless in a live engagement, and only likely to get your own men killed. Furthermore, the logistics complications, as well as the fact that your guns wouldn't work properly make it a really, really bad idea. Life is not a video game, alright? Listen to the smart people who were kind enough to post here. $\endgroup$
    – AndreiROM
    Mar 28, 2016 at 14:34
  • $\begingroup$ @AndreiROM: "The OP admits to knowing nothing about guns..." or actual combat situations! $\endgroup$
    – jamesqf
    Mar 29, 2016 at 19:03
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    $\begingroup$ How is this world building? $\endgroup$
    – RonJohn
    Sep 14, 2018 at 0:12
  • $\begingroup$ @GameAlchemist - re: Edit 2- I guess the question is whether this is a magic weapon. If it magically doesn't behave like real firearms, then sure, it could be reliable with the changes. If you want it to be like a real gun, then obviously people who know anything about weapons wouldn't agree with you that the modifications wouldn't impact reliability. $\endgroup$
    – jdunlop
    Sep 14, 2018 at 0:54

7 Answers 7


One thing I should correct you about is that using blanks does not increase the magazine capacity. Guns use rounds of very specific length, shape and diameter and even little variations in the ammo would lead to FTF (failure to feed) or FTE (failure to eject) issues which jam the firing mechanism.

Also, blank shots would not provide exactly the same sound and flash when used in a gun made for live ammunition. One variable of gunshot sound is the weight of the projectile leaving the barrel. With blanks, you don't get that singing "zoooooon" sound which is produced when a heavy, high velocity rifle bullet goes soaring in the air.

p.s. what would be the point of using blanks anyway when the cost difference between blank and live ammunition isn't much? (In fact, preparing high quality blanks might actually be more expensive than preparing live ammunition of the same caliber)?

Also, you would want to quickly switch a blanks magazine with a live ammo magazine in a gunfight and there would be a high probability that you pick up another blanks magazine in the heat of the battle.

... at least Hades would get a good laugh before judging your soul.

Edit To Add In Response To Comment By OP

You would want to redesign a whole array of different gun types (machine guns, assault rifles and SMGs come to mind and there are more than 60 total models you would want to redesign) to make them compatible with both types of ammo. And there is high probability this change would decrease the performance of those guns with live ammo. After all, guns these days are built for supreme accuracy with live ammo, any change, unless aimed for the same purpose, would be detrimental to the gun's performance.

"Furthermore, a counter-counter strategy would be to fire randomly real or fake rounds : this way sound is no longer an information."

Why would you want to randomly switch ammo when you can afford shooting live ammunition all the time? What is the advantage of spending 40 cents for a blank machinegun bullet when you can prepare a live ammo bullet of the same caliber in 32 cents?

Oh wait. This reminds me. Switching machinegun ammo boxes isn't as quick process as switching M4 or AK47 magazines. Why would anybody with a sane military mind want to waste 5-10 precious seconds switching machinegun ammo boxes for no incentive whatsoever? And then again, you would have an ammo box (which you unloaded) which is only half full and you have to remember exactly how much ammo is left is which ammo box.

The main question remains: what would be the advantage of all this hocus and pocus when manufacturing high quality blanks rounds is no cheaper than preparing live ammo rounds of the same caliber?

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    $\begingroup$ Was going to answer, but you said pretty much what I was thinking. Except: "If you have a real chance to hit, using real ammo is better, and if you don't, you are just adding background noise to already noisy environment." A system that mimics the sound of incoming artillery fire might be amusing though... Not useful, but amusing. The sound of approaching tanks might be fun too. $\endgroup$ Mar 26, 2016 at 22:28
  • $\begingroup$ I love the Hades laugh... :-) But in fact i assumed the cost of fake vs real is high (3-4) and that the issues that might be caused by having two ammo sources can be solved (weapon redesign). Furthermore, a counter-counter strategy would be to fire randomly real or fake rounds : this way sound is no longer an information. Enemies are deaf. I can't believe this couldn't be useful. $\endgroup$ Mar 26, 2016 at 22:30
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    $\begingroup$ @GameAlchemist Sadly, small-arms ammunition is pretty much only thing armies use that can be described as affordable. It is expected to be mostly wasted. Also the guns really do need to be as simple and fool-proof as possible. Otherwise they will break as soon as soldiers get their paws on them. And soldiers aside guns need to tolerate a wide variety of conditions. Maybe some kind of noise-maker under-barrel attachment would be possible, but soldiers would still prefer to carry real weapon instead. $\endgroup$ Mar 26, 2016 at 22:48
  • $\begingroup$ I completely understand your point, and find it valuable. However, i wonder if a fake X3 or X4 boost in ammo (more if you consider the ammo weight) in some special conditions wouldn't be a super-gift... ??? Again i'm thinking here about making the enemy deaf, which i (maybe wrongly) consider as an important move. $\endgroup$ Mar 26, 2016 at 22:52
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    $\begingroup$ So you are expecting to deafen the enemy sitting at 300 meters with your cover fire while expecting your own soldiers at 0 meters range to not get deafened by the confounding din they are making? Sounds more like magic than technology to me @GameAlchemist $\endgroup$ Mar 26, 2016 at 22:55

Even at quite close range, most bullets miss. See, for instance here.

As a result, particularly in military engagements, people don't react to the sound of guns being fired in the distance. Rather, they respond to the whir of bullets passing close by, or seeing dust kicked up by close misses.

Plus, I think you underestimate just how much stress is involved in shootouts, and how that affects (negatively) mental performance. Carrying a number of magazines loaded with blanks would be an open invitation to grabbing the wrong magazine and shooting blanks when you really, really didn't want to.

  • $\begingroup$ So you make a complete distinction of the theat a) that comes from hearing a (maybe near) gun firing and b) that comes from hearing a bullet passing near your (a 'crack' or dust explosing near you ?) $\endgroup$ Mar 26, 2016 at 22:14
  • $\begingroup$ PS : i don't think i underestimate the stress of hearing a gun shooting near : all the contrary ! I think that a gun that (can) just sounds as its shooting at you is enough a threat to be an effective tactical weapon for a cover fire !!! $\endgroup$ Mar 26, 2016 at 22:18
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    $\begingroup$ (Insert shaking of head/rolling of eyes) - No. The rule of a shooting environment is: if you can't hear the bullets, they aren't shooting at you, except at very close quarters, say 10 yards or less. Unless you can see them pointing their guns in your direction. And anyways, modern firearms have very little flash or smoke - that's why it's called smokeless powder. $\endgroup$ Mar 26, 2016 at 22:32
  • $\begingroup$ Well i'm not sure all soldiers would just consider a threat the 'second' sound of a gun. And i'd say a "less than 10 yards cover" seems quite a good way to sneak in to me... $\endgroup$ Mar 26, 2016 at 22:36
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    $\begingroup$ @GameAlchemist: I'd suggest that some practical experience would help here. $\endgroup$
    – jamesqf
    Mar 27, 2016 at 17:36

I think the detail that may be missing is just how fluid a combat situation is. When you are laying down cover fire, it's because one of your friends is out in a very precarious position, dependent on your ability to stop anyone from squeezing a shot off at them. If you were firing blanks for cover, you would have to do one more motion to switch to using real bullets if someone peeked out to take a shot at your friend. That's one more mechanical contraption between you and the protection of your friend's life. You may only get a fraction of a second, and then its too late.

From what I have seen from special forces, the desire for guns is always to pare them down to simpler and simpler devices which are almost failproof.

Also, you'd be surprised at how distinctive different sounding guns are. I don't have much experience with blanks, but it would surprise me if you could generate a good enough match on the acoustics to trick enemy soldiers, whose lives literally depend on their ability to tell whether you are firing real bullets or blanks. The human ear can do some staggering things.

  • $\begingroup$ The 'failproof' argument you raise is a tough one. I think the sound signature issue can be settled ( quite silent 'real' shoot <-> very similar to the fake ). I though in fact of a two-triggers weapon, which allows instant switch of tactic. $\endgroup$ Mar 26, 2016 at 22:41
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    $\begingroup$ +1 for the human ear doing staggering things. I am connecting this statement with the perception of balance system in the human ear, not matter what you intended it to mean :D :D $\endgroup$ Mar 26, 2016 at 22:47
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    $\begingroup$ Speaking of the sound, it occurs to me that a big part of the sound signature comes from the supersonic boom of the bullet passing thru air. And that if someone is firing at you, you actually hear that first. So faking that without actually shooting the bullet might be impossible. $\endgroup$ Mar 26, 2016 at 22:53
  • $\begingroup$ @VilleNiemi : Yes, i think that if you shoot randomly real or fake rounds, enemy just gets crazy about what the sound means. $\endgroup$ Mar 26, 2016 at 23:00
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    $\begingroup$ Another point being missed here is logistics, and the military principle known by the acronym SNAFU. If you have two otherwise identical magazines, one with blank rounds and one with live, it is absolutely certain that some units will get nothing but the blank magazines. $\endgroup$
    – jamesqf
    Mar 27, 2016 at 17:42

The larger problem is that the vast majority of firearms require special preparation to use blanks. For gas powered weapons, a blank firing attachment (BFA) is needed to partially block the barrel and allow enough gas pressure to build up in the barrel to cycle the action. (Edit for clarity: the gas pressure in the barrel is vented into a separate cylinder to drive a piston or the bolt carrier which cycles the action. I realized the initial statement might not be clear for people not familiar with firearms).

M-16 BFA

Even recoil powered weapons like the .50 HMG need for the recoil to be boosted by a blank fire attachment like the one below:


So in addition for the soldier changing magazines, they must also add or remove the blank firing attachment. IF they fail to put the BFA on the weapon, there will not be enough gas or recoil to cycle the action. If they don't remove the BFA when they fire a live round, then they risk having the round strike the BFA mechanism and cause a massive mechanical failure. For this reason, exercises using blank ammunition need to be carefully controlled by the Non Commissioned Officers to ensure live and blank ammunition are never mixed.

Hollywood weapons don't have visible BFA's since the barrels are often carefully modified to obstruct the flow of gas to create the same effect. Of course, the obstructed barrel would not allow for the use of a real bullet.

In the future, the effect of covering fire may be handled by "smart" ammunition and especially smart rifle grenades such as fired by the XM-25. Rather than a blizzard of rounds which might hit an enemy soldier, there will be a series of explosions over likely cover and hiding spots the enemy solders might be in


  • $\begingroup$ Indeed, blanks are used (or were, some time ago) in training exercises. With M16, in my case, and IIRC blank firing adapters were used. $\endgroup$
    – jamesqf
    Mar 27, 2016 at 4:37
  • $\begingroup$ That grenade launcher is now back in development after a grenade detonated prematurely and injured the soldier firing it (or something along those lines). The US military is quite excited about them, however. $\endgroup$
    – AndreiROM
    Mar 28, 2016 at 15:18

Even if you can make fake ammo as cheap as real, while still reliable in weapon and making realistic sounds and you can change fake and real on whim (4 x unrealistic but play with it)

THEN it can help somehow in only few and very Hollywood scenarios, where YOU with lot of units around try to catch ME (with max 2-3 friends in small compact group), on place with just one opening and WE will have nearly no guns and/or ammo. And YOU fire your fake covering fire with occasional real bullet in it, so I would not dare go out. You need suppress my fire for long enought to your forces can reach and neutralize me.

But in any little more realistic scenario you will have big problem: ME and my (possible) friends.

  • You are afraid of us (otherwise you will just came clear and plain) and we know it (same reason)
  • we can fight somehow and we will.
  • if there is only one opening between us, maybe I will be scared to show myself there, while I hear fire from outside, but even so, I will soon realize, that there is nearly no bullet hitting it, so your cover fire is (who know why) concentrated somewhere else. Time for me to try the oldest trick - helmet on a stick
  • wow, lucky - helmet really not hit, next time I will try with my weapon and shoot at anything I could see on fast glance - either some soldier running toward me, or you, as your weapon makes some visible flashing effects. Then I fast hide again.

Now you have to spot me on the flash, your gun blasting uselessly and change the ammo to hit me. Would you just wait silently with finger at trigger, you would see and hear more, I will not see your position such easily and I may be less carefull, no bonus for wasting fake ammo, but now you have really hot barrel (as fake make at least as much of heat), with your position nice marked, your gun less acurate (long fire heats the barrel and sustained fire needs to change the barrel sooner or later (in term of minutes)) so you are at disadvatage.

The more, if I am not alone, or I have more windows/holes for use, so I can suppose, that if no sream of bullets goes around me, you are just covering other spot, where I could be/I was/my friend is and I will use the windows of no bullets to send as much bullets your way, as I can.

And I use all real bullets.

If there are like 4 or more automatic weapons on your side and 4 or more any weapons on our side on different spots, I have none real eveidence, WHERE are you shooting with which gun and so I suppose, that all the fire and bullets goes somewhere else and I can shoot safely until some bullets came hit my area near me, before I need to take cover.

So basically if you face few opponents, any of your fake rounds are basically wasted and only the real one counts.

The fakes cannot even hit by luck, or make some debris scracth me, or cover my vision.

(but you have to pay for the fake anyway and carry them and they would heat your weapon so on long fire even consisting of empty bullets, you are forced to change barrel or wait, it it cold a little now and then. And all those fakes makes harder to you spot me (your enemy) and wears your stamina with recoils (hard enought to cycle your weapon reliably).

In any larger encounter (4+ vs 4+) your fakes gave advatage to OUR side and disadvatage to YOUR side.

If you want mixed belts, than tracer helps you see, what point you are exactly hitting, and some incidentary could make fire on my side, some explosive can hit somebody just around corner, or at least scratch his face with fragments, occasional AP would take down some hardened point on our side, that could make some sense sometimes, but empty are just empty and do bad only to your side.

well one use of empty is possible - to panic unarmed civilians without big casaulties, but even so, it is bette to just shoot over their heads to anything durable and give it bettere realistic feel, when small debriss are flying the air and brick powder is on theirs heads ... and if they went to desperately attack you, then you have something to deefend yourself anyway.


No possible blank could mimic the crack of the bullet as the sound comes from the passing bullet, not the gun. The gun isn't anywhere near where it needs to be to make it.


The obvious solution would be loading mags mostly with blanks. Something like one live round every 4 blanks for instance. It's common when shooting LMGs to have tracer rounds every few rounds, so the concept isn't so far off.

The real question is why would you go to war with blanks? Shooting live rounds when suppressing/covering has the added bonus that you might kill something by happenstance. If your life depends on your ability to transform a human being into Swiss cheese, you wouldn't take a gun full of blanks to combat.

  • $\begingroup$ I was thinking here of the ability for a warrior to hold way more fear force than lethal force. Inn a cover fier, the fear leads the way to the death. $\endgroup$ Mar 26, 2016 at 23:03
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    $\begingroup$ Lethal force is scary enough by itself, I imagine. Then again, I've never been shot at. On the other hand, what about going to combat with a gun you know for a fact has only a 20% chance to fire a live bullet? I don't think it would be very comforting for the guys carrying the rifles. $\endgroup$ Mar 26, 2016 at 23:07
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    $\begingroup$ The difference between a blank and tracer is that the blank will probably cause the machine gun to jam. Furthermore, there is simply no tactical advantage to firing blanks in an armed engagement - not under any circumstances. $\endgroup$
    – AndreiROM
    Mar 28, 2016 at 14:29
  • $\begingroup$ I'm assuming the gun can fire whatever you feed it without breaking in half. $\endgroup$ Mar 28, 2016 at 14:45
  • $\begingroup$ Basically, you assume wrong. With blanks the most likely scenario is that the gun wouldn't break in half, it just wouldn't fire. Guns can be very ammo picky. If you load the wrong caliber ammo the gun can blow in your hands. If the powder mixture is off (self loaded cartridges, for example) your gun will either not cycle (not enough pressure, which would be an issue with blanks), or blow up (too much powder means too much pressure). Some guns won't even work with the correct caliber ammo unless it's high velocity, or vice-versa. Ammo quality is also a factor. See some of the above answers. $\endgroup$
    – AndreiROM
    Mar 28, 2016 at 15:16

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