Use of subsonic ammunition in ArmA2

[Inkompetent 0]

I've time and again got irritated on the fact that there's no 'in-between' for using a suppressor or not in ArmA2. It doesn't matter if I use a suppressed weapon or not as long as I have the right ammunition, since all detection values for muzzle flash and sound bang are defined in the ammunition.

However as I understand it at least M4A1s, and especially sniper rifles (not that we have suppressed sniper rifles other than the KSVK in vanilla ArmA2, and that gun works as it should since it's a built in one, but just making clear) are usually NOT used with subsonic ammunition unless necessary since it has quite terrible performance, and absolute silence isn't as necessary as just not letting the target know where you fire from, or not realize shots are being fired until you have shot several times.

In fact suppressors increase accuracy and they increase muzzle velocity, however with the two main issues being a shifted zero due to altered center of mass for the weapon, as well as making it more front-/barrel-heavy, and increased malfuntion rate due to higher gas pressure.

At the moment however I'm forced to choose between 900m/s loud and highly visible shots, or 320m/s silent and invisible shots.

It is fairly reasonable from a game balance perspective I guess, seeing the Russians use subsonic ammunition for their AKS-74UBN and its PBS-4 suppressor.

Mods are here to make differences though, and I'm curious first and foremost: During what circumstances would subsonic ammunition be used by a soldier with a weapon capable of firing full-power ammunition through its suppressor? When storming buildings to decrease the disorienting noise? For 'absolutely-can't-get-noticed'-missions? For jungle warfare where fighting ranges are so short it's irrelevant if you use subsonic or not?

Just trying to get a better understanding of things here, since information on the topic is hard to find, for basis to decide whether I should look more into proper properties of suppressed weapons using full-power ammunition.

Edited May 7, 2010 by Inkompetent
Added a little about sniper rifles

[maturin 12]

The suppressors are indeed annoying. Especially since most of the sound mods available mimic that of suppressed weapons firing normal supersonic ammo while paintballs that barely wound the AI are coming out of your gun.

[Imperator[TFD] 444]

(not that we have suppressed sniper rifles other than the KSVK in vanilla ArmA2, and that gun works as it should since it's a built in one, but just making clear)

You're thinking of the VSS Vintorez. The KSVK is their anti-material weapon, similar to the M107 Barrett.

[sneakey pete 10]

I thought that the low power subsonic ammunition wouldnt work in the unspressed weapons, lets say a m4, due to the lower grass pressure not being enough to overcome the spring. Put the silencer on and it restricts it enough to work properly? (and of course, full power ammunition overpressurises it, leading to failure?)

As for reasons for wanting to use subsonic ammunition in your M4 or other weapon, but without a silencer... i really wouldn't know. Sure, its not going to be as loud... but i wouldn't have though it would reduce to being a third as loud. Still quite a lot of noise.

Of course, i can't say for sure. Don't have silencers, m4's and my own different ammunition loads in this country.

Edited May 7, 2010 by sneakey pete

[Inkompetent 0]

You're thinking of the VSS Vintorez. The KSVK is their anti-material weapon, similar to the M107 Barrett.

Actually I do mean the KSVK. It has a built-in suppressor and recoil compensator, and it uses full-power ammunition. Forgot about the VSS, but contrary to the KSVK it doesn't use full-power ammunition, but the subsonic 9x39mm SP-5 cartridge.

I thought that the low power subsonic ammunition wouldnt work in the unspressed weapons, lets say a m4, due to the lower grass pressure not being enough to overcome the spring. Put the silencer on and it restricts it enough to work properly? (and of course, full power ammunition overpressurises it, leading to failure?)

As for reasons for wanting to use subsonic ammunition in your M4 or other weapon, but without a silencer... i really wouldn't know. Sure, its not going to be as loud... but i wouldn't have though it would reduce to being a third as loud. Still quite a lot of noise.

Of course, i can't say for sure. Don't have silencers, m4's and my own different ammunition loads in this country.

That's a good point actually. For example the FN SCAR and Bushmaster ACR has a gas regulator valve that the user can adjust depending on if they use subsonic ammunition or not so that they don't have to change internal components because of ammunition-change.

Don't think that's possible on the M4A1 though (someone please correct me if I'm wrong. I just can't find any info on gas regulator valves on M4s).

Also, I'm not talking about use of subsonic ammunition without a silencer. It'd be quite pointless since the muzzle blast would be so loud you could just as well use full-power ammunition with a suppressor and pack 4x the punch. Just sort'a wondering about the SOP for subsonic ammunition, since other than in very special cases it seems like a waste of weapon range and stopping power.

Edited May 7, 2010 by Inkompetent

[JSj 12]

Actually I do mean the KSVK. It has a built-in suppressor and recoil compensator, and it uses full-power ammunition.

I think you need to decide what you are talking about here. It seemed like the thread was about silenced weapons and subsonic ammo, that is, weapons that are made to be quiet.

Yes, the KSVK has a muzzle brake/compensator (as do all heavy caliber weapons, like the Barrett for example) to reduce the massive recoil and noise a little bit, but I don't see what that has to do with this topic. It is by no means a supressed/silenced weapon, unlike the Vintorez.

[maturin 12]

I thought muzzle brakes made the weapon louder.

[JSj 12]

I think they might make them louder in some directions than what they would be otherwise, as it deflects the gasses in other directions than forward. Anyway, the muzzle compensator thing on the KSVK dampens the sound a bit, but it does by no means silence it.

[Inkompetent 0]

As I say in the first post, as I understand it the usual way of using suppressed rifles is with full-power ammunition unless it is under very special circumstances. The only example of a suppressed weapon firing a full-power round in vanilla ArmA2 however is the KSVK (although the suppressor there is to bring the noise down to a non-retarded level rather than to make the shooter really hard to spot), even though it's been in practice since WW1 to use suppressors on sniper rifles to make the shooter 'invisible'. So in lack of better in-game examples it got the spot.

Still, do anyone know (or at least can point me to) SOPs for use of suppressors and full-power vs subsonic rounds (in particular for assault rifles)? For example how common is it to use suppressors and full-power ammunition rather than skipping the suppressor completely? Or is the current modelling in ArmA2 adequate enough for the most common uses?

Edited May 8, 2010 by Inkompetent

[andersson 285]

The reason to use a suppressor (note the word suppressor, not silencer) on assault rifles is to protect your own hearing. The sound will still be loud but a drop from 110+dB to 90-100 dB is a big difference for your hearing. Another benefit is that the sound is more difficult to pinpoint from distance. You can hear it but its more difficult to hear the exact location of the shooter. You will still use normal ammunition.

A suppressed weapon is not silent.

My friend and I did some tests with different suppressors on a M16. We recorded the dB from different positions (next to shooters ear, next to barrel and different positions infront and to the side). We also took data from a clean barrel and using the standard muzzle brake.

I can put the data here tonight if anyone is interested?

I think one of the reasons for special magazines in arma2 for suppressed ammunition is that the values for AI hearing the shots are defined in the magazine. If you load the "normal" magazine into a suppressed weapon the AI hear you just as good as if you were shooting an un-suppressed weapon. Its a limitation, its been suggested to define that in the weapon instead to get around this issue.

If you want to go silent, not suppressed, then you need a silencer and sub-sonic ammunition.

About the gas valve. I dont know about other weapons but the finnish RK95 has a gas valve. That is used to give extra punch when you shoot a grenade from the barrel (you know the type you slid into the barrel and then you shoot a normal round up its @ss and away it goes). I think it also can be used if the weapon is too dry and shitty and you really need it to work, heard something about it. Not sure if that is official procedure though.. ;)

[Deadfast 43]

My friend and I did some tests with different suppressors on a M16. We recorded the dB from different positions (next to shooters ear, next to barrel and different positions infront and to the side). We also took data from a clean barrel and using the standard muzzle brake.

I can put the data here tonight if anyone is interested?

Sure, go for it ;)

I'm sure I'm not the only who'd like to see the results.

[galzohar 31]

The main reason I doubt hardly anyone really uses subsonic 5.56 ammunition is the simple fact that a subsonic 9mm would carry more energy, so might as well use that (aka MP5SD, or a Bizon) if you want optimal suppression.

The engine currently does not allow for a pretty solution for having normal ammunition in a suppressed weapons, but ACE did find a reasonable workaround which you hardly even notice (that is, their workaround works almost as well as if BIS would've fixed the engine limitation instead). Of course it seems a lot of people don't even understand how the ACE system works and that they can actually use normal ammo in suppressed weapons and get some nice effect against both humans and AI.

[sparks50 0]

Is it even possible to define caracteristics by both weapon type and ammo?

Edited May 9, 2010 by sparks50

[Inkompetent 0]

I know a suppressor is only supposed to reduce about 30dB from an assault rifle, give or take some.

The point is that even if using full-power ammunition and a suppressor (i.e. an ammo configed to have higher initSpeed, and lower detection values both for hearing and sight than for an unsuppressed rifle) there should be certain benefits. The argument could be that "well, then everyone will use suppressors". And yeah, sure. they will. If allowed to. That's the mission-maker's responsibility to sort out.

If a rifle can't even be altered without changing internal parts though, then the useability of such ammo being added to the game for other than the ACE2 TAC-50 (bolt action and suppressed, thus no need to change parts for the change of ammo) can be questioned.

[galzohar 31]

IRL, cost is not the only thing stopping armies from equipping all their soldiers with suppressors. There's also the weapon length and weight issue which is not simulated in the game in any way, as well as the suppressor wearing out after a certain amount of shots are fired (not sure how many, though, and it probably depends on the weapon and ammo too).

[andersson 285]

Here are the figures from the dB test of some suppressors:

                   ear      2m 90 deg     10m 45 deg      20m 45 deg
#1                  127.9    122.7           
prototype           125.2    124.3         130.8           128.1
#2                  135.7    138.1         138.1           131.4
#3                  140      139.1
M16 flash hider     140.6    141           139.1           134.3

ear = next to the shooters left ear

2m 90 deg = 2 m away 90 degree out to the left of the muzzle

10m 45 deg = 10 m 45 degree out to to the front-left of the muzzle

20m 45 deg = 20 m 45 degree out to to the front-left of the muzzle

This is all dB peak. There were other values that we could get out from the tests but I didnt understand that data (sound curve and total dB or something like that).

Remember that dB is logarithmic so at these levels the change is bigger than it looks by the numbers. But even if the sound is alot lower its still high dB with a suppressor and standard ammunition.

This test was all done outside without any walls or hard surfaces around. The terrain had low vegetation and sandy ground. We were standing on lower ground but no extrem topography.

"prototype" is what my friend made and wanted to test and he was mostly curious to test it against a certain suppressor (#2), thats why we have the 2 extra tests for them.

I didnt use the names of the suppressors here as that doesnt matter and I dont want to put that info here.

Edited May 9, 2010 by andersson

[Inkompetent 0]

IRL, cost is not the only thing stopping armies from equipping all their soldiers with suppressors. There's also the weapon length and weight issue which is not simulated in the game in any way, as well as the suppressor wearing out after a certain amount of shots are fired (not sure how many, though, and it probably depends on the weapon and ammo too).

Modern Reflex suppressors take about 30.000+ rounds to get worn out since they consist of 100% solid steel.

But indeed the weapon length and weight is an issue (the length is already in usual ArmA2, and length+weight in ACE), as well as the price, plus for example compatability with weapon attachments. The SOPMOD suppressor is for example counted as a fairly bad suppressor, one of the problems being that it makes the weapn very front-heavy, but one of the reasons for that is for it not being in the way of the front attachment point for the M203 launcher (i.e. the suppressor doesn't 'sleeve back' all the way to the sight around the barrel, but just a few inches).

Nice test data, btw. Out of curiosity, what kind of suppressor was that, and how many baffles does it have?