Question about ambient bullet sounds .actual or random.

[BeerHunter 0]

I'm wondering if the bullet snaps you hear are actually relate to bullets passing close to you or are they simply ambient sounds inserted for atmosphere?

And , when you use a sound mod , is it the same? (actual bullet tracking or just random sounds generated for atmosphere).

[Yoshama 0]

BI doesn't have built in ambient sound except for animals and stuff. any combat sound you hear is actually happening. i've set up missions with combat on the other side of a hill and it sounds amazing! some times tho a mission creator doesn't want to lag the system with too many objects so they will add in ambient combat sounds, but you need to insert a sound file for that. and then it usually doesn't sound right

[Alex72 1]

Its the same with addons yes. They just replace the sounds to their own. Sometimes they even come up with new things like MarkXIII that added passing sounds from AT-4's etc.

But the sonic cracks are a result of a bullet passing close to you. And rocket/missile swooshes. :)

Alex

[-RIP- Luhgnut 10]

oh, for sure, they are shooting at you and not ambient. setup something in the editor with a one on one instance. Let the other guy shoot at you while you hide behind something. If he doesn't hit you on first shot, you'll hear the snap closer to your head. It's pretty freaky.

[Sniperdoc 0]

You know... I've been on many a range and I've never heard that snap a single time...? I'm talking M-16A2, M40A2 and the occasional M9... and I've been on the receiving end with bullets going overhead. Like 5 - 6 feet overhead. For those of you who have been in the service and been on some of the Camp Pendleton Rifle Ranges know what I'm talking about... especially 8541's...

[maturin 12]

I don't get quite how it works either. If the bullet causes a crack, why do you get the whine sound sometimes?

Some Danish guy posted a video of his squad getting ambushed from a hundred meters away and the snaps were deafening.

[dogz 10]

Sniperdoc my experience is similar to yours and I have had rnds strike hard rock very close to me.

I have never heard a definate snap, I can only assume that unless you are far enough away from the main noise of the shot it gets drowned out.

I have heard something like a snap over grain crops on very open ground.

Speed of sound is about 1100fps so it makes sense that at the higher velocities in theory the bullet breaks the sound barrier.

For most of the rounds that would not be the case at long range (after 500 -700 meters)

I have heard different whine sounds most from ricochet but if my theory is correct it would be as the bullet slows below the sound barrier it is still displacing the air so should make some sound.

[ARM505 0]

I've definitely heard it, every time I've been in the trenches under the targets - in fact it was just loud enough to make my ears ring. This was with 7.62X51 at 100-300 meters. It's like a loud snap. ARMA's rendition somehow doesn't seem to convey enough authority somehow, although the sound is close. Maybe it's because IRL it's an actual bullet passing close to your head! Sort or like the crack of a whip almost. But it was definitely that little sonic shock wave from the bullet. The muzzle report sounds totally different and is clearly a separate sound.

[dogz 10]

yeah well that makes sense as you are in the ideal place and distance. I agree the arma sound seems a bit high pitched.

[-RIP- Luhgnut 10]

In a former life, I was a semi-pro handgun speed shooting competitor as well as PPC semi-pro. Meaning I wasn't good enough to actually make a living at it. :) I've realoaded my own rounds and worked out loads for rifles/handguns.

Anyway, here's what happens, there are actually two sonic booms from a hyper-sonic round. One when the bullet exceeds the speed of sound and one when it drops out of speed of sound. If you are standing in between those two sonic booms, you won't hear the snap. If you are close to where it enters or exits the speed of sound, you will hear it.

You probably won't hear the first crack because that happens either at the muzzle of the rifle or inside the barrel but the sound is caught inside the expanding gas pushing the bullet out. Once the bullet leaves the barrel, the sound exits with it, but there's so much going on, you don't hear it. Now if you're down range like at the gun range and bullets are going over your head, the bullet may be still be traveling faster than speed of sound. It won't drop out until it starts to really slow down, but that is further downrange and the bullet starts to become really unstable and starts to tumble. It's possible a 7.62 Nato round will stay above the speed of sound for nearly a mile, but the bullet starts to tumble around 200meters and the bullet is much less accurate and probably I would guess drop out of SOS between 200m when it starts to tumble and when it hits something. But probably around 200-250 Meters. Furthermore, once a bullet drops out of SOS, IT REALLY GET'S SQUIRRELY, cause it can't stablize and you'll have bullet's going every which way.

(side note) taking shots at > 200M with an AK-74 in Arma2 is unrealistic. The bullet will travel that far but it's so unstable that it will fly all over.

That's the WHIZZ sound you hear. Either the bullet becoming unstable, or you're hearing imperfections on the actual bullet which it has picked up either hitting twigs on branches, or the rifling on the bullet from leaving the barrel, or more likely hitting dirt and bouncing, or maybe you're just far enough away that the bullet is just normally slowing down.

Now in Arma2 you have bullet's coming from all directions, the chances of a bullet falling out of speed of sound either by hitting dense pockets of air (which slows it down) hitting tree branches, or even high grass may cause it to drop out of the speed of sound. And you hear it in the game.

I've seen wildcat rounds shot in the early morning through dense ground fog just shred because the bullet is going so fast, and the dense fog (water vapor) will literally shred the bullet to pieces. You can easily see the bullet come apart and fly all different directions through the fog. Cause the fog just swirls where the pieces go. Pretty cool but useless.

How silencers work. First you need a subsonic round, meaning you need a bullet that doesn't break the sound barrier. The silencer only silences the boom of the expanding gas leaving a barrel. So in the movies, when you see a sniper rifle with a silencer, no way. The silencer would probably have to be 20-30 feet long or longer. (haven't worked out that calculation cause it's meaningless) but the silencer would have to be super long to capture all of the supersonic gasses and the sonic boom (crack) of the bullet, as well as capture the bullet falling out of supersonic....if you think of it. So to use a silencer you need special loads that are slow. The most perfect handgun round to shoot slow is the .45ACP because they push a bullet along at around 750-800 FPS. So silencers in movies on .45ACP is very possible. 9mm Silencers 115Grain 9mm Bullet does a screaming 1600 - 1800 FPS. It's a fast moving BB compared to the .45ACP. So they take the 9mm, put a heavier bullet in it say 120Grain, and then slow it way way down below subsonic. Then cram it in the MP5 and now you have a very fast cycling 9mm subsonic round with a silencer. The .45ACP doesn't cycle as fast as well as you can't get as many rounds in a gun cause the .45ACP round is nearly twice the diameter of a 9mm, so they go with the 9mm. The 9mm bullet is pretty useless over 100m at best. So it's great for short range tactical entry stuff. The slower bullet won't penetrate walls as much to hit other officers entering or hostages. Deadly at close combat range. The .45 is like being punched in the chest, and the bullet has so much kenetic energy that it will blow right through walls. The 9mm doesn't have the kenetic so it basically shatters when hitting anything except soft tissue at subsonic speeds. Personally I feel .45 is a better round for defense and is my summer time carry gun because when the kenetic energy hits, it can literally take your spleen and puts it over your shoulder. The 9mm bleeds you to death. In winter time, it's a .44Mag.

Thus endith todays lesson

Edited September 3, 2009 by [RIP] Luhgnut

[dogz 10]

Luhgnut

if you visit Remingtons website they have ballistic tables that show that the 7.62 rnd does not stay supersonic for anything like a mile... depending on the bullet weight and muzzle velocity etc on average they fall below the speed of sound between 500m and 800m.(1/2 a mile)

I have also never seen any good quality rifle bullet tumble at useable ranges unless it was to come into contact with something.

I have done accurate shooting out to 1000m and never seen an oblong hole in a paper target, only round ones.

If bullets tumbled in normal flight.... ie you say 200m... you would never hit anything at longer ranges and they would slow down exponentially as well as leaving a hole in the target that is not round in shape.

I have seen a million bullet holes in targets and not one was anything but perfectly round..

[Sniperdoc 0]

I would have to agree with Dogz... I've never seen an oblong bullet shape... even my Snipers shooting at moving targets 1,200m out. No oblong bullet holes. Just round ones. Plus if you take into account Field Med school where they taught me that the round only tumbles when it enters the body... ya... no tumbling in flight. :)

@Dogz:

Could very well be that our range that we consistently used was over 600m (it has been 11 years). By the time they built the moving target range with the 1200m targets, we had been deployed to Okinawa shortly after.

I also agree with you on the fact that this "snap" they have in Arma is very weak. It's something that really is kind of a turn-off and makes it sound very antiquated, i.e. OFP style. It is also one of the few reasons one of my buddies won't purchase Arma 2. If they'd fix that snap and make it sound more authoritative, then I might even buy it (i.e. believe more that it is a bullet passing by).

Here's a VERY good response about this http://forums.bistudio.com/showpost.php?p=1344952&postcount=36. It also, to me, sounds nothing like what they've presented in the game.

Edited September 3, 2009 by Sniperdoc

[dogz 10]

@Sniperdoc

yep good vid demo of supersonic cracks I obviously spend too much time at the loud end of the range... :)

A2 needs to beef them up and stretch em out to make them believable.

BTW 1200m at moving targets thats tough I would need MG...lol

[-RIP- Luhgnut 10]

Luhgnut

if you visit Remingtons website they have ballistic tables that show that the 7.62 rnd does not stay supersonic for anything like a mile... depending on the bullet weight and muzzle velocity etc on average they fall below the speed of sound between 500m and 800m.(1/2 a mile)

I have also never seen any good quality rifle bullet tumble at useable ranges unless it was to come into contact with something.

I have done accurate shooting out to 1000m and never seen an oblong hole in a paper target, only round ones.

If bullets tumbled in normal flight.... ie you say 200m... you would never hit anything at longer ranges and they would slow down exponentially as well as leaving a hole in the target that is not round in shape.

I have seen a million bullet holes in targets and not one was anything but perfectly round..

ahh... I mean the standard issue Nato round. The crap the chinese would put in their guns. A standard 7.62 Nato FMJ canned round will "wobble" at around 180meters. I was guessing at the supersonic ranges if the bullet would stay straight and cool. But they don't. and what I should of said instead of tumbling, they sort of wobble like a boat trying to go upstream So you'll get round holes. So they don't actually "tumble" more more of a wobble.

I was shooting 9mm Bowling Pins and my gun was shooting nuts. At as little as 25 feet, the rounds weren't hitting, then one pin sorta just fell over funny and spun around, I picked up the pin, and sure enough was a silouette of a 9mm round. The problem was that my barrel was slugged at (if I remember correctly) .258 diameter. The rounds were micro'd at .256 so the bullet was actually slopping down the barrel, and when leaving would kick sideways out. I never heard of such a thing. But my gunsmith told me that 9mm guns and ammo can range from .255 diameter to .258!!! Sure enough, I micro'd several 9mm rounds and depending on brand, there was a wide variance. My point being, any small out of calibration can have major changes in result downrange. Oh also, if you take a heavier bullet and shoot it fast enough, it will stay above the supersonic speeds longer, it's when they start to wobble, and slow down is when they become accurate. So say, you're shooting at your 1000m targets. With a decent round, the bullet will stay above supersonic speeds maybe 1500Meters. So you aren't slowing down, and hence more accurate. It's when you're target is close to the point of instability is when it starts cracking and being unstable and inaccurate.

Take the Barrett for example, that sucker is .50 cal, moving hyper fast. I think it's point blank range is nearly 1000yrds, meaning the bullet hasn't even started to rise in it's arc. It's some insane number. So you don't have to compensate for bullet drop till way way out. The bullet is moving so fast, and so heavy, that it's accuracy is like off the charts for a very long distance. I would guess the bullet doesn't drop out of SOS or become unstable for, man.... a mile? Gonna have to look that up.

I too have shot AR15 rounds at around 800Meter fairly accurately, but had to float the barrel, and have some nice tight sharpshooting rounds. The .223 round is more stable from an AR15 than the 7.62 Nato out of say an SKS. I found the 223 a much better accurate round than the 7.62. The .762 round is heavier and out of a better gun is quite nasty. But the AK47/74 standard is sorta crappy.

Also the 7.62 canned rounds have really whacky loads. You take 12 rounds apart, measure the weight of the bullet and the powder and they are all over the chart. As well as the powder burns your eyes, tastes and smells nasty.

I don't have the load data in front of me, and it had to be around fifteen years, ago, so I don't have exact FPS or TKO data.

Edited September 3, 2009 by [RIP] Luhgnut

[dogz 10]

@Luhgnut

I dont want to sound like an ahole as I do hear where your coming from re the wobble but...

below is some actual physics to show the trajectory of a .50 cal BMG round.

I nearly purchased one of these in a non military version but decided against it due the very fact that it has a shocking arc in its trajectory.

It is actually already 24 inches above the LOS at 100m when zeroed at 1000m

Of course this does not effect the accuracy or power just the aiming.

If you read the table I have pasted below you will see that when zeroed at 1000m it has an arc in the bullet path above the LOS of 76 inches thats about 2m.

So if you zero to hit where you aim at 1000m then you will have to hold under the 500m target by 2m, of course many sighting sytems can be adjusted on the fly to shift the zero shot to shot.

Input Variables Firearm type Rifle Sight Height 1.5

Bullet Weight (grains) 700 Ballistic Coefficient 1

Muzzle Velocity (fps) 2800 Temperature 59

Barometric Pressure (hg) 29.53 Relative Humidity 78%

Zero Range (yards) 1000 Wind Speed (mph) 0

Ballistics Table in Yards 700 gr., 1 B.C. www.hornady.com

Range (yards) Muzzle 50 100 200 300 400 500

Velocity (fps) 2800 2754 2708 2618 2530 2444 2359

Energy (ft.-lb.) 12185 11787 11400 10656 9951 9283 8651

Trajectory (1000 yd. zero) -1.5 12.1 24.6 45.9 62.2 73.1 78.2

Come Up in MOA -1.5 -23.1 -23.5 -21.9 -19.8 -17.5 -14.9

The following table is provided as a "cheat sheet" that you can tape to your gun.

Ballistics Table in Yards 700 gr., 1 B.C. www.hornady.com

Range (yards) Muzzle 50 100 200 300 400 500

Trajectory (1000 yd. zero) -1.5 12.1 24.6 45.9 62.2 73.1 78.2

Come Up in MOA -1.5 -23.1 -23.5 -21.9 -19.8 -17.5 -14.9

--------------------------------------------------------------------------------

Ballistics Calculator v1.0

Hornady Mfg, Inc., by ARIS, Inc.

The 50 cal does also have a sabot round that fires a 400 gr projectile at 4000 fps and has a arc of more than half of the std heavy bullets.(42 inches)

Edited September 3, 2009 by dogz

[-RIP- Luhgnut 10]

Cool. I stand corrected. Man, a 400 Grain (fairly light) at 4000fps with a a 42 inch drop at 1000? that's not much at all.

I looked at getting one of these monsters too. But couldn't find anything to reload the rounds. They're prolly out now though. Friend wanted one to shoot woodchucks with. Go figure.....

[dogz 10]

If I was to buy my dream LR rifle now it would be the Cheytac 408

40 cal 400gr @ 3000 fps

More power than the 338 Lapua Magnum flatter than the 50 cal ( sabot rnds are not legal in AU- no rifling marks on projectile )

go check it out or Youtube it

http://www.cheytac.com/Products/CheyTac408.asp

Edited September 3, 2009 by dogz

[Sniperdoc 0]

Hehehe I have a tricked out Remington 700 LTR. Forget what the scope on it is. It's a Burris of some kind. Really nice though... with a laser cross hair for twilight/night shots. I also have a Harris Bipod. http://www.youtube.com/watch?v=hcIC409eXEs Man... haven't shot in forever. Need to go out again. :)

Just curious... you guys are talking about a parabola when the bullet exits the barrel...??? I've never heard of that... Nothing goes up when it exits the barrel unless the barrel is pointing upward. Everything drops...? If you adjust the bore to the scope for longer distances, yes, in essence you're shooting up by default to hit your target where your cross hair was at. But, there's no bullet parabola...? I remember that much from my indoc... :)

Edited September 3, 2009 by Sniperdoc

[dogz 10]

Sniper maybe I was not clear but if you read my post again you will note my reference to LOS and trajectory.

I will explain but I am sure you know this...

LOS stands for Line Of Sight which is the direct line to the target through the scope and trajectory is the bullet path.

Yes gravity forces the bullet to start falling as soon as it leaves the muzzle so we must tilt the barrel up to compensate.

This causes the LOS and the bullet path to converge and cross over so the bullet in fact travels in an arc or trajectory back down to point of impact just like throwing a long ball from the outfield to a catcher... you look straight at the guy but must throw upwards to make the ball hit the glove.

If you go to any ballistic table on the web you will see diagrams of this.

Go here and scroll down the page http://www.hornady.com/ballistics/external.php

A quote from the text of one of the most highly regarded bullet manufactures in the world...Hornady

A trajectory is a description of the flight path of a projectile relative to some known and fixed points. Trajectories for BBs, field artillery projectiles, naval gun shells, mortar rounds, and small arms bullets are all parabolic in shape.

Edited September 3, 2009 by dogz

[Sniperdoc 0]

Ok ok... now I understand what you meant :) Just sounded odd. ;)

Your bore sight crosses the scope sight... gotcha :)

I mean I've heard of bullet lift before, depending on the angle of the wind from either side and the spin of the bullet producing an extremely minor rise in the bullet path... but that's so rare.

All's well...

[-RIP- Luhgnut 10]

Ok ok... now I understand what you meant :) Just sounded odd. ;)

Your bore sight crosses the scope sight... gotcha :)

I mean I've heard of bullet lift before, depending on the angle of the wind from either side and the spin of the bullet producing an extremely minor rise in the bullet path... but that's so rare.

All's well...

You can actually get a bullet to sorta "air-bounce". It's like a frisbee when it get's to the ground and the wind coming down makes a cushion and it sorta floats on it. It's rare and only for big calibers. It's like an airplane when it flairs. The distance to the ground is the same distance from wingtip to wingtip. But a bullet has to be pretty close to get an air-bounce and it's so slight it's hardly noticeable at all. Only on charts and in theory.

---------- Post added at 06:27 PM ---------- Previous post was at 05:38 PM ----------

I want to curve bullet's like Angelina Jolie.... that was badass.

[JackandBlood 10]

They are actual indicators of the bullet passing close to you. Remember this game doesnt use hitscan point and click gun mechanics. Every bullet is modeled as an object, so when one passes close you will indeed hear that crack or hiss. I love talking about this feature cuz I think its so cool and it exists only in BIS games.

[sniper pilot 36]

Superb post Luhgnut! Very informative, and interesting.