Silenced sniping weapons and thier practicality

[Evil Monkey]

While reading up on some rifles designed around stealth, like the silenced subsonic 9x39mm rifles from Russia and 300 & 338 Whisper rounds in AR15 platforms, I've realized a few things.

These rifles are developed to:
1) have ballistics better than pistol rounds, for long range shooting (up to 300-400meters)

2) eliminate the super sonic crack as the bullet travels to the target.


I have issues with number two. Isn't the super sonic crack non-directional? So if you were being shot and couldn't hear the gun shot but could hear the crack, you still wouldn't know where the bullet is coming from. So you wouldn't know who is shooting you and how far they are. Either with or without the crack, you could tell which general direction the bullet came from by the direction it impacted (in the environment or in your buddy....or yourself).

Then if the crack of the bullet is non directional and wouldn't put the enemy in a position to know where the shot came from as equally as if the bullet didn't have the supersonic crack , why not just use a very effective suppressor for existing assault/battle rifles?

 

[Gun Wielding Maniac]

The supersonic crack of the bullet would give away the shooter at the point of firing. An airgun like hiss doesn't carry as far as a high pitched snap. Shooter A is firing from 50 yards away, inside a house. Shooter B is shooting from a house the same distance away in the opposite direction from the central point. A has subsonic ammo, B has supersonic ammo. Anyone listening for FIRING nearby would be much more likely to pick up the crack from B then from A. In fact, it is entirely possible that shooter B could shoot, miss, and still get another shot because his target would not realize he was being shot at. A loud POP is an instantaneous indicator he is being fired at.

 

[Vern Humphrey]

The supersonic crack would not be silenced. US troops are trained to locate an enemy shooter by the "crack-thump" method. The crack, of course, is the sonic wave generated by the bullet in flight and appears to come from the closest point of approach of the bullet. If the bullet goes over your head, the crack will seem to come from above.

Since the bullet is supersonic (or there would be no crack), if your'e under fire you hear the crack before the thump. Troops are trained to be alerted by the crack, and listen for the thump (which is the sound of escaping gas from the muzzle.)

Sound suppressors were used in Viet Nam, and did seem to confuse the enemy. But they require so much maintenance and have an adverse effect accuracy, so they were dropped.

For specialized purposes, with sub-sonic bullets, they have utility, but so far no one has resurrected them for general use.

 

[st_albert]

To me, it seems like using sub-sonic ammo would limit you to relatively short range. Of physical necessity, a subsonic bullet has a rainbow-shaped trajectory, and even if you have a scope with a humongous range of adjustment, you would have to know the exact distance to the target in order to make corrections, because the bullet would be falling so fast by the time it reaches, say, 800 yds.

For example, a quick calculation using Pointblank, with a .308, 240 gr bullet with a ballistic coefficient of .711 and a muzzle velocity of 1000 ft/sec shows an 18" difference in point of impact between 800 yds and 810 yards. If the muzzle velocity were 3000 ft/sec, the drop would only be about 2.5 inches, and time of flight would be under 1 second vs. almost 3 sec for the sub-sonic example, thus making windage corrections much easier.

This was the main thing that bothered me about Stephen Hunter's book "The Master Sniper." Long-range accurate shooting and sub-sonic projectiles don't mix.

Albert

 

[Bartholomew Roberts]

The supersonic crack radiates from the bullet outward. So as Vern Humphrey mentioned, if it passes overhead you'll hear the crack above you as it passes.

However, the crack also reflects off of other stuff nearby as well. For example, if you fire a suppressed AR on a range with a U-shaped berm, you'll hear the round travel downrange as the crack reflects back off the side berms. In that type of situation, it isn't too hard to figure a general direction to the shooter.

I can say that modern rifle suppressors are very low maintenance and have no adverse effect on accuracy. In some cases they may even improve accuracy as well as reducing flash and recoil.

Practically speaking, Marcus Luttrell in his Lone Survivor book mentions engaging two Pashtuns at about 100yds across a ravine with his suppressed SPR. The first one toppled into the ravine. The second one heard the shot but couldn't tell where it came from and stood in the same place as the first one.

 

[wideym]

In my experince, most firefights depended on accuracy and "getting the drop" on the other guy. Unlike most movies, rifle silencers are not silent, but they reduce the noise enough to make pinpointing your location difficult. They are a combat multiplier and the next generation of Infantry weapons should incorporate them.

 

[PercyShelley]

The shockwave of a sonic boom radiates outwards perpendicular to the direction of travel of the bullet in a manner not unlike cherenkov radiation spreading from the path of an exotic meson traveling through a scintillating medium, to use an esoteric and completely unhelpful simile. Determining the origin of a shot from the bullet's flight noise is in principle possible, you just have to deal with a linear sound source rather than a point source.

In an urban combat situation with lots of buildings each reflecting sound irregularly, I could see the crack confusing the target, but that would be very situational.

 

[nwilliams]

On Future Weapons when they were talking about the Knight's Armament M110 sniper rifle there was mention that one of the military requirements of the new rifle was that it had to have a silencer......

http://www.youtube.com/watch?v=Ql9VCVLDqck

Doesn't really answer your question but I figured I throw it out there

 

[General Geoff]

.300 Whisper. You know you want it.

 

[trstafford]

Concussion Suppression

One thing the suppressor does is to reduce concussion to surrounding team members when doing house entries. It helps protect hearing and the concussion causes trauma to other members.

 

[Tony Williams]

From what I have gathered in talking to some people with experience in the use of suppressed sniper weapons, a suppressor is very useful in concealing the location of the sniper, and is well worth having even with supersonic ammunition.

Subsonic ammunition is special forces stuff, for operations when stealth is a requirement.

 

[Rifleman 173]

Different armies use silencers in different ways. The Isrealis are using carbines in .22LR and 9 mm for urban combat operations. U.S. Navy SEALS used a 9 mm variant called the Hushpuppy to eliminate sentry dogs and geese. In Nam, recon, special ops and scout units used "noise suppressors" to engage enemy personnel in certain operations and certain areas of combat. The idea behind the noise suppressors was to confuse enemy personnel as to the location of where the shot came from and to limit the distance that the shot could be heard. The idea was that in a jungle environment a muffled shot would not be as alarming, in some cases, because the person hearing the shot might think that it originated a long ways off in the distance. It was not unusual for enemy forces to build temporary base camps along jungle trails or in different areas or to put sentries out a ways from their bases. You could eliminate an enemy sentry on OP/LP duty with a silenced .223, drag his body off into the weeds and the enemy might not even think that he had been killed by Americans working in their area. The missing VC/NVA could be accounted for by the communists forces as being "just another AWOL soldier who ran off to go home or be with his wife." The VC/NVA had almost as high a desertion rate as the S. Vietnamese forces and some people would cross back and forth between the two military forces like it was nothing. Until the enemy found the dead guy, they had no idea that he had been actually killed by anybody. Generally, the discovery of the dead guy took about three days or so in the heat of that area.

 

[H2O MAN]

Suppressor Demo

Me and my suppressed Crazy Horse MK14 SEI Mod 0



I wish they have put microphones out in front of me and not behind me.
The whole idea it to confuse people down range.​

 

[Limeyfellow]

This is when you want a DeLisle carbine. Solved all these problems back in WW2 by using a subsonic .45 round, inbuilt suppressor, quiet action that went as far to install a rubber pad to stop the bolthandle making noise as it come to rest, collected cases to avoid noise and was accurate and an effective range of 200 yards (maximum range of 400 yards).

 

[HorseSoldier]

It is extremely difficult to locate the position of a shooter with a suppressed weapon just by the crack of a supersonic round.

 

[Evil Monkey]

It is extremely difficult to locate the position of a shooter with a suppressed weapon just by the crack of a supersonic round.

That's what I figured but other posters offered notion that this may not be the case. Thus, it may be easier to isolate a shooter who's bullet created a supersonic crack rather than one that didn't.

 

[HorseSoldier]

Basically, I'd say a suppressor with supersonic ammunition does everything a suppressor needs to do for battlefield sniping use. Switching to subsonic loads, or specialty subsonic calibers, for sniping is usually only worth the effort for really specialized applications where the increased stealth justifies the decrease in ballistics and performance usually seen with subsonic loads.

 

[3/325]

If you make a successful hit, you're target isn't going to live long enough to ponder where the shot came from.

 

[Zak Smith]

I think if you are listening carefully, you'll be able to hear the buzzing of a subsonic round as it passes you.

A 300gr .338" SMK launched at 1050 fps with a 50-yard zero will need 1.7 mils elevation correction at 100, and 6 mils of elevation correction at 200 yards. 300 yards is almost 11 mils, in other words what a 308 typically needs at 1000-1200 yards.

However, at 300 yards, it has lost only 70 fps from its initial velocity.

 

[Jaenak]

A "silenced" rifle isn't silenced, it just brings the decibel level of the shot down maybe 50 decibels. The shot is still really friggin' loud. A sound suppressor will never eliminate that. Also, a sub-sonic round isn't capable of accurate shooting in even short sniper rifle ranges. Sub-sonic ammo is used only in pistols and sub-machine guns because of it's very low speed, short range, and low knock down power. Even if you do get shot at with a sub sonic bullet, it's not silent either. You can still very easily hear the bullet zip by without even looking for the sound, it simply doesn't make a distinguished crack any longer.

 

[Zak Smith]

Sound suppressors typically reduce the report 20-36 dB.

 

[highorder]

A 300gr .338" SMK launched at 1050 fps with a 50-yard zero will need 1.7 mils elevation correction at 100, and 6 mils of elevation correction at 200 yards. 300 yards is almost 11 mils, in other words what a 308 typically needs at 1000-1200 yards.

However, at 300 yards, it has lost only 70 fps from its initial velocity.

Wow. that's impressive.

 

[Zak Smith]

Well, keep in mind that G1 drag coefficients are probably not totally valid at subsonic velocity.

 

[nfl1990]

Practically speaking, Marcus Luttrell in his Lone Survivor book mentions engaging two Pashtuns at about 100yds across a ravine with his suppressed SPR. The first one toppled into the ravine. The second one heard the shot but couldn't tell where it came from and stood in the same place as the first one.

IIRC he says that the other two guys heard the first guy scream as he fell down the cliff