In response to my last thread

[AICfan1989]

http://www.defencetalk.com/forums/army-security-forces/im-doing-some-research-military-weapons-9651/

This is my last thread but I did not get a chance to post a poll so I hope its OK if I post a new one.

I'm just wondering if anyone in the military has fired both a M4/M16 in 5.56 NATO and an AK-47 in 7.62X39. If so which is louder up close and at a distance?

And is there any noise difference between a civilian .223 and a military 5.56 NATO round?

 

[Bonza]

http://www.defencetalk.com/forums/army-security-forces/im-doing-some-research-military-weapons-9651/

This is my last thread but I did not get a chance to post a poll so I hope its OK if I post a new one.

I'm just wondering if anyone in the military has fired both a M4/M16 in 5.56 NATO and an AK-47 in 7.62X39. If so which is louder up close and at a distance?

And is there any noise difference between a civilian .223 and a military 5.56 NATO round?

I've fired the SKS many moons ago, and civilian .223s, but can't remember how different the sound was due to hearing protection. However I googled up the following links, they may help you:

Noise Levels

Why hearing protection when shooting is important... - Democratic Underground

What is the best way to measure the # of decibels produced by a gunshot? - Yahoo! Answers

I can't vouch for the accuracy of the links but it's all the info I could find. Hope it helps.

 

[the road runner]

Youtube has some great Videos on AK vs M16

The below link is in 3 parts and gives a very good understanding of Ak-47 and M16

[ame="http://www.youtube.com/watch?v=lf6CxQh3YXA&feature=related"]YouTube- Broadcast Yourself.[/ame]

And is there any noise difference between a civilian .223 and a military 5.56 NATO round?

Noise difference,i would think you are splitting hairs here.

Regards

 

[Spetsznaz]

It really depends on which bullet has more kenetic energy that impact the air around the bullets flight path, but thats exterior bellistics and I am not really a pro with that...

 

[AICfan1989]

Does gas pressure effect the noise at all? More pressure means more noise or no?

I wounder how loud the M16 and M4 is compared to the AK-47 in dB levels.

I see they have them for the 5.56 but not for the 7.62.

Also I'm curious as to whether anyone would know how many grains and the type of propellant that the 5.56 NATO, 7.62 NATO and 7.62X39 Russian uses.

Sorry for all the questions I hope this is OK.

 

[Marc 1]

The M16 vs AK-47 noise debate has been done to death elsewhere, so I won't add to that.

The 5.56 and .223 are identical calibres, I have seen and fired 5.56 fired from a 'civillian' Mini14 chambered for .223. No differences, no deleterious effects on the weapon. Same with .308 and 7.62 x 51 - again no differences no ill effects. I was of the belief that any civillian weapon produced in the last 50 years (/ - Whatever a long time anyhow) had a chromed barrel. The only weapons that my old man owned that did not have chromed barrels were a Hollis sidelock 12 guage Bouble barrel shotgun (manufactured around 1900's/1920's?) and a .22 Winchester pump (model 17? maybe?) with an octagonal barrel,again quite old.

The biggest issue with using military ammo in like chambered civy weapons is the fact that you are using solid or ball ammo, whereas when hunting you'd probably more usually use hollow points.

Gas pressure does make a difference, as does barrel length, the type of powder used and grain size etc. There are a whole stack of things that influence the noise you hear. As a very rough rule of thumb, the shorter the barrel the louder the report, the 'steamier' the load the louder the report (you can load various projectiles with varying amounts of powder behind them - generally, the faster the muzzle velocity the louder the report).

I'm no expert on this and the last time I did any handloading was 25 years ago. I'm sure one of the small arms experts can help though.

 

[AICfan1989]

The M16 vs AK-47 noise debate has been done to death elsewhere, so I won't add to that.

The 5.56 and .223 are identical calibres, I have seen and fired 5.56 fired from a 'civillian' Mini14 chambered for .223. No differences, no deleterious effects on the weapon. Same with .308 and 7.62 x 51 - again no differences no ill effects. I was of the belief that any civillian weapon produced in the last 50 years (/ - Whatever a long time anyhow) had a chromed barrel. The only weapons that my old man owned that did not have chromed barrels were a Hollis sidelock 12 guage Bouble barrel shotgun (manufactured around 1900's/1920's?) and a .22 Winchester pump (model 17? maybe?) with an octagonal barrel,again quite old.

The biggest issue with using military ammo in like chambered civy weapons is the fact that you are using solid or ball ammo, whereas when hunting you'd probably more usually use hollow points.

Gas pressure does make a difference, as does barrel length, the type of powder used and grain size etc. There are a whole stack of things that influence the noise you hear. As a very rough rule of thumb, the shorter the barrel the louder the report, the 'steamier' the load the louder the report (you can load various projectiles with varying amounts of powder behind them - generally, the faster the muzzle velocity the louder the report).

I'm no expert on this and the last time I did any handloading was 25 years ago. I'm sure one of the small arms experts can help though.

I had no idea the 5.56 vs 7.62 noise has been discussed here before.

Based on your observations, what do you think is louder, 5.56 or 7.62X39?

Also so there is no noise difference between a 5.56 NATO round and a civ .223?

However I wonder what causes the military round to have a high gas pressure if its the same round, is it the powder?

 

[Bonza]

I had no idea the 5.56 vs 7.62 noise has been discussed here before.

Based on your observations, what do you think is louder, 5.56 or 7.62X39?

Also so there is no noise difference between a 5.56 NATO round and a civ .223?

However I wonder what causes the military round to have a high gas pressure if its the same round, is it the powder?

Just out of curiosity, why do you need to know this so badly? I'm just wondering as you seem very concerned as to the answer and it's not a detail I've seen other people ask about in depth.

 

[Marc 1]

I had no idea the 5.56 vs 7.62 noise has been discussed here before.

Yep, use the search feature.

Based on your observations, what do you think is louder, 5.56 or 7.62X39?

Not sure/can't remember. I do remember the report of the AK47 was different to the SLR or M16 that Australia was using at the time.

Also so there is no noise difference between a 5.56 NATO round and a civ .223?

Depends on the powder load, the projectile etc. Different brands of ammunition have different signatures - most are barely distinguishable to the human ear, some 'slow or light' loads will sound different to the faster or steamier loads.

However I wonder what causes the military round to have a high gas pressure if its the same round, is it the powder?

Confused by what you mean by gas pressure. Are we talking the gas system on an automatic or semiautomatic weapon or are you talking about chamber pressure? Who said a military round had high gas pressure? I'm pretty certain you can buy civy .308 and .223 ammo that throw the same weight projectile at similar velocities from similar length barrels - ergo the chamber pressure would be roughly the same.

Don't be thinking that just because 7.62 x 51 is a military round that it must be faster, harder hitting and have a longer range than its civvy equivalent - .308. Remember many of these calibres and rounds were civvy before being adopted by the green machine.

 

[AICfan1989]

Confused by what you mean by gas pressure. Are we talking the gas system on an automatic or semiautomatic weapon or are you talking about chamber pressure? Who said a military round had high gas pressure? I'm pretty certain you can buy civy .308 and .223 ammo that throw the same weight projectile at similar velocities from similar length barrels - ergo the chamber pressure would be roughly the same.

Don't be thinking that just because 7.62 x 51 is a military round that it must be faster, harder hitting and have a longer range than its civvy equivalent - .308. Remember many of these calibres and rounds were civvy before being adopted by the green machine.

I'm talking about the chamber pressure when the round goes off.

The 7.62X39 is rated at max PSI of around 51,000
The civilian .223 is rated at 55,000 Max PSI
The military 5.56 NATO is rated at Max PSI of 62,000 and is labeled as 'hotter' or 'steamier'.

And I was just wondering what causes the different in the two rounds.


On a different note I found this video of both the M249 SAW and M240 firing, it sounds like good sound quality to me, do you think it sounds like this is real life?

[ame="http://www.youtube.com/watch?v=697CfQX2xBk"]YouTube- Broadcast Yourself.[/ame]

I have noticed the M240 is only slightly louder, the M249 is not far behind as both weapon echo a lot in this video. Best quality I could find but sounds great to me though.

 

[Marc 1]

I'm talking about the chamber pressure when the round goes off.

The 7.62X39 is rated at max PSI of around 51,000
The civilian .223 is rated at 55,000 Max PSI
The military 5.56 NATO is rated at Max PSI of 62,000 and is labeled as 'hotter' or 'steamier'.

And I was just wondering what causes the different in the two rounds.

Powder charge and the type of powder used. More powder causes more pressure (as can a blocked barrel). I stand corrected on the 5.56 vs .223 comparison though - the 5.56mm cartridge has a thicker case to allow the higher pressures - although there is not that much of a difference, and I dare say a civvy reloader could get equal results out of a .223 in a bolt action if he so desired. I have seen a double quantity of powder added to a .222 accidentally, (so a massive overloading) and thanks to the strength of the Sako bolt action the only reason it was noticed was that the report and recoil was greater and there was a little more difficulty in extracting the spent case.

This answer here seems to give good info: AR-15 5.56 Vs. .223 What the different? - Yahoo! Answers

Note where he states the Mini 14 has no issues with firing the 5.56 rounds - that was the weapon I had used with both.

The ideal powder burns and provides acceleration to the round the whole length of the barrel. By the time the cartridge has reached the end of the barrel the powder ideally should be fully combusted. In pistols and other short barrelled weapons the barrel is much shorter, so the powder must burn much faster as the round leaves the muzzle sooner.

On a different note I found this video of both the M249 SAW and M240 firing, it sounds like good sound quality to me, do you think it sounds like this is real life?
.

The cyclic rates sound different, but its otherwise difficult to distinguish which is louder due to the camera automatically adjusting levels.

 

[AICfan1989]

Powder charge and the type of powder used. More powder causes more pressure (as can a blocked barrel). I stand corrected on the 5.56 vs .223 comparison though - the 5.56mm cartridge has a thicker case to allow the higher pressures - although there is not that much of a difference, and I dare say a civvy reloader could get equal results out of a .223 in a bolt action if he so desired. I have seen a double quantity of powder added to a .222 accidentally, (so a massive overloading) and thanks to the strength of the Sako bolt action the only reason it was noticed was that the report and recoil was greater and there was a little more difficulty in extracting the spent case.




The cyclic rates sound different, but its otherwise difficult to distinguish which is louder due to the camera automatically adjusting levels.

Ah I understand now o the 5.56 vs .223.

As for the video I could tell the M240 is slightly louder but the M249 is still almost as loud.

But then again like you said the cameras mic was changing the level so it could be hard to tell unless the camera has its setting on a fixed noise level.

 

[AICfan1989]

I was told that the sharper crack sound of the 5.56 carries farther and sounds louder at a distance than the 7.62x39, is that true?

Anyone know?