In the thread about “open tip bullets…” DocGKR questions as to why there is so much concern about how loud some new 7.62 loads are. He points out that they’re ALL loud and if it bugs you the option of a suppressor is there. As usual, he is correct, but perhaps the correspondent had some of the same issues I had. My 16 inch .308 was really unpleasant to shoot, even with ear plugs, and a suppressor wasn’t my solution because of local regulations and the desire to keep the weight and length under control. It surprised me that my 18 inch FAL was less abusive than my 16 inch AR-10 and totally useable with just soft foam earplugs. Who would have thought 2 inches could make so much difference (mind out of gutter, please)? I didn’t want to even think of firing my AR in an enclosed space without headphones on. I finally put a Noveske KX3 on the AR and the problem seems solved, for my purposes anyway. I wonder about the professionals who use the shorter barreled 7.62’s out there without suppressors. Are the conventional flash suppressors they come with useful in reducing the pressure waves that bug me so? Do they just man up and deal with the muzzle blast and hearing loss? Don’t leave the house without headphones? Am I just “too sensitive”? I would like to hear from the folks who would know.
This is a thread I’ll be following closely, as my 16" BM is just as loud as my 10.5" AR pistol. Well, as far as I can perceive anyhow. Yes I always use ear protection.
The battlefield is a noisy and dirty place.
Yes, we issue all kinds of hearing protection. Given the time, put in/on before shooting or blowing shit up. If you’re being blown up or shot at yes, you have other things to contend with at a particular moment in time.
Not all Soldiers are issued suppressors. Damn near all of them carry some sort of rifle, carbine, or pistol with which to defend themselves. I think most all go bang when you pull the trigger. Yes, the bang can damage your hearing if you don’t have some kind of ear defender in/on.
I truly don’t want to sound critical or sarcastic but noise is a function of firearms – whether it’s a 16-inch 7.62, a 14.5 M4, a Minigun, or anything else that uses US military small arms ammunition.
What flash hider or compensator do you have on your Bushmaster?
I have shot some a friend’s Bushmaster with the AK style comp and it was painful. It made me want to go back and put earplugs under my muffs.
Wow, less caffeine Sinister. Yup, I know “Needs must, when the Devil drives”. I have the military hearing loss to prove it (20+ years ago). I have the luxury of choosing my weapons these days. A lot of muzzle blast affects MY shooting. I wonder what those who now do this for a living have experienced. So, for those who might know better than I, would you choose an un-suppressed 16 inch or, if you were the Grand Poohbah, specify a little longer? It’s a technical question on a technical forum.
The Bushy sports a YHM Phantom, with six ports, the pistol has a standard A2 Birdcage.
It truly does come to physics. If your mission drives a requirement for a short 7.62 (or whatever – call it a 5.56, 50, or 338) and you want to shoot it fast you’re either going to need a brake, a compensator, or suppressor – but with that there’s no free lunch.
Anything venting to the side means a shock wave originating perpendicular to line of bore – meaning the sound is going to be as if someone’s shooting a rifle at your 9 or 3-o’clock the distance of the brake ports from your ears.
Original XM-177 carbines had the noise/flash suppressor that dropped the noise only a couple decibels – hardly much of an improvement. The drive to 12.5-inch (and shorter) carbines is meant to meet perceived mission requirements and size envelopes and not hearing considerations.
I’m not sure any of our weapons has been designed with noise/blast consideration until you start looking at blast sickness (I know they put the flared muzzle on the Super 81mm mortar because of the blast wave, but I don’t think anything’s ever been done like that for small arms).
When you just get home from 8 hours at the hospital, seeing this can really give you a laugh!
I don’t know that the .308 has sounded any louder to me. I think XM193 is about equal to the .308, although the .308 is deeper, and more of a “boom” and the XM193 is more of a blast/crack.
After a quick run through google, I found that both the M4, and an FN, FAL, produce roughly 155-165db, depending on distance/angle from muzzle, etc. measured.
All unsuppressed centerfire rifles are loud. Barrel length and powder burn rates are a factor. Flash suppressors, muzzle breaks, and compensators all direct the muzzle blast in different ways. Don’t confuse blast and concussion, with the actual dB’s of loudness. I ALWAYS keep ear plugs in my pocket and electronic hearing protection in my gear bag, range bag, and next to my helmet.
I recall reading a several years ago that .mil way looking the possibility of going across the board suppressors for small arms. I am guessing getting into a shooting war derailed this.
Would this be a good way to go for medical as well as tactical reasons, or are there enough other noises that it would just add to maint. and add no real advantage?
Asked by the guy with a perforated eardrum and 30% lost in the other ear. Thanks to drag racing more than anything else :o
I had to shoot a FAL with 21 in barrel (combidevice) in a shoot house once. We were handed cotton for our ears:eek: It was most unpleasant… glad I had to only do it once:p
I think Hop has used a 16in FAL for shipboard work and he may have some insight here.
Typically a 5.56 mm assault rifle is 165-167 dB, measured 1 m left of the muzzle as according to MIL-STD 1474D.
With modern suppressors the net sound suppression at the muzzle is c. 20-34 dB, leaving a suppressed level of c. 133-145 dB.
Usually the SPL at the shooters ear with 5.56 mm calibre weapons is c. 132-142 dB, getting louder usually as the barrel shortens…
With 7.62mm calibre semi-auto / assault rifles, the muzzle suppression figures are quite comparative, but our experiences have been that it is harder to get below the 140 dB threshold at the shooters ear with these weapons ( Weapon examples to include the FN FAL, G3 and HK417 )
So our approach has been to make the 7.62 mm assault rifle suppressors as small as possible, but still providing a good level of muzzle SPL and flash suppression.
PS. Sinister, the GSG-9s have been put to good use…
Best Regards!
Tuukka Jokinen
Ase Utra sound suppressors
