Hard Data on Suppressed Barrel length & Volume (5.56/.223)

[BigWoods]

I initially posted this over on the suppressor side, but thought I'd post it here as this forum gets a lot more traffic.

Well I finally have my ab a-10 in hand for my Howa Mini in .223. As expected, with the 22" barrel it is somewhat unwieldy and front heavy. Balance point is well up the fore end of the stock. It feels awesome on my 16" 10/22.


With that, I've been intending to cut this rifle down to 16" or so. My question is, which I haven't seen any hard data on, is what measurable effect will that have on decibels at shooters ear?

The best I've seen after a fair bit of looking is a subjective "not much of a difference." This will primarily be used for training my kids and their deer hunting. The more hearing safe the better. Obviously at the range, I still intend to use plugs or muffs, but that's more impractical in our context out hunting. My understanding is that suppressed, I'll be right on that edge of hearing safe and I'd like to keep it there.

What should I know? Thanks for the help!

 

[StupidLightweight]

I can't give you hard data, but it will be slightly louder because the supersonic crack of the bullet is closer to your ears. Is it a .223 can? If not, do you have a .223 endcap? That will be more important than barrel length.

Regardless, I wouldn't worry about increased noise from a 16-inch barrel with a suppressor. I'm a nazi when it comes to hearing protection, but I don't sweat a few suppressed shots at game. Your kids will lose more hearing from loud headphones than shots in the field with a suppressed .223.

 

[BigWoods]

I can't give you hard data, but it will be slightly louder because the supersonic crack of the bullet is closer to your ears. Is it a .223 can? If not, do you have a .223 endcap? That will be more important than barrel length.

Regardless, I wouldn't worry about increased noise from a 16-inch barrel with a suppressor. I'm a nazi when it comes to hearing protection, but I don't sweat a few suppressed shots at game. Your kids will lose more hearing from loud headphones than shots in the field with a suppressed .223.

Ok that's really helpful perspective! I hadn't thohlught about the distance from the sonic crack. That makes sense. But, with the suppressor already making the rifle ~3 magnitudes quieter, a couple decibles different from barrel length will be a very minor danger compared to unsuppressed.

It is a 308 can so I might be loosing a bit there. I have a b&t TiGer 22 in jail that I'll experiment with on this rifle. Who knows, it may find more of a permanent here. A 4oz, 5" can on here would be fantastically handy.

 

[RWT]

I doubt you will find hard data as the
difference in barrel length and suppression are as varied as the atmospheric conditions that influence sound. Wind direction and humidity can change a perceived sound by a few db’s. I’ve had hot ammo be noticeably louder in the same system.

Double up on the ear pro. Foamies or Decibels in the ear and some form of over the ear protection is all you can do for them.

 

[Q_Sertorius]

I use a 7.62 caliber AB Raptor 10 with 5” reflex on a 16.5” .223 and it’s stupidly quiet. I also have an AB Raptor 8 with 3” reflex and, while not as quiet, it’s still very quiet. Anytime you are at the range, you should be wearing hearing protection anyway. This gives you a redundant system that protects your hearing as required for an extended shooting session.

 

[BigWoods]

I use a 7.62 caliber AB Raptor 10 with 5” reflex on a 16.5” .223 and it’s stupidly quiet. I also have an AB Raptor 8 with 3” reflex and, while not as quiet, it’s still very quiet. Anytime you are at the range, you should be wearing hearing protection anyway. This gives you a redundant system that protects your hearing as required for an extended shooting session.

Indeed, other than maybe supressed 22lr, I intend to keep earpro for me and the crew even with suppressors.

 

[Q_Sertorius]

Indeed, other than maybe supressed 22lr, I intend to keep earpro for me and the crew even with suppressors.

An hour of suppressed, subsonic .22 LR is like an hour at a rock concert.

If I am at the range, I have earplugs in, headphones on, and a good suppressor. Assuming perfect fit and wear, that’s taking a .308 from 160-165 dbA down to about 80-90 dbA.

 

[Chris in TN]

My centerfire cans are less efficient than the can you're looking at, and all I can say is that I have the kids wear ear pro unless we're hunting, and I have ear pro with them when we are hunting, and they have the option to wear it or not depending on how the shot plays out, and I do not worry, in the least, about a single shot from a 16" 5.56 with a less efficient can. I never want to go back to shooting unsuppressed, certainly not without ear pro, but I think the OP is overthinking this. One shot here and there will be fine.

 

[BigWoods]

An hour of suppressed, subsonic .22 LR is like an hour at a rock concert.

Wow that really puts things into perspective! Really wish I could take back those years of qualifying permit to carry students at an indoor range with just foamies in. The headaches afterwards should have been an indicator ....The time a guy mag dumped next to me and a student with a braked FN SCAR was absolutely stunning.

 

[BigWoods]

My centerfire cans are less efficient than the can you're looking at, and all I can say is that I have the kids wear ear pro unless we're hunting, and I have ear pro with them when we are hunting, and they have the option to wear it or not depending on how the shot plays out, and I do not worry, in the least, about a single shot from a 16" 5.56 with a less efficient can. I never want to go back to shooting unsuppressed, certainly not without ear pro, but I think the OP is overthinking this. One shot here and there will be fine.

Hey isn't overthinking what we're all here for? But again that's helpful experience that you bring to the table!

Going to drop the rifle off for a chop tomorrow.

 

[Chris in TN]

Hey isn't overthinking what we're all here for? But again that's helpful experience that you bring to the table!

Going to drop the rifle off for a chop tomorrow.

I mean, it's good to think this out, and I absolutely want my kids to protect their hearing better than I did - but I'm 50 and still hear well with no REEEEEEEEEEeeeeee. I also make them wear bike helmets and make them not ride around standing on the axle of my tractor the way my grandpa did with me on his tractors (while plowing and mowing, even) and....ehhh, you understand the point.

 

[North of 60]

Most folks without hearing issues (or having not had someone close to them experience it from noise) are less likely to as concerned about noise-induced hearing loss than those of us with it. Ringing ears from shooting was part of the deal for many of us who grew up without earpro.

I've been doubling up (ear plugs and muffs) since the late 80s when test firing weapons was part of my job then and already had noise-induced hearing loss from the many, many shots fired prior to that.

Unlike me, my son who has fired thousands of rounds with earpro likely will not have that issue thank goodness.

I'm grateful suppressors are more available/lighter as they wonderful to reduce risk of hearing damage.

 

[StupidLightweight]

An hour of suppressed, subsonic .22 LR is like an hour at a rock concert.

Q, Am I reading this right: An hour of .22 LR shooting is equivalent to one hour's worth of hearing damage from a concert?

If so, that's shocking. Manually-operated rifles with subs and a can sounds to my ears like I could shoot them indefinitely without damage.

 

[ElPollo]

My 18” Tikka is doing 2750 fps with Black Hill 77 TMKs. That gives me about a 450 yard limit to keep my impact velocity above 1800 at my normal DA. If I had it to do over again I would go 16”.

The A-10 is a great can.

 

[5MilesBack]

Q, Am I reading this right: An hour of .22 LR shooting is equivalent to one hour's worth of hearing damage from a concert?

If so, that's shocking. Manually-operated rifles with subs and a can sounds to my ears like I could shoot them indefinitely without damage.

The only thing I hear with subsonics is the click of the bolt. More like never being at a rock concert.

 

[BigWoods]

Q, Am I reading this right: An hour of .22 LR shooting is equivalent to one hour's worth of hearing damage from a concert?

If so, that's shocking. Manually-operated rifles with subs and a can sounds to my ears like I could shoot them indefinitely without damage.

I do wonder if that's not a direct equivalent. I know steady state noise of say 120+db is more damaging than instantaneous pulls sounds of the same volume. A rock concert as a continually high volume. Shooting is a series of pulses...you'd have to continually mag dump for an hour and even then, the total time of noise would be much less. Am I thinking straight here?

 

[omicron1792]

I haven’t found end caps to make any difference. I think the data backs that up too.

 

[Q_Sertorius]

Q, Am I reading this right: An hour of .22 LR shooting is equivalent to one hour's worth of hearing damage from a concert?

If so, that's shocking. Manually-operated rifles with subs and a can sounds to my ears like I could shoot them indefinitely without damage.

Yes, that’s close to the same decibel level. Our ears need time to recover from the sound impulses. I am not talking about continuous magazine dumps either. A suppressed .22 subsonic from a bolt action is in the 110-120 decibel range. If you value your hearing, you don’t want to expose your ears to extended unprotected sessions of those impulses.

Of course, “a rock concert’s volume” also varies depending on environmental factors and your location, but OSHA generally regards a generic rock concert as 100-120 decibels. That’s enough noise for the potential for hearing loss in as little as 15 minutes of exposure. Near the stage at an AC/DC concert might be more like 130 decibels.

 

[Q_Sertorius]

I do wonder if that's not a direct equivalent. I know steady state noise of say 120+db is more damaging than instantaneous pulls sounds of the same volume. A rock concert as a continually high volume. Shooting is a series of pulses...you'd have to continually mag dump for an hour and even then, the total time of noise would be much less. Am I thinking straight here?

It’s not so much that the series of shooting pulses is worse or better as that concerts, particularly indoor ones, are spectacularly loud compared to natural environmental sounds. Our ears are not made for that. When I refer to it being louder than a rock concert, I am using the rock concert as an example of something that will hurt your hearing if you don’t protect yourself.

There’s a reason that Beethoven was deaf by the time he composed his famous 9th symphony.

Our ears need time to recover from the sound impulses. A continuous high volume sound can do as much damage as a spaced out higher volume sound.

 

[Q_Sertorius]

I haven’t found end caps to make any difference. I think the data backs that up too.

The data supports that they make only a very marginal difference. The overall bore diameter of the suppressor makes more of a difference, particularly with shorter suppressors.