On my weekly trip to the gun shop, I happened to peruse the shelves and noticed a few boxes of American Eagle Suppressor ammo in .45. Intrigued, I picked the box up and noticed that it was proudly advertised as “subsonic” and “made for suppressor use.” I turned to the OFWG behind the sales counter with the box in my hand and said, “But isn’t all .45 ACP subsonic?” He said, yes it is. “Okay then,” I said, “so what the heck is this stuff?” Â “Well, that’s even better and quieter than regular .45 ACP.” Mmmmkay. Now, I may have been born at night . . .
But it wasn’t last night. This smelled like a shameless attempt to cash in on the suppressor craze to me, particularly as this ammo had a price tag of $35 for 50 rounds. That’s at least 50% more than regular FMJ .45 ACP was currently going for and nearly twice what I paid for .45 ACP not that long ago.
Since I happen to own a .45 silencer, I figured that I owed it to the community to pick up a box and test out the claims. Â Before we delve into things, though, let’s take a quick look at the science of sound suppression.
To oversimplify things, there are generally two major elements to the noise that a bullet makes. The first component is the noise made by the bullet leaving the barrel. This is largely the work of the high temperature and pressurized gas that leaves the barrel behind the bullet. Both of which ares directly related to the amount of powder used to propel the bullet. This explains why a .45 is louder than a 9 mm, and that’s louder than a .22. And a rifle is generally louder than any pistol round. Â It’s also why suppressors tend to get longer and/or fatter as you move up in caliber. That’s this component of noise that the suppressor has the greatest ability to control.
The second element of noise is the sonic boom of the round makes as it breaks the sound barrier, which happens at about 1,125 feet per second at sea level. Most types of ammo exceed this speed fairly easily. The relatively slower moving 230 grain standard .45 ACP does not (although there are some lightweight defensive rounds that can exceed the speed of sound in .45).
So, it was off to the range with a box of this American Eagle stuff, a box of Blaser FMJ .45, my Advanced Armament Company TiRant .45 suppressor (not pictured below), and my H&K USP Tactical.
I set up my chronograph as I wanted to see if there was any significant velocity difference between the Blaser and the American Eagle ammo. I loaded up one magazine of Blaser and one of American Eagle. For my third mag, I alternated between Blaser and American Eagle so that I could compare the two back to back. The ambient temperature on the range that day was 27 degrees and the humidity fairly low. According to the chronograph, the Blaser had an average velocity of 875 feet per second with a standard deviation of 6 while the American Eagle suppressor ammo clocked in at about 852 feet per second with a standard deviation of 11.
What about the noise level? Unfortunately, I don’t have the kind of equipment necessary to properly test suppression levels. The sort of stuff you need to measure things as short in duration as a gunshot doesn’t come cheap. What I do have, though, is two highly efficient organs on the sides of my head that are sensitive enough to hear my kids talking upstairs after bedtime.
Using these less-than-scientific devices, I came to the conclusion that there was no appreciable difference between the cheap Blaser FMJ and the much more expensive American Eagle Suppressor stuff. This became especially apparent when I got to the magazine where the two types of ammo alternated. I simply could not tell the difference in sound level. The Blaser seemed to have slightly more bass in its report, but in terms of how loud the two rounds sounded, there was no discernible difference. Certainly nothing to justify that price. Pretty much what I expected.
That evening, I went onto American Eagle’s site and read the following description of their suppressor ammo:
Available for rifle, handgun and rimfire. Turn down the volume without sacrificing performance. American Eagle® Suppressor delivers superior accuracy, reliability and cleanliness in suppressed firearms, thanks to carefully selected propellants, bullet weights and profiles. The subsonic loading lends themselves to better noise reduction through the suppressor, and they also reduce noise by avoiding the ballistic crack inherent to supersonic loads. In addition, special clean-burning powders make cleaning weapons easy for shooters—other conventional ammunition can cause severe fouling in suppressed firearms.
I can see this ammo making a difference in any round that’s normally supersonic, such as 9mm or .22 (not to mention most rifle rounds). But it really doesn’t bring much to the table when you’re talking about something like .45 ACP that’s already subsonic. As for the rest of the claims, “special clean burning powders,” the only way to really measure the truth about that is to shoot a couple of boxes through my H&K, then compare the level of filth with normal ammo. If Federal Premium wants to send me a box or two, I’m game, but otherwise, I think I’ll hang onto my cash.
Bottom line: Don’t waste your money on the .45 flavor. Other sizes TBD.
I’ve tried the 124gr 9mm and I LOVE it. Very clean burning, very accurate, so far has been very reliable, and at $17.50 for a box of 50 it wasn’t half bad in price. I wish the store I got it from would get more in.
In 9x19mm, why not just use 147gr ammo? Is there any advantage?
Well, availability and price. 147gr subsonic is nearly impossible to find at a good price right now.
Everything else being the same (power level), lighter ammo does have less felt recoil.
124 grain 9mm is often supersonic, though, out of a pistol barrel. This stuff must be loaded a bit on the light side to ensure that it’s subsonic through a full sized pistol plus a suppressor (which adds velocity).
While a suppressor does technically constitute a lengthening of the barrel, the nature of the beast – trapping gasses and dissipating them slowly – make for very little in the way of added projectile velocity.
Felt recoil tends to be a reflexion of power, and is similar therefor for x weight at y velocity and x/z weight at y•z velocity. I think you meant lighter projectile at the same velocity rather than the same power.
EDIT: I will grant, however, that a rapid tap from the stock rather than a heavy shove – even if comprising the same number o’ Newtons o’ force – might feel lighter.
Yeah, even at the same ft-lbs of energy loading or with the same powder charges in each load, most people will find the lighter bullet to have less felt recoil. In fact, some of the really hot but super light self defense loads advertise light recoil and low muzzle flip and that is usually the case, even if you’re comparing a 50-grain 9mm load making 440 ftlbs to a 124 grain 9mm load making 385 ftlbs. This can be outside of physics equations and what it says on paper, as felt recoil can be subjective. It just happens that nearly everyone will agree that shooting 115 grn is softer than 124 is softer than 147, even if they’re all the same brand of ammo or you hand load all of them with the same powder charge, etc. I think it’s even easier to feel with a bolt/lever action rifle, though. For instance, both remington and winchester (and probably others) make 150 grn and 170 grn .30-30 loads in the same brand. Typically the 150 grn load makes a bit more ftlbs of energy but it clearly kicks less and I don’t think anyone would debate it shooting them back-2-back.
…but you have to keep comparisons inside the same caliber, because pressure differences and other things between calibers can throw a complete curveball in that (e.g. 230 grn .45 ACP has less felt recoil for many people than 180 grn .40 S&W… but keeping in the same caliber, 185 grn .45 is going to kick less than 230 grn for most people)…
I saw around 2% increase in velocity with the suppressor vs without. With some of the ammo I shoot (especially .22) hovering right around the speed of sound, the additional 25 fps can put it over. Sometimes when shooting .22 out of the pistol, one or two rounds out of the magazine will go supersonic and the rest are subsonic. It’s right on the cusp.
I know this is an older post, but given same powder levels, same gun/barrel length, and all else being equal, wouldn’t the 150 gr bullet have less ft/lbs of energy than the 170 gr? Which is the reason felt recoil is less?
The ambient temperature on the range that day was 27 degrees
You must live in Cuernavaca or something. We haven’t seen 27 in New England since — say, what year is this anyway?
Judging by the headlines of the last few days, I’m going with 1984.
Celsius?
Winchester now offers “Special” 1911-specific .45 ACP 230-gr. ammo in both ball and HP configurations. Isn’t that special?
My 1911 will eat damn near anything (something Remington actually did right). So unless they unearthed John Browning’s original prototypes for the .45 I’ll stick with cheap….
BUSTED…;)
Pretty much every flavor of factory .45 ACP is sub-sonic until you get down to about 185 grains. I’d pass, too.
“This smelled like a shameless attempt to cash in on the suppressor craze to me…”
But they got your money anyway. ATK FTW 😉
Hey, can’t knock it ’till I’ve tried it.
Haven’t tried homosexuality, bog snorkeling or tripeburgers, but plan to give ’em a clean miss anyway.
+1
I don’t think homosexuality is something you “try.” You “try” ice cream.
It’s probably enclosed based bullets as well. Lead vaporization is what causes the biggest buildup of carbon and crud on cans. Any good ammo built for cans should be enclosed base.
Caveat: haven’t read entire review yet. Will do so later this evening.
Elevation doesn’t actually affect the speed of sound. It’s temperature that does. Handy calculator on this page: http://www.sengpielaudio.com/calculator-speedsound.htm
It has come into play for me a few times with some .22 lr loads, specifically, that hover right around the speed of sound and are subsonic for me when it’s warm out and supersonic when it’s cold 🙂
I made this video back when I first got my Liberty Mystic suppressor, and the volume difference between supersonic and subsonic 9mm ammo is HUGE. The sonic boom of the bullet breaking the sound barrier is really loud. http://youtu.be/U_yhqnfSjXA?t=5m7s
Altitude doesn’t affect the speed of sound? Granted it’s rather finely granular at the altitude variance of the US, but so are gravity readings. You might want to consult every aero engineer and person who flies planes near the sound barrier. .
http://www.tscm.com/mach-as.pdf
That link starts out by saying, “since the temperature and pressure of air decreases with altitude, so does the speed of sound.” But, when speaking of altitude it’s really only the temperature that changes the speed of sound, as lower pressure increases the speed of sound but lower density decreases it. The changes in pressure and density are proportional and cancel each other out, and you can see that in the equation for speed of sound where pressure is divided by density. This is why all of the math mentioned in the link you posted uses temperature as a variable and speaks of altitude in terms of temperature (standard temp at sea level. standard temp at altitude). Instead of plugging in altitude as the variable, they plug in the temperature.
It’s only because temperature changes in a predictable and reliable way once you start getting to a certain altitude that we are so often led to believe that the speed of sound changes because of altitude. Which, yeah, it does, but it’s only because of the temp change unless you really want to get down into the minutia where pressure & density don’t exactly cancel out so there is a teeny little affect. Humidity has a larger effect as a variable than altitude exclusive of temperature changes.
But, YES, if you are on a 10,000 ft high mountain peak and it’s 70 degrees out you would measure the speed of sound as being THE SAME as when you are at sea level and it’s 70 degrees out.
Read the link I posted.
I don’t give two good flyins about whatever casserole of nonsense you cited, anymore than a cite that says the Earth is 6000 years old, or that humans co-existed with dinosaurs.
It’s either absolute rubbish, or you don’t truly understand what it’s saying. So, at you could heat atmo at 10 kPa to some Earth-seen temp point that it would be the same as 70F at 100 kPa? Lemme guess, you think gravity is the same everywhere on the planet too? And some wonder why we’re 22nd in the world (and continuing to fall) in science education.
That altitude changes MACH is 100% established science up there with our solar system being heliocentric.
You only have the causality backwards. Altitude does change the speed of sound, but only because the temp changes. Like I said, though, pressure and density don’t perfectly cancel each other out so there is some affect that altitude alone has. If you are the type to think that the differences in gravitational pull in various places and altitudes on earth matter for your shooting then you win. You’re right.
Sorry I linked to some random site. Here’s NASA corroborating. http://www.grc.nasa.gov/WWW/k-12/VirtualAero/BottleRocket/airplane/sound.html
This slide show is also good, because it gets right to the equation showing that temperature is THE variable. Which was also in the PDF that you linked to: http://wiki.answers.com/Q/How_does_mach_number_vary_with_temperature_and_altitude?#slide=1
“That altitude changes MACH…” BTW altitude (nor temp) doesn’t change Mach. Mach is relative and Mach 1 always equals the speed of sound. At any altitude and any temperature, Mach 1 = speed of sound. So it never changes. What changes is the speed of sound.
I’m so sorry the educational system failed you, but it’s no reason for me to sanction scientific ignorance. I gave you an honorable ‘out’ with the granularity statement. It’s a shame you didn’t take it, but like global warming deniers, you’re apparently stuck on some data that you really don’t understand or choose to somehow misinterpret.
The bottom line is that as altitude increases, there are fewer molecules of atmo to excite. I would offer PV=nRT which is what we call The Ideal Gas Law for starters, then if you can eventually grasp that move on to the rest of what the Air Force and NASA have known for decades – short of heating that will never happen on planet Earth, MACH varies by altitude. Until we start turning 1kPa atmo into a plasma, it does not behave as 100kPa at 70F.
Our missiles are incredibly accurate because NGA via DMAAC sends guys out all around the world to measure gravity differentials. Those flight calcs also factor altitude, which has a programmed link to velocity and MACH – just not the one you want it to be.
Ke-reist, I don’t believe this.
16V, give it up. Apparently in [Unicorn and Jeremy S] land, the only thing that changes atmospheric pressure is temperature.
Il’l just remember the next time I’m at 20,000 feet in an unpressurized aircraft, it’s 80° warmer outside than when I wintered at the south flippin’ pole and the air is a whole lot thinner that it’s all in my mind.
Just goes to show that a bit of education doesn’t necessarily eradicate ignorance or stupidity. Don’t know which applies to J S, but it’s at least one of the two.
“[in Jeremy S land] the only thing that changes atmospheric pressure is temperature”
Holy crap I never said that. In fact, it’s quite the opposite and the reason that temperature drops as you increase in altitude is due to the drop in atmospheric pressure. This I understand. This doesn’t change anything. All I said is that air temperature is what changes the speed of sound through the air, NOT altitude. You guys aren’t even looking at the math to see that the equations for speed of sound in air all use temperature as the variable, not elevation (and when calculators use elevation it’s only because they have assigned standard temperatures to each elevation, allowing you to say “30,000 ft” when what you’re really saying is “-49* F”). Read the dang NASA link:
“The speed of sound depends on the temperature, and temperature changes with altitude in a very complex way. Engineers have created a mathematical model of the atmosphere to account for the effects of altitude on the temperature.” and “The Mach number depends on the speed of sound in a gas. The speed of sound in air depends on the temperature which, in turn, depends on the altitude in a rather complex way.”
Did you read the very simple Wiki thing?:
“Mach no. is dependent on ambient air temp which is associated with a given altitude. As one ascends the temp drops so does the mach no.
Eg. In a standard atmosphere (ISA – international std atmosphere) sea level temp is 15 degrees C or 59 degrees F. Temp decreases at 2 degrees celcius per 1000′ therefore for example, in a standard atmosphere the temp at say 30000′ would be:
15C at 0′
-45C at 30000′
Plug that into the equation to find the Local Speed of Sound (LSS) which is:
LSS = 38.945 (square root of)/ Outside air temp + Absolute temp being 273A or 273K
LSS = 38.945 x 228
LSS = 588 kts at 30000′
So if one is doing 480knots at 30000′ on a standard, day they are doing 480/588 = Mach0.82”
In the dang link that 16V posted himself, it makes it VERY clear by showing the equations that use only temperature as the variable and in comments such as this:
“The speed of sound calculated from this formula can be used with the equation on the first page to obtain Mach number. This equation uses the standard sea level temperature of 59* F and a lapse rate of -3.57*/1000 ft altitude. Temperature stabilizes at -69.7* F at 36,000 ft so the speed of sound stabilizes there at 573 knots.”
What is that, temperature is stable and therefore the speed of sound is stable? Yeah.
I understand that you’re now going to say, “altitude drives temperature, temperature drives speed of sound, therefore altitude drives speed of sound.” I get that, but it’s temperature that drives the math and temperature can change without altitude changing. If alt changes but temp doesn’t, the speed of sound stays the same. If temp changes but alt doesn’t, the speed of sound changes. TEMP is the factor, period.
I know you guys are smart. But stubborn. You’ve heard all your lives that the speed of sound changes as you increase altitude. And that isn’t wrong. But they weren’t telling you that it changes with altitude only because the temp is changing. JUST LOOK AT THE EQUATIONS TO CALCULATE SPEED OF SOUND THROUGH AIR!!!! For frick’s sake, just look at the equations. They all use only TEMPERATURE as the variable. In order to use altitude, you must first convert a given altitude into an average temperature at that altitude and then plug the temp into the equation and, voila, you have approximate speed of sound at that altitude.
So Jeremy, in the (rather) absolute vacuum of space, we can heat that up so there is sound travel comparable to sea-level-70F? Because that’s what your everybody-gets-a-gold-star education is saying.
For the sake of the shame you are imposing on your parents, please go back and repeat 5th grade science, then make it to HS without flunking.
You’re joking, right? This whole thing is ridiculous. I hope your example is in jest. Look, 1) you’d have a heck of a time trying to heat up your absolute vacuum and 2) it isn’t related to anything we’ve talked about. We are and have always been discussing the speed of sound in air. Period. In air. All of the equations you and I both posted are for solving the speed of sound in air. The variables that affect speed of sound in vacuums, water, steel, dead cats, etc, may or may not have any relevance. Might as well drag in the wookie defense and tell me that I’m incorrect about all of the above because I live in WA and have brown hair when everyone knows physicists have wild silver hair.
Doubt you want to go to this effort but…….
FWIW, if you recorded the two on a laptop and set the input level so that the impulse does not clip the input than you can determine what the relative SPL level difference is between the two and that is mainly what you’re after anyway.
When you get done you’ll most likely find out that “there was no discernible difference”.
One way to get your auto gain to play nice is to play a solid tone (say 440Hz or so) out the laptop speaker and use that to set your input level at a fairly low setting of maybe -40db or so. Then record a file where you shoot A/B/A/B for a few cycles. You need to then pull your waveforms into a freed editor with DB plotting on the amplitude. Record in PCM at 44K and 20-24bit if it has it.
When you get done after a few hours of messing around you’ll most likely determine that “there was no discernible difference”
Usually mics max out at like 85 db. Maybe 100 on the high end. Right? A suppressed pistol is typically around 124 db. On top of that, the impulse is so very fast that even microphones and db meters that are capable of measuring high enough miss the peak pressure of the shot because it’s too quick. It might record 110 for both ammos but the truth is that one spiked to 124 and one spiked to 126 and it just wouldn’t see it. Would your method get around any of this?
Usually mics max out at like 85 db. Maybe 100 on the high end. Right?
You don’t have to have the laptop next to the muzzle. You can have the laptop 10/20/50feet away to the point where the SPL does not exceed the limit. We’re not trying to determine the absolute amplitude but rather the difference between A & B. If the SPL is reduced by X db (lets say 30db) because you placed the laptop 50feet away it doesn’t matter. Both A & B will be diminished by the same amount.
A suppressed pistol is typically around 124 db.
If that is at the standard 1meter distance, then it’s 6db drop in every doubling of distance.
2M=118db, 4m=112db, …etc until the point you can record without clipping
On top of that, the impulse is so very fast that even microphones and db meters
Your not observing with a mechanical meter but rather being captured by an audio sampler running at 44KHz or better. The impulse is easily captured.
Finally if you had a regular SPL meter registering the absolute SPL of the tone being played you can in fact determine the absolute SPL of each A/B round by knowing the db value of the tone on the file, plus add the delta db of the spike of the gunshot + the SPL db adder due to the distance.
SPL versus distance calculator
http://sengpielaudio.com/calculator-distance.htm
“Your not observing with a mechanical meter but rather being captured by an audio sampler running at 44KHz or better.”
I had heard that even electronic/digital meters are incapable of measuring the peak impulse of a gunshot because of how short it is. But I’ll take your comments to mean that affordable meters simply do not sample at a high enough rate to catch it, and that I can get a laptop to do so. So… next question… how do I use my laptop to sample at 44KHz or faster? Is this as easy as downloading an audio sampling program? Are there any free ones? It IS something that interests me, and I understand that simply moving the mic away from the gun can get the volume level down to where it doesn’t max the mic out, but I was always under the impression that it still wouldn’t matter due to the peak SPL getting missed anyway (without using $$$$$$ equipment).
I had heard that even electronic/digital meters are incapable of measuring the peak impulse of a gunshot because of how short it is.
You are using the recording function of your laptop and any visual metering that may be displayed on your laptop display is meaningless. The important thing is that even the most basic laptop can usually record at 16bit/44,100 samples/sec. A gunshot is audible noise and the laptop will record faithfully the gunshot impulse and it’s amplitude. Make sure it is recorded in PCM or linear mode not some compressed MP3 quality format.
So… next question… how do I use my laptop to sample at 44KHz or faster?
Get to your sound card configuration by approximately via >control panel>sound>recording>internal mic>advanced>format (or therea abouts…your laptop will probably vary)
At that point you should be able to click on format and hopefully see a table of options and you generally want to pick the highest sample rate and highest bit rate)
Is this as easy as downloading an audio sampling program? Are there any free ones?
The built in sound recorder of windows can record at this high rate. You can also get some free (or near free) audio editors (check CNET) which have their own nicer recorders and waveform editors.
Your biggest problem in using a laptop is the gain setting and auto-gain-circuits of sound cards and laptops. They generally are a PITA but you can kinda defeat them by getting a solid tone playing out the laptop speakers and set your input gain so that the tone is causing a constant recording at say -40db or -50db or so. Check that first by just getting the tone going and adjust the speaker output and mic level input to -40db or so. Confirm you are at approx that level by recording a short file of just the tone and pulling that sound wave file into editor and confirm that you’re approx -40db down from max 0db fullscale.
Once you have that established place your laptop at a far enough distance away that the gunshot does not cause you to max out the input. You’ll have to check that but pulling that new file into the editor and confirming that its peak did not exceed 0db.
Lastly a laptop is a poor/cheap way to do this. A much better way is if you can splurge for a standalone digital recorder that isn’t going to have a crappy AGC on the input and you can use a standard calibrated microphone which makes getting absolute SPL readings much easier.
Something like this for $100 can probably be used to determine absolute DB levels right out of the box. With modest software, you can probably then also be able to tell what the harmonic content of the shot is comprised of that can further characterize why one shot may sound more irritating than another than maybe just SPL level.
http://www.amazon.com/TASCAM-DR-05-Digital-Portable-Recorder/dp/B004OA6JW0/ref=sr_1_2?ie=UTF8&qid=1392271047&sr=8-2&keywords=digital+audio+recorder
BTW don’t be turned off by the 125DB rating of that Tascam recorder. That 125db should be at a prescribed distance (check specs/manual). You’ll just need to put the meter at a known distance from the gun and factor in the loss due to the distance (i.e. if you set the meter 8m away you’d add 18db to the value of the recorder)
Consider some PMC e-Range ammo for silenced plinking. It’s the cleanest stuff I have ever shot. Even the brass is shiny inside.
I’m surprised Federal had the balls to release a “subsonic 45acp” product.
On the other hand, I was also surprised they released a true subsonic 9mm 124gr bullet.
Two products at the opposite ends of “are you serious?”
FWIW, my agency picked up one of these sound meters at radio shack.
We used it for all sorts of stuff. Traffic noise, parties, live bands… It’s really not bad for the price.
http://www.radioshack.com/product/index.jsp?productId=12680845
And yes, we used it at the range to make sure our night quals were at acceptable levels when the neighbors complained.
would love to see how it compares to the Bruel and Kjaer my forum uses for independent silencer testing.
http://nfatalk.org/forum/showthread.php?t=221
It may give a rough idea but there’s no way it’ll get the peak pressure. See my comment a couple posts up. Unfortunately, only units costing multiple thousands of dollars are apparently capable of actually catching the very brief peak pressure pulse. Additionally, suppressed firearms (even 9mm pistols) will often exceed the 130 db maximum of that unit, and often by a good amount. The first thing I wanted to do after buying a can was get a dB meter and start fooling around, but all of the research I did showed that the results would be essentially worthless unless I wanted to spend like $5,000+++ or rent something for a couple hundred bucks a day. And I don’t. haha
the radio shack meter is useless for measuring firearms. it doesn’t have anywhere near the response time to pick up a gunshot properly. if you use it to “legitimize” your quals, you are gonna get pwned in court. you’re going to wish you had spent the money on a proper meter.
Maybe through a carbine?
What horseshit. This is like selling bacon as a health food because it’s sugar-free. Of course it’s sugar-free: it’s bacon.
My favorite one is popcorn that says “whole grain” or “100% whole grain” on it. Duh. Yeah. Always has been and always will be. Are people buying one brand over another because one says “whole grain” and they think it’s healthier? uugghhhh
BTW — bacon has sugar ;-). Well, nearly all of the time. It’s cured and that’s typically done with sugar, brown sugar, maple syrup, honey, etc (along w/ other stuff like salts, of course).
I doubt that they think.
Healthy, sugar free bacon?! Shut up and take my money!
OFWG?
I am so into now calling anyone under 60 a SFYP
(Stupid F*cking Young Punk).
Intriguing. I’ve a friend with a suppressed 1911, and his weekend I’ll test the sound profiles for both types of ammo.
What I’ll use is a mouldy ouldie piezoelectric SONAR transducer cobbled to a diaphragm and a storage-type oscilloscope – my venerable Tektronix 7834.
I won’t get actual decibel numbers that way, but I’ll get a damned fine waveform, envelope shape and comparative intensity. I’ll then send a report to TTAG next week.
What is quietest non suppressed pistol and rifle? Is there much difference between a .22, 9mm, 45? Or 22, 223 or 308?
Looks like this marketing ploy has run it’s course. GunBroker bulk 45ACP ammo subsonic is now selling near the same as non_subsonic.
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