Muzzle blast from revolvers, what we know about it?

[Onty]

One of the factors I am looking for, when selecting loads for my revolvers, is listed pressure. When taking handgun while hunting, if in a hurry, the last things I have on my mind are earmuffs and/or plugs. In that respect, I prefer loads (for 44 Magnum now, and hopefully 45 Colt later) that are giving moderate muzzle blast, let say no more than from 30-06 rifle.

Seems to me that a general opinion is that less peak pressure (as listed in manuals) gives consequently less muzzle blast. In other words, starting loads for revolver at 18 to 23 kpsi should give less muzzle blast than maximum loads creating 36 to 38 kpsi.

Is that statement too general? What about smaller amount of fast burning powder that has a high listed pressure? Should we expect in some instances, due the higher expansion ratio in barrels like 6-6.5”, less muzzle blast than from loads with higher amount of slow burning powder, but less listed pressure?

When talking about "low" and "high" pressures that are results of starting and maximum loads, listed in some reloading manuals.

However, if I have it right, we are talking about the peak pressures in cylinders, and I am not sure about their effect on blast level on the muzzle. My point is that, due the expansion ratio in cylinder and barrel, smaller amount of fast burning powder, that has high starting pressure, might have lower muzzle pressure, and consequently lower muzzle blast, than load with larger amount of slow burning powder, with less starting pressure.

I searched internet and the best and simplest explanation I could find is this:

Internal Ballistics of Muzzleloaders https://www.celnav.de/muzzleloaders/internal_ballistics.htm

Generally, a fast-burning powder is more energy-efficient than a slow powder because it burns more completely during the residence time of the projectile in the barrel. This results in a lower residual gas pressure at the instant the projectile exits the muzzle. So, why should anyone want to use a slow powder at all? Because of the lower peak pressure! A heavy charge of fast-burning powder behind a heavy long projectile might develop a peak pressure exceeding the upper limit set by the gun manufacturer. Too high a peak pressure may further show itself by torn patches and reduced precision. While generally 3FG powder is a good choice for handguns and small- or medium-caliber (≤ .50) rifles firing round balls, the slower 2FG powder is better suited for rifles firing heavier long projectiles (except the smallest calibers). It is also better for big-bore (> .50) rifles firing heavy round balls (see below).



Although, this is about muzzleloaders and black powder, but the principle should be same for fast and slow burning smokeless powders.

I searched internet and there is nothing about muzzle pressure and muzzle blast for different loads. However, here are some data, but just for standard cartridges and firearms, assuming as per SAAMI specifications.

Gunfire Noise Level Reference Chart https://earinc.com/gunfire-noise-level-reference-chart/

In addition to the blast from the muzzle, when talking about revolvers, question is how much blast is generated due the gap between cylinder and aft side of barrel? I would say that should be quite difference in a blast from ordinary revolver with gap .006-.008”, from the gap like .002”, or even less, as on FA revolvers.

Talking about different powders and their loads, I checked on Hodgdon reloading website https://www.hodgdonreloading.com/reloading-data-center?rdc=true&type=53 , and found two interesting loads that could be compared:

Revolver: 44 Magnum, barrel 8.275”, bullet 325 GR. BTB LFN GC, starting loads:

Load 1: Powder IMR 4227, 17.0 grains, 1041 fps, 19 200 CUP

Load 2: Powder Winchester 231, 9.0 grains, 1035 fps, 32 100 CUP

The bottom line is; which load, using the same bullet, fired from the same revolver, with almost the same velocities, will give us less muzzle blast?

I hope that somebody knows more about this subject and could tell us from personal experience.

 

[Dave DeLaurant]

I haven't really studied this. I handload for so many different obsolete military cartridges that my efforts usually stop once reasonable functionality and accuracy have been achieved.

I do own a rather dated (1993) book on muzzle flash that approaches another aspect of this problem -- if you can find a copy, it may make interesting reading for you:

https://www.amazon.com/Handgun-Muzzle-Flash-Tests-Cartridges/dp/087364705X

 

[NeroM]

In addition to pressure; perhaps another factor to consider is velocity - super or sub sonic bullet velocity.
Supersonic adds a definite volume and sort of tone to muzzle report.
One 45 Colt load I make has a velocity of approx 1080 fps, this is subsonic to slightly below freezing.
The bullet is a SWC, which are not known to be the most accurate at trans sonic velocities - so this is accurate and sonically comfortable to shoot - above freezing. Last week when the outside temps were well below zero [speed of sound at zero is approx 1050 fps] - this load clearly had more report.
Another example is 22RF, hypersonic loads have more of a "crack" than traditional "target" loads.

 

[Barbaroja]

Interesting stuff, that said I’d definitely say try and make hearing protection more of a priority.

 

[J-Bar]

As I recall, OSHA requires hearing protection when employees are exposed to an average of 85 db for an 8 hour shift, or sound impulses greater than 130 db. Don't quote me on this, but I think these were the numbers when I was working in slaughterhouses. Your link to gunfire noise levels shows any hunting cartridge will exceed 130 db. If you are seeking a cartridge/load that produces a noise level less than 130 db without a suppressor, I don't expect you to be successful. Electronic ear muffs seem to be a reasonable solution if you want to listen to environmental sounds between shots.

Without doing research or experimentation, it seems logical that more pressure should produce more blast. A thought experiment: take two identical inflated balloons. Let the air escape from one slowly and it is nearly silent. Stick a pin in the second balloon and it deflates with more noise because the rapid release of pressure creates a shock wave. I expect that releasing more pressure quickly, as in firing a gun, would create a bigger shock wave, more noise.

Good luck on your search.

 

[Onty]

I haven't really studied this. I handload for so many different obsolete military cartridges that my efforts usually stop once reasonable functionality and accuracy have been achieved.

I do own a rather dated (1993) book on muzzle flash that approaches another aspect of this problem -- if you can find a copy, it may make interesting reading for you:

https://www.amazon.com/Handgun-Muzzle-Flash-Tests-Cartridges/dp/087364705X

Thanks for the tip! Looks like a good book about muzzle flash issue. I wish if there is something similar about muzzle blast from revolvers.

I found something about this subject in thread Quiet .357 Magnum Loads? https://thefiringline.com/forums/showthread.php?t=499590 , post #22. Apparently, QuickLOAD could predict muzzle pressure, and that could be a good indication of the muzzle blast level. If somebody has QuickLOAD, please check is this statement regarding muzzle pressure applicable for revolvers. Also, in the same post author stated "For example, Power Pistol is known for muzzle blast, while some of the VitaVuori powders are noted for lack of it."

Another good info I found some years ago is that, when bullet exits barrel faster than speed of sound, the crack created also contributes to a louder report. However, that's not all. If revolver bullet is lunched at bit faster speed than speed of sound and subsequently slows down in subsonic range, revolver bullets is prone to instability, resulting in somewhat poorer accuracy further on. The only bullet shape that is not affected by this is truncated cone (TC) nose, see post #14, written by James Gates ("Dixie Slug") https://castboolits.gunloads.com/showthread.php?48098-Gates-Extreme-Meplat-Bullets .

Regarding bullet velocity at 1100 fps, in this thread https://www.levergunscommunity.org/viewtopic.php?t=19554 , posted Tue Jul 28, 2009 12:31 pm, Terry Murbach wrote:

...I DO KNOW I CAN RUN 300gr BULLETS AT 1100FPS FROM ALL MY 45COLT SIXGUNS INCLUDING THE COLT AND S&W M25-5 GUNS OF VARIOUS BARREL LENGTHS WITH LOADS THAT ARE STRAIGHT OUT OF THE LAST FEW SPEER MANUALS.
A 45 CALIBER 300gr LFN BULLET AT 1100 WILL COMPLETELY PENETRATE ANY ANIMAL IN NORTH AMERICA AND YOU NEED NOTHING ELSE. MORE SPEED MAY FLATTEN THE TRAJECTORY A BIT-- darned LITTLE TOO AS A MATTER OF FACT-- BUT ALL YOU ARE DOING AT 1100 OR 1300 IS POKING A 45 CALIBER HOLE IN AND A 45 CALIBER HOLE OUT.
THE MOST INTERESTING PART OF THIS TO ME IS THE FACT THAT A 454424 KEITH BULLET AT THE SAME SPEEDS--1050 TO 1100-- DOES THE SAME WORK AND DOES IT AT EVEN LOWER PRESSURES.

At the first moment I was puzzled why Terry Murbach is mentioning 1100 fps, just tad less than speed of sound. Looks like he prefers that velocity for 300 grain bullet, as well as for 260 grain one. Well, seems to me that he wanted to avoid a sonic boom and louder muzzle report when bullet exist barrel faster than speed of sound, and also, instability (and accuracy) issue when bullet is going from super-sonic to sub-sonic velocity.

 

[ahutch71]

All I can tell you is that with near max loads of Blue Dot, this happens.

 

[ahutch71]

Have been sitting here thinking about this, and here’s my non-scientific (aka experience based) ruminations.

I’d categorize the muzzle report sounds into 5 categories:
1. Whump - this is what you get from .50 cal Muzzleloaders with moderate loads of BP or Triple 7. 80-100 grains. Also what I experience with my 45 Colt Trail Boss loads.
2. Crack - the sound a 22 makes. Standard loads (sub-sonic) and a light crack, supersonic are a louder crack.
3. Bang - most 38 specials make a light bang. 115 grain 9mm make a louder bang, since they’re adding a supersonic element. “Bang” has a wide spectrum, but it’s definitely not a Whump and it’s much longer and louder than a Crack.
4. Roar - this is what you get from your 357, 41 mag, 44 mag. Loud and long.
5. Short barreled AK - a class unto itself, this is a sound that clears out the rifle benches and creates enemies and generates dirty looks.

All that said and in line with your quest for a less deafening hunting load from your 44, I’d recommend looking at running 44 Specials w/ heavy loads of Unique. I’m a huge fan of the Skeeter Skelton load, which is a Lyman 429421 (245 grains) and 7.5grains of Unique. It’s safe in 44 Mags and stout (Ruger Blackhawks, etc) 44 Specials. Mine chrono at about 1050 fps, are not obnoxiously loud, and work like a charm for hunting purposes from either revolver or carbine (although test for feeding reliability in your levergun…they work in my Marlin 1894 but give my brother in law’s Henry fits). Anyhow, 245 grains at ~1,000 fps with a relatively hard cast projectile will work on just about everything, and one or two won’t leave you learning sign language in your spare time.

It’d be interesting to get a decibel meter and test the difference between sound levels for two rounds at the same velocity, but one loaded with a slower powder and one with a faster powder. I would think that the lower pressure load would be quieter but perhaps with more late burning powder generating more flash, but that’s just speculation.

Now I need to come up with some good excuses to explain to my wife why I ordered a decibel meter from Amazon. <<sigh>>

 

[westernrover]

Insomuch as muzzle pressure is a determining factor of sound pressure level, the faster-burning, more degressive powder is going to produce a lower sound pressure level.

Research has correlated barrel-length and muzzle pressure with increased sound pressure level. For example, one project used pressure transducers and measured the muzzle pressure of an AR-15 barrel that was reduced in length incrementally by an inch. The shorter the barrel, the higher the muzzle pressure, the higher the SPL. The difference in muzzle pressure resulting from fast/degressive powders versus slow/progressive powders is less than that of barrel length, especially substantial barrel lengths in rifles (ie. 9" vs 24").

We also understand that the reason a suppressor works is because it reduces the pressure differential between the space behind the bullet exiting the muzzle of the suppressor and the surrounding atmosphere. The pressure at the muzzle of the gun bore has been allowed to expand into the baffle chambers of the suppressor thereby reducing this pressure differential. One novel design for a no-baffle suppressor or more accurately, an integrally-suppressed barrel consists of a barrel that vents progressively into a concentric tube: [SHOT 2023] New No Baffle Vanquish Suppressors from Angstadt ArmsThe Firearm Blog Again, the progressive pressure-relief allows the bullet to exit into the atmosphere at a low pressure differential resulting in a lower SPL.

I use QuickLoad to model muzzle pressure for my loads. Unfortunately, I don't have a SPL meter that can accurately measure transients as quick as a gunshot. I have several pro-audio SPL meters and phone/tablet apps but they're not accurate for gunshots. Theoretically, a load that uses Titegroup or Clays to achieve a certain velocity with a particular bullet will have a lower SPL because it will certainly have a lower muzzle pressure than another load that achieves the same velocity with Blue Dot, 2400, or Power Pistol which will produce a higher muzzle pressure, even though the MAP will be lower.

Because of this, 357 and 44 Magnum can be loaded to be quieter than 38 Special and 44 Special loads that produce the same velocities. The Magnums can be loaded with faster powders resulting in greater "thrust" but over a shorter period of time. As your pressure/time curves show, the muzzle pressure will be lower. The Specials cannot be permitted to exceed a lower MAP, so they must use a lower level of "thrust" over a longer period of time to achieve the same muzzle velocity. Because of this, the muzzle pressure and resulting SPL will be higher.

This is why I greatly prefer high-pressure Magnums and I am willing to load to ~40,000 psi or more (or CIP maximum) and look forward to advances in materials technology that will enable still higher chamber pressures. I believe the result is less muzzle blast.

 

[V-fib]

made the mistake of shooting my ported Taurus .357 without popping my muffs on. Not fun. should have been wearing my Sonic II ear plugs. perfect for still hunting with a revolver as you can clearly hear low decibel sounds but when firing your hearing is protected. If hunting from my condo with my 30.06 I use full plugs.
the sonic II's are no longer made but a substitute is available that works just as well.

see the link for a example

https://www.earplugstore.com/health-enterprises-acu-life-shooters-impact-ear-plugs.html

 

[__steve__]

Interesting topic, but maybe there’s too many variables at hand to effectively work a desirable load. The end result would be opting for, say 6% permanent hearing loss over 8%.

Not related much but I can’t forget when I forgot to wear earmuffs, only had the foamy plugs in, chronographing 500 mag loads through the compensated 4”. The shockwave sent through my brain was not pleasant at all.

Does anyone have a good noise canceling product for recommendation?

 

[ahutch71]

Interesting topic, but maybe there’s too many variables at hand to effectively work a desirable load. The end result would be opting for, say 6% permanent hearing loss over 8%.

Not related much but I can’t forget when I forgot to wear earmuffs, only had the foamy plugs in, chronographing 500 mag loads through the compensated 4”. The shockwave sent through my brain was not pleasant at all.

Does anyone have a good noise canceling product for recommendation?

I really like my Peltor noise canceling earmuffs. They’re great for all handguns. When I get into very loud stuff (I consider ARs and AK/7.62x39 with 16” barrels, 308, 30-06, 7mag, etc in this category) I’ll double up, and use foam earplugs and the Peltors over top of them.

 

[westernrover]

It should be understood that most electronic hearing protection is not active noise canceling, but passive attenutation with electronic pass-through with a limiter. Noise canceling is most widely used on microphones to limit transmission of background noise. Active noise canceling is sometimes used for hearing protection in some headsets, typically used for rotorary-winged aviation, but it also works great for wind noise and other more predictable sounds.

Does anyone know of an active noise canceling headset intended for gunfire?

 

[PWC]

Besides muzzle blast, there is side blast from the cylinder gap.

Never let someone stand forward of your shoulder when using a revolver.
As a NRA Junior coach, I used to use a piece of legal size printer paper draped over the revolver with the ends pulled tight and held together below the trigger guard.

When the gun is fired, the paper is blown apart with powder marks and maybe shaved lead.

Graphic illustration of why don't stand next to a revolver when fired.

Edit: the above applies to 38 Spl and above, 22 may not blow paper apart but will show debris.

 

[Palladan44]

A .38 Special can be worse to shoot (to the unprotected ears of the shooter) or any handgun for that matter, than a .30-06 rifle, without hearing protection.
It has to do with how much closer your ears are to the muzzle, and how sound waves travel. This is just how it is with handguns unfortunately.

It's not about how loud the gun is in and of itself, because obviously a .30-06 is louder than most any handgun, but it just has to do with the location of the muzzle relative to your eardrums. It's not about the decibel level of the firearm at the muzzle, that value means next to nothing in this case of "heard" muzzle blast to the shooter (reminds me of the term "felt" recoil)
You can hear a .30-06 Report from many miles away 6 or 7 miles, where a .357 Magnum snubby, only about 4 miles away....
But you can be deaf in as little as.......one shot with that 357 where you can get away shooting a .30-06 with a little ear ringing for 10 minutes and then good to go.

There's no possible way to get around this im afraid.

A Heavier bullet traveling slower is your best bet probably, the pressure wave created by the sonic boom of the bullet will contain less pressure, aka. will compress the air to a lesser psi. than a faster bullet. This particular phenomenon has nothing to do with the p.s.i. of the combustion behind the bullet.....
Anyways, you can kill Deer with a light loaded 44 Mag with pretty darn good success. Don't be afraid of a 270 grain LSWC going about 950 fps. It will be sub-sonic and still kill deer. You might have to track them a little ways, similar to an Archery shot....the full house magnums with say a 240 XTP loaded with WIN-296 I'm not expecting to track the deer far, if at all...but ears might be ringing for a day or.....a week.

 

[243winxb]

"Flash suppressants interrupt free-radical chain reaction in muzzle gases and work against secondary flash. They are typically alkali or alkaline earth salts that either are contained in the formulation of the propellant or exist as separate granules."

Look at powder sds, to see what powders has them.https://hodgdon.com/resources/safety-data-sheets/ calcium carbonate is used as a flash suppressant. Ball powders.

The faster burn rate powders will have less unburnt powder exiting the muzzle. Less muzzle flash.

Secondary flash needs the correct fuel, air mix to flash.

https://apps.dtic.mil/sti/citations/ADA126129

 

[doubleh]

One of the factors I am looking for, when selecting loads for my revolvers, is listed pressure. When taking handgun while hunting, if in a hurry, the last things I have on my mind are earmuffs and/or plugs. In that respect, I prefer loads (for 44 Magnum now, and hopefully 45 Colt later) that are giving moderate muzzle blast, let say no more than from 30-06 rifle.

I used to hunt that way. Now I am half deaf as confirmed by tests. The thing is that today we have comfortable hearing protection that allows you hear even better than normal if you are a deaf old fart and also as good or better if you have no problem at all. There is no need at all to hunt without hearing protection today. Plan ahead.

 

[hso]

the last things I have on my mind are earmuffs and/or plugs. In that respect, I prefer loads (for 44 Magnum now, and hopefully 45 Colt later) that are giving moderate muzzle blast

There may be a correlation, but I'm not aware of it. You'd have to assume that dB are above 140 and therefore capable of permanently damaging hearing to some small extent until you have real data on sound pressure levels to assure you that the risk is minimal for incremental hearing loss.

 

[Riomouse911]

Revolvers have a triple threat to your ears; cartridge pressure, powder burn rate and the B/C gap.

The .357 Magnum revolver packs an audio wallop with a high decibel report when loaded to standard magnum pressures, like this 140 JHP over a dose of H-110 from a 4” 686+;



Even lighter magnum loads, like a 158 gr coated SWC over Unique from a 66-1 4” with a .002 larger gap;



Moderate loads are more pleasant to the shooter than full house, but still damaging to the ears. Same 66-1, mid-range load;



The .22 WMR runs at a moderate pressure compared to magnum revolvers, but I guess the slower burning powder makes the flash and bang just about as bad as a .357. Model 48 4” with a .004 B/C gap;



Of course nothing I can whip up out of my handguns tops the report of a 14.5” AR with a 2-port Surefire suppressor mount being fired without the can;



All gunfire is bad for ears, cover up!

Stay safe.

 

[JeffG]

Most of my experience with handgun muzzle blast is hands-on, subjective. The more boom, the more blast, I like mid range SWC out of my 44s and 45s for that reason.

Full power out of my Ruger Vaquero, 44mag, 3 3/4 inch barrel.

https://www.youtube.com/shorts/AEhXGSv3sTU

 

[Leon tP]

...

Talking about different powders and their loads, I checked on Hodgdon reloading website https://www.hodgdonreloading.com/reloading-data-center?rdc=true&type=53 , and found two interesting loads that could be compared:

Revolver: 44 Magnum, barrel 8.275”, bullet 325 GR. BTB LFN GC, starting loads:

Load 1: Powder IMR 4227, 17.0 grains, 1041 fps, 19 200 CUP

Load 2: Powder Winchester 231, 9.0 grains, 1035 fps, 32 100 CUP

The bottom line is; which load, using the same bullet, fired from the same revolver, with almost the same velocities, will give us less muzzle blast?

I hope that somebody knows more about this subject and could tell us from personal experience.

If it were me, I would expect more muzzle blast from the IMR 4227 load. It's a heavier charge of a slower burning powder. It's No. 89 on the latest burn rate chart I can find, it compares with Winchester 296 at (#88) and Hodgdon H-110 at (#87). Further on down the line is Accurate #9 at (#79) and Hodgdon Longshot at (#74).

Compare that to Winchester 231 which sits at (#40) on the chart. It compares to Hodgdon HP-38 (#39) or Alliant Unique at (#45) and Hodgdon Universal at (#47).
https://loaddata.com/Article/BurnRateCharts/Powder-Burn-Rate-Chart-NEW/159

Finally, I can't just ignore the fact that 17 grains of any powder is going to create more gas volume than 9 grains, so I would expect greater muzzle pressure from the IMR load.

"In addition to the blast from the muzzle, when talking about revolvers, question is how much blast is generated due the gap between cylinder and aft side of barrel? I would say that should be quite difference in a blast from ordinary revolver with gap .006-.008”, from the gap like .002”, or even less, as on FA revolvers."

As for that cylinder gap...

Just look at Riomouse's post


No matter what load you decide on, you should really consider hearing protection.

 

[Onty]

Thanks to all for good advice. When on the range, safety glasses and ear protection are the must, I never miss that practice. Just to make it clear, I don't hunt using revolver, just rifle, local law. However, I carry handgun for coup de grace and as last ditch defense when facing wild boar. These are true wild boars, not feral pigs (never had those), and is not uncommon to find some as large as 250 kg (550 lb). They are very nasty and aggressive when wounded and/or cornered.

Yeah, I am aware of loud bang from full power 357 Magnum. Because of that, I would rather have milder loaded 44 Magnum or 45 Colt. Effect will be at least the same or better, then using top load of 357 Magnum, with considerably less muzzle blast. I am just searching for something like 250-270 grains at 1100 fps, and muzzle blast as low as possible.

 

[NeroM]

Yeah, I am aware of loud bang from full power 357 Magnum. Because of that, I would rather have milder loaded 44 Magnum or 45 Colt. Effect will be at least the same or better, then using top load of 357 Magnum, with considerably less muzzle blast. I am just searching for something like 250-270 grains at 1100 fps, and muzzle blast as low as possible.

For 41, with 250 gr around 1100 - consider the CPC 250 gr bullet with something around 14 gr 2400 - reasonable blast.
I am a big fan of 41, however have to admit shooting 45 Colt more and more lately with 255 gr bullet at approx 1000 fps,
for me 9.5 gr Hero [top of Tier 1] to 10 gr Hero [into Tier 2] range. 9.5 gr is "quiet" compared to 357 or even reduced 41.
The 255 gr SWC/9.5 Herco has been very effective on deer size game.

 

[P Flados]

I have run lots of loads in Quickload while looking at muzzle pressure. It also shows another parameter (propellant burn %) that probably has a big impact on perceived muzzle blast. The combination of high muzzle pressure along with powder continuing to burn after the bullet leaves the muzzle is a double whammy.

When helping people trying to select a round to get a very low report from a long gun, I have found that one parameter that reduces muzzle pressure is reducing the air space in the round.

 

[JTHunter]

Onty - considering the gap between the cylinder and the forcing cone, some burning powder and gas leaks out there. Using the faster powder gives the bullet a better start.