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action noise and suppressor hosts

Posted: Fri Aug 31, 2018 9:09 am
by John A.
Good morning guys.

I was writing to get a discussion started.

We all know there are suppressors out there being made right now in certain calibers that are among the quietest that have ever been developed.

It's not terribly uncommon to read about or watch a video where a rimfire can is down into the mid one teens. I've seen a few meters show all the way down to ~114db.

Then turn around and watch another video where someone will check to see how loud their 10/22 bolt is when it's slamming shut and see where it's about 115db.

So, my question is, why aren't there more striker fired suppressor actions out there?

I mean, yeah, I know suppressors address the biggest part of the equation, but there are so many other variables than just the suppressor.

When I was working on my 300 blackout, I was seriously disappointed in how loud it was suppressed (with factory ammo). I was seriously let down by it. I've always said that it was more akin to someone banging garbage can lids together than it was a good sound with a can

So, I started loading my own and experimented with other powders and things until I got the sound down into what I feel was a more acceptable sound.

We all know that suppression isn't just about the can.

So, why aren't more industries looking into making their hosts more quiet?

I know there's a market for it. It's not just about the civilian market either. There's a lot of militaries that their special units would be very interested in having a host that is sincerely more quiet.

And it would seem to me that striker fired bolts and trigger systems would be more common and prevalent.

I can take my Ruger 10/22 (hammer) and dry fire it right beside of my Savage FVSR and the FVSR is hands down and noticeable more quiet between the two.

If one could make a striker fired conversion for most of the popular choices out there (like pistol caliber AR's for instance) I have no doubt they'd sell like hotcakes.

I think most of us would agree here that suppression isn't just about the muffler. If one were to design a truly unique suppressor and host, you'd have to look at the whole picture. Not just a portion of it.

Re: action noise and suppressor hosts

Posted: Fri Aug 31, 2018 11:56 am
by Capt. Link.
We could discuss how one would design a quiet host or modify what is available.

I suggest that polygonal rifling should be a standard for any suppressed weapon. The superior seal and long lived accuracy would give the host a good base.
-CL

Re: action noise and suppressor hosts

Posted: Fri Aug 31, 2018 12:07 pm
by John A.
Thanks for the reply Capt. Link.

If one is going to design the most quiet suppressor host out there, no part of the design should be taken off of the table. Rifling too.

Re: action noise and suppressor hosts

Posted: Fri Aug 31, 2018 12:59 pm
by fishman
Why does it matter if the host is striker or hammer fired? The muzzle blast is always going to be louder than the hammer falling

Re: action noise and suppressor hosts

Posted: Fri Aug 31, 2018 1:37 pm
by Stan1
Agreed on strikers being quiet and 10/22s being really noisy.

I've metered my Welrod on an empty case at 89.7 (87.3-90.5), and my 10/22 bolt drop feeding a CCI Std Vel at 116.8 (114.0-120.3). Compare the bolt drop to a 19" pump action .22 firing CCI Std Vel with a Regulator at 118.0 (116.0-119.0).

So yeah, bolt or falling block striker fired get my vote.

Re: action noise and suppressor hosts

Posted: Fri Aug 31, 2018 2:49 pm
by John A.
fishman wrote:Why does it matter if the host is striker or hammer fired? The muzzle blast is always going to be louder than the hammer falling
Because a suppressor is only one piece of the puzzle.

There are a lot of different types of guns. Some suppress better than others. And as I'm sure we both agree, some hosts are louder than others. There are reasons why.

If you are going to design a suppressed gun from the ground up to be the epitome of quiet suppressed guns, should you not use the best aspects of things that you know are better?

Or at least, that's how I see it.

So, I wanted to just have a discussion of things that we know work better. Maybe someone will pay attention and actually design a good suppressor host rather than just thread a can on the end of whatever gun it will fit on. Anyone can do that. But this topic was meant to come up with things that are ideal to use in a good host.

Re: action noise and suppressor hosts

Posted: Fri Aug 31, 2018 7:13 pm
by Stan1
I'll change my vote from bolt or falling block to a more generic locked breech and manual action of some type.

Long barrels vs. short.

And wipes. Wipes and ablatives are good :mrgreen:

Enough wipes change the sound from a muffled bang or phew to "click". People who are very experienced with all types of firearms are surprised by how a click sound doesn't sound like a firearm. Another option for this thought experiment.

Suppressor design may be out of scope of this thread but if you're looking the total package...

Re: action noise and suppressor hosts

Posted: Fri Aug 31, 2018 9:10 pm
by cdhknives
fishman wrote:Why does it matter if the host is striker or hammer fired? The muzzle blast is always going to be louder than the hammer falling
The point earlier in this thread is that some very good suppressors with good subsonic ammo are reducing the muzzle blast to below levels caused by the action cycling...so the action cycling in some (and increasing as technology improves) systems is the limiting factor in noise level.

The hammer impacting the firing pin is a source of noise the striker fired actions do not have. Most of my bolt actions are quieter than my (gas system inactivated) AR's for example...testing with a fired shell in the chamber so all I get is hammer fall noise.

Re: action noise and suppressor hosts

Posted: Fri Aug 31, 2018 9:52 pm
by ECCO Machine
Stan1 wrote: And wipes. Wipes and ablatives are good :mrgreen:

Enough wipes change the sound from a muffled bang or phew to "click". People who are very experienced with all types of firearms are surprised by how a click sound doesn't sound like a firearm. Another option for this thought experiment.
Yeah, but who wants to mess with wipes and gel mess for range blasting? Even assuming they don't negatively affect accuracy, it's not a chore I'd want be dealing with every other magazine.

I don't much care about action noise, as it's not offensive to my ears. Port noise can be, and as you guys know, I've developed and continue to work on designs to mitigate that (without giving up muzzle noise reduction like OSS), but port noise can easily exceed hearing safe on some guns, so that deserves attention. 115, 118 dB of action noise may not satisfy a Hollywood quiet expectation, but if one of us comes up with a centerfire can that drops 9mm or .45 down into the one hundred teens, we'll be beating back customers with long sticks. I don't think I'm there yet, and I'm still waiting on my new B&K mic to get hard figures with my meter, but have a look (or listen, as it were):

Listen to the trigger reset, which I paused for between shot #10 & 11

https://www.youtube.com/watch?v=H3-xoF1 ... 1rk0h00410

Re: action noise and suppressor hosts

Posted: Fri Aug 31, 2018 11:06 pm
by fishman
If you are going to design a suppressed gun from the ground up to be the epitome of quiet suppressed guns, should you not use the best aspects of things that you know are better?
99+% of people don't want a gun designed to be the epitome of quiet. They want a highly useful gun that is quiet enough. When you make all your design choices based on absolute maximum suppression, you lose so many other things in the trade offs of those decisions. It would be a neat project, but its never going to be mainstream. Getting caught up on hammer vs striker seems ridiculous to me unless you're shooting an integral bolt action 22 and you can actually noticeably hear the hammer drop without specifically listening for it.

Re: action noise and suppressor hosts

Posted: Sat Sep 01, 2018 4:10 am
by yondering
fishman and ECCO, if you're not interested in a discussion on reducing action noise, why are you participating in the thread? Don't assume your own preferences apply to everybody else, or even "most people". There's no value in bringing those comments into the discussion; pursuing mediocrity or thinking of reasons not to improve things is not what some of us here are interested in, and not what we're trying to discuss here.

Back to the discussion - I absolutely see the benefit in pursuing quieter actions for suppressed use. Of course that's why some of us use bolt actions and single shots for the truly quiet guns, but others like the 10/22 have always been a pretty loud action. I noticed that years ago, comparing suppressed 10/22 rifles against the Marlin 60/70 series actions; the Marlins were always significantly quieter but also were harder to tune for subsonic rounds. (I did get one working right for strictly subsonics and still have it, it's a much quieter suppressor host than any 10/22 I've heard.) Part of that is the dull thud of the Marlin bolt closing, but also the hammer strike is pretty quiet compared to the 10/22.

The Browning Buckmark is another example, the action is fairly loud compared to the Ruger Mk 1-4 series guns. Some of that is port noise, where the fully open action of the Buckmark lets out a lot more sound than the enclosed Ruger action. Another part of that noise is the bolt ringing though, while the Ruger in comparison has a very flat/dead sound that's favorable to suppressed application.

Re: action noise and suppressor hosts

Posted: Sat Sep 01, 2018 7:16 am
by fishman
fishman and ECCO, if you're not interested in a discussion on reducing action noise, why are you participating in the thread?
So, my question is, why aren't there more striker fired suppressor actions out there?
I was answering the questions posed in the OP.

Re: action noise and suppressor hosts

Posted: Sat Sep 01, 2018 7:47 am
by John A.
I have never been one to just "settle" for anything when I know something can be better. This conversation is for ideas to make it better.

And I do think the market wants the "most quiet". Why else would people spend 3 weeks looking at db numbers of the various manufacturers cans. When you spend that much money wanting the most quiet can out there, the same should be said for putting it on the most quiet gun out there.

Bolt ring can be changed by using a different metal (or material) where the two parts contact each other.

Aluminum for example has a "deader" tone. If you drop a piece of aluminum rod for instance, it'll make more of a thud than if you were to drop a similar piece of steel, which will ting.

I'm not suggesting to make an aluminum bolt, but you could theoretically notch the steel bolt to accept an aluminum (and replacable if necessary) bolt face.

There are many different types of nylons and plastics that would probably work even better than aluminum. And with better sound and vibration absorbing characteristics.

Or, if you didn't want to make a bolt insert, you could make one around the face of the barrel to deaden the sound when the bolt closes up against it.

Ejection port noise is something else that will need to be addressed for gas operated semi or FA's. It would be possible to quieten it down some too. But the most quiet are going to be the various single shot actions. Even by using one of the hard plastic shell catchers seem to reduce action noise in semi's. Granted then you have to deal with the empty cases rolling and rattling around making their own noise.

Taking it a step further based on that observation, it would be possible to make a rainbow arc cover that would go over the ejection port that would direct the empty cases (and the escaping gasses) downward without capturing them.

The ejection port cover would stick out more from the side than other traditional designs which may not bode well for left handed shooters, but it wouldn't necessarily have to be huge. Just large enough to redirect the empties and the sound downward to the shooters feet where the earth is going to mitigate the sound rather than just out to the atmosphere.

I would actually prefer not to have the ejection port cover too long so you could still reach up in there with your finger if you did have a malfunction and shake or dig out the brass if you had to. But the longer port would cover all of the ejection port flash that would be visible from others and redirect the noise downward toward the ground rather than just "out everywhere". While not really a consideration for casual shooters, that idea alone would make our service members safer because they would be less visible to people that want to shoot back at them.

On most subsonic loads the ejection port gasses would cause minimum disturbance to the surrounding area (leaves, snow, etc.). After all, you're not going to be able to stop that because of how the gun works, but the gas can be changed in how it's allowed to escape in a way that would make the host more quiet. And less visible to anyone that is around them too. Especially at night or low light.

The puff of smoke would also still be present either way. I don't really know of a way to reduce that other than faster or cleaner burning powders. But redirecting the ejection port noise could still be beneficial in reducing the sound the host is going to make. It's going to be there regardless, the question is what can be done to mitigate or reduce it?

The reason that bolt actions, Single shots, even lever actions are the most quiet hosts at this time is the closed actions don't rely on the gas to work the actions and is why when people want "quiet" right now, that's what they go to. And why the venerable Delisle is one of the most quiet suppressed guns that has ever been in service for that reason.

On a slight sidetrack, one of my most quiet hosts is a break action single shot NEF Pardner. When shooting mild 38's through it, it is very quiet. And there is very little hammer noise at all. It has that "thud like" sound you mentioned.

Image

Re: action noise and suppressor hosts

Posted: Sat Sep 01, 2018 8:23 am
by John A.
Stan1 wrote: Long barrels vs. short....
That's also a good point Stan.

Where sound suppression is concerned, shorter isn't always better.

Sure, you get less velocity with a shorter barrel (usually), but you'll often have more unburned powder entering into the suppressor making more FRP and make it harder for the suppressor baffles to do its' job. And a louder shot.

Whenever possible, contrary to popular belief, longer barrels are often more quiet because the gasses have already burned out and are already in the process of cooling before it even reaches the suppressor. Provided that you can keep the velocity of the bullet down below supersonic speeds out of the barrel. You could only determine that with testing different lengths and how they perform. Then choose the one with the most velocity (below super) and the most quiet db rating. Somewhere along the way, you'll find the best choice that balances both.

Barrel length choice would depend a lot on the burn rate of the powder you're shooting, but I will add by saying barrel length should be a consideration depending on the caliber and the best powder you can use in it.

I often use Enforcer powder in my most quiet sbr'd blackout handloads. It burns out in about 6 inches of barrel. The pressure peaks quickly and chamber pressures are actually upwards of what a standard 223 is, but it burns out quickly and the result is several db reduction compared to other, more common, powders that people are using. I also have observed less ejection port noise and gassing of the shooter. Probably due to the powder burn rate too.

Re: action noise and suppressor hosts

Posted: Sat Sep 01, 2018 12:50 pm
by ECCO Machine
yondering wrote:fishman and ECCO, if you're not interested in a discussion on reducing action noise, why are you participating in the thread? Don't assume your own preferences apply to everybody else, or even "most people". There's no value in bringing those comments into the discussion; pursuing mediocrity or thinking of reasons not to improve things is not what some of us here are interested in, and not what we're trying to discuss here.
Because the question wasn't what can be done to make them quieter. It was " why aren't there more striker fired suppressor actions out there?.......... why aren't more industries looking into making their hosts more quiet?"

The answer is because 1) the market segment of those shooting suppressed vs. unsuppressed, while growing, is still tiny and 2) the empirical evidence suggests that relatively few people in the small subset of suppressed shooters are especially concerned with it.

I also feel this is spot on:
fishman wrote:When you make all your design choices based on absolute maximum suppression, you lose so many other things in the trade offs of those decisions.
And you actually reinforced his point:
yondering wrote: I noticed that years ago, comparing suppressed 10/22 rifles against the Marlin 60/70 series actions; the Marlins were always significantly quieter but also were harder to tune for subsonic rounds. (I did get one working right for strictly subsonics and still have it, it's a much quieter suppressor host than any 10/22 I've heard.)
As well, outside of the quietest .22 rimfire cans, the report from the muzzle is still considerably louder than the action. Port noise is an issue to be addressed, one which I've made a personal mission. With centerfires, though, until we get cans which reduce muzzle report to levels lower than action noise and keep back pressure down to where port noise is also below that level, I see relatively little use in making the actions quieter. Be kinda like worrying about the abrasion on your knee while there's an arterial bleed at the ankle.

I'm happy to participate in a technical discussion about what can be done, and I think it's certainly worth of consideration. But that wasn't the question asked here.

Re: action noise and suppressor hosts

Posted: Sat Sep 01, 2018 1:03 pm
by John A.
ECCO Machine wrote: I'm happy to participate in a technical discussion about what can be done, and I think it's certainly worth of consideration. But that wasn't the question asked here.
I thought it was obvious enough to be implied.

Re: action noise and suppressor hosts

Posted: Sat Sep 01, 2018 7:33 pm
by yondering
John A. wrote:
ECCO Machine wrote: I'm happy to participate in a technical discussion about what can be done, and I think it's certainly worth of consideration. But that wasn't the question asked here.
I thought it was obvious enough to be implied.
I thought it was pretty obvious too, since that discussion was already happening.


On longer barrels - absolutely! My quietest suppressor host is a 24" barreled 22 bolt gun; the difference between that and the kid's 16" bolt gun is pretty significant. That rule applies to every caliber I've tested it on, with the exception of using a barrel short enough that "standard" ammo remains subsonic. Even that is just elimination of crack though, the muzzle blast itself is still quieter on the longer barrels.

John, I've been looking for one of those Handi-rifles in 38/357 like yours for the same reason (and so the 10 year old can hunt with it). Sell me yours? :D J/K but if you know a source for them, even as parts to assemble from another caliber, I'm all ears.

Re: action noise and suppressor hosts

Posted: Sun Sep 02, 2018 7:05 pm
by doubloon
I in the boat with believing it was implied and happening as well.

I've seen videos where people highlight the action noise but I don't recall seeing any tests specifically focusing on action noise.

Has anyone ever metered something like hand manipulation of a 10/22 bolt? Rack it back hard and let it go without a trigger pull?

Re: action noise and suppressor hosts

Posted: Sun Sep 02, 2018 7:18 pm
by a_canadian
Seems a fairly simple test to set up. A plywood sheet with a hole in the middle, rubber or heavy wool felt dam, poke the muzzle through and thread on a can. No way the suppressed shot on the other side of the plywood is going to meter as high as the action noise that way.

Re: action noise and suppressor hosts

Posted: Sun Sep 02, 2018 7:57 pm
by John A.
That's a good idea of using a piece of plywood or paneling or something to just read the action noise. That makes a lot of sense actually.

Place the meter 3 foot away and there you go.

I've been thinking of getting one of those cheap db meters. I don't pretend that it would be as accurate as one costing hundreds or thousands of dollars, but should be able to tell if one is more quiet than another.

Re: action noise and suppressor hosts

Posted: Sun Sep 02, 2018 8:22 pm
by a_canadian
If you get the most common form of SPL meter, you may want to dial the calibration all the way up. I found mine to offer more consistent results with the rheostat cranked all the way to max, pushing the numbers up. Still a fair but below actual dB numbers for suppressed gunshot level impulses but a bit more consistent from shot to shot, and comparing one system to another. I guess it's slightly logarithmic such that the meter is less twitchy when adjusted as such. In mine the adjuster is situated under the battery cover just beside the battery. A small slot screwdriver turns it easily.

Re: action noise and suppressor hosts

Posted: Sun Sep 02, 2018 11:28 pm
by ECCO Machine
John A. wrote:That's a good idea of using a piece of plywood or paneling or something to just read the action noise. That makes a lot of sense actually.

Place the meter 3 foot away and there you go.

I've been thinking of getting one of those cheap db meters. I don't pretend that it would be as accurate as one costing hundreds or thousands of dollars, but should be able to tell if one is more quiet than another.
Maybe, but they don't have the sampling speed (rise time) or typically the frequency range to capture peak impulse SPL.

Keep an eye out for used older B&K meters. The 2209 is kind of a standard among older analog units, but some of the other models will have the range. I found a 2204 that was previously owned by McDonnel Douglas which has a 40-170 range. Just as important as the meter, though, (and often more expensive) is the microphone. Most of the meters you can find used have a more general purpose environmental noise mic on them.

Once you have a good impulse meter & mic, you can test with known quantities to evaluate it's calibration, and adjust the numbers a little bit within a limited range if it's close.

Of course, you're still talking at least $400-$500 for a decent old B&K meter plus used or maybe NOS mic of the variety you need (there are about a dozen 1/8", 1/4" and 1/2" B&K mic models that are suitable for high level, high frequency impulse noises). Based on my admittedly limited understanding, the 1/2" models aren't very suitable for accurate unsuppressed measurements, but can sample the lower levels of suppressed shots fine.

Re: action noise and suppressor hosts

Posted: Mon Sep 03, 2018 8:59 am
by doubloon
a_canadian wrote:Seems a fairly simple test to set up. A plywood sheet with a hole in the middle, rubber or heavy wool felt dam, poke the muzzle through and thread on a can. No way the suppressed shot on the other side of the plywood is going to meter as high as the action noise that way.
That would probably do it, no need to hand slap the bolt and get the full effect of any residual out-gassing around the chamber.

Re: action noise and suppressor hosts

Posted: Mon Sep 03, 2018 9:19 am
by doubloon
John A. wrote:...
I've been thinking of getting one of those cheap db meters. ...
Some random guy in a garage with a meter recently compared a Radio Shack meter to a Larson Davis and posted the results.

Where the B&K metered ~130 dB for an Anshutz air pistol the Radio Shack metered it at ~104 dB

https://docs.google.com/spreadsheets/d/ ... sp=sharing

Re: action noise and suppressor hosts

Posted: Mon Sep 03, 2018 1:04 pm
by Capt. Link.
At this point in time we must build a quieter machine.You don't need a sound meter for action noise.The difference is huge when you use a delrin pin to retain the bolt in a 10-22.Fixing the noise the bolt makes as it slams home has not yet been dealt with.Tying the rear of the action to the stock may help deaden the noise.A trigger/action job help with the snicks and clicks made when the hammer is set.
M-16 systems have the hammer hitting the pin noise and the buffer spring twang going on.The modular hammer/trigger systems and captured buffer springs may help both of those noises.
Action type makes a difference.I'll take a roller lock over any auto loader for suppressor use.A falling block is extremely quiet as are bolt actions.
Barrel choice...again the polygonal rifled barrel will be quieter than others.The why is better sealing results in a more complete powder burn and LOWER velocity due to friction.
Projectile speed is a major component,if you handload or are porting for speed control try 900 to 950 fps.The standard subsonic ammo is way to hot.
Barrel length and suppressor design needs to be matched not all long barrels are quiet suppressed.
The DeLisle action is fairly quiet,the British used bits of leather to quiet the bolt closing.
Lots of ideas out there post em if you got them!
-CL