The sound of a pellet impact and Urban friendly air rifles.

I have been shot at by a break barrel pellet gun. This guy I got in a fight with decided to get revenge on me while I was getting off the bus. I watched him load it up and thought (oh sh** ) so I started running and he missed me by I'm guessing a foot or so. Thank god he's a crappy shot lol! To answer the question its a little louder than you would think, and it's a high pitch pop kinda noise

I would say my Taipan mutant is the quietest out of the box PCP I have ever owned, plus it is really zinging those pellets out at 920 to 930 fps.

For absolute stealth in my back yard during the warmer months, I use my modded Co2 Crosman .22 Ratcatcher with Weihrauch LDC. It is putting out about 9-10 ft Ib's, but it is so quiet with the Weihrauch LDC on it.

It's hard to compare, without a test environment. I guess for apples to apples comparison, I would start with Paul Capello's Airgun Reporter reviews through Pyramyd Air. He has a pretty stable test environment and a lab grade sound pressure meter.

My anecdotal experiences are below:

My Weihrauch HW30s springer is pretty quiet, but still much louder than my 1st generation Marauder .177. (stock) With the Marauder, I've shot squirrels in the backyard while the neighbors were in their yards, and they didn't even notice the sound of the gun over the noise of the cicadas. The squirrel hitting the ground was by far the loudest noise.

With a nice quiet rifle, a neighbor would only hear a muffled pop (which could be anything) and the sound of the pellet hitting the target; which just sounds like a 'TIK' when it's paper, or a bit louder 'WHOK' when it hits a fur-bearing animal. Pellet impact on a bird is quieter.

My friend had a custom PCP gun, I think it was a BSA R10 that had been quieted down even further by the airgunsmith. It was so quiet, there was literally NO perceptible sound of the pellet leaving the barrel. Just a super quiet 'CHK' of the trigger being tripped, followed by the impact of the pellet. (a 16 gr .22 @ 900 fps)

After having just listened to your Marauder pistol, I can say that if I were a neighbor, I wouldn't think twice about it, unless I heard a bunch of shots in a row.

I own a .25 caliber WARized Mrod, with a tensioned and shrouded barrel. It is regulated and has an SSG. I can shoot it within 5 feet of livestock (cattle and/or horses), and none will respond.

In the back yard the pellet hitting the target is always louder than the muzzle report. I think the real key here is the SSG which keeps excess air from escaping the barrel. 

The most quiet out of the box gun I ever heard was the Cricket. 

Air Gun Exploration and Advancement said in a review "there's quiet then there's Cricket quiet" Sounds like a pneumatic brad nailer to my ears Quieter than the Marauder

One of my co-workers has a really quiet P-Rod, quiet enough the neighbors are none the wiser. However, anytime he clicks off a round, the neighbors DOGS have learned that sound means, "It's party time!" and come a runnin' to "help" with the squirrel problem. LOL

Generally it is the backstop that is the loudest. I had plywood setup and it sounded like an air driven staple gun, 'THWAP!' Ballistic rubber is fantastic and quiet as well as safe.

My .22 AirArms TX200 was louder than any of my 22 PCPs. And the pos .177 WalMart or Dick's guns that boast 1300fps will make a sonic crack. PCP is where it's at, but vary as much as cars do in features and audible report. All my stuff has a Huggett on the end.

What is your main concern about how loud the air rifle is? Noise nuisance, complaining neighbors, not wanting to draw attention, or something else?

There are a lot of reasons why one air rifle may be louder than another. Items that may affect sound include caliber, design, manufacturing, action, amount of air used, pellet selection, target, shooting area, and more. Based on the model you're looking at you can change the sound simply by choosing a smaller caliber and/or adjusting how fast the pellet leaves the barrel. A .177 pellet going at 650 fps will not be as loud as a .177 traveling at 1200 fps. And in many cases, a .177 traveling at 800 fps is going to be quieter than a .25 going 800 fps. If you don't like how loud the air rifle is, try adjusting how much air is being used to propel the pellet, try different styles of pellets If that still isn't working, you may be able to add more baffles or add on a moderator/LDC provided the air rifle can support that. Another option is to just replace the air rifle with a different one.

I've got two Hugget moderators and a Neil Clague LDC. The Hugget's are on a .25 Compatto and a .22 Regal while the LDC is on an .25 S510. By far, the S510 is the quietest followed by the Regal with the Compatto coming in last. However, each air rifle is very quite in its own right and as Smaug stated, the "WHOK" and "THAWCK" of the pellet hitting the animal/bird could be more of a sound concern than the discharge of the air rifle.