Help: Confusion as to Noise Levels

Jump to latest Follow Reply
M

Mannyrock

Member
Sep 3, 2019
1
0
VA
Hi Guys,

I need some help please. 

I had a walnut stocked Sheridan Blue Streak, 5mm, that my dad bought for me in 1970, for $38.00. I kept that rifle for about 45 years, and it was a pretty hard shooter, but I finally got really sick and tired of pumping that forum 4 times to get it up to speed. So, I sold it for $150.

Since then, I have always lived in very rural areas, or had land I owned close by, so that I could shoot a .22 whenever I wanted, even off my back deck.

Now, at 65, I am about to move to a house on a 5 acre lot. There are about 20 yards of heavy oak around all four sides of the lot, but on the other side of those lines, there are big houses about 100 yards away.

I am very experienced in shooting CCI CG Longs, and recently, the CCI Quiet 22 longs in my rifle., just for fun. But, I the Quiet 22 rounds do make some noise, which do sound like gunshots, so I figured, "What the heck, its time to get an air rifle. It's got to be quieter."

I am thinking about getting a Hammerli 850, which shoots the .22 14 grain pellets at bout 650 fps, creating only about 13 foot pounds of energy. Before buying, I decided to check out information on its sound decibels.

Wow. What a surprise. Most of the info I can find online says that the Hammerli has about 86 decibles of sound per shot. Why am I surprised? Because the online information about the .22 Quiet rounds says that they are only putting out about 62 decibels per shot, and that is for a 40 grain lead bullet traveling at 750 fps and generating 40 foot pounds! Is this data just all wrong? Has anybody got any other data or experience on this?

Thanks,

Mannyrock




























 
Air guns vary significantly in the noise produced. Many of the PCP rifles come with moderators which have some affect in reducing the noise. You have a fairly large lot and am surprised that the hemmerli CO 2 rifle is as loud as a CCI quiet round which I have shot and which does still have a significant crack to it. I’m hard pressed to think that the air rifle is as loud . It may be.

Have you considered a spring piston gun like the HW 30 urban pro (air guns of Arizona). I have one and I’d think it would work well for you and you would avoid the cost of the CO2 cartridges. Easy to cock and accurate and I would think certainly quiet enough . Some of the high power spring guns can crack pretty loudly as well. The physics of pushing a pellet at higher velocity requires more air and therefore more noise. 
 
Upvote 0
No experience with the low power/quiet .22lr rounds but you prob watch/listen to TV at more than 62db. I'm sitting a foot from a 12" fan in an enclosed room an I'm getting 57db. Then I put my beer can down and it peaked at 76db. (This is from a cell phone ap.). CO2 and HPA guns have a different 'crack' sound but they are easy to tame down. We like the term 'LDC' for lead dust collector but they are sound moderators. 

I'm on 13 acres but the shape of the lot is odd and there are 2 houses within 200y (different directions) from where i shoot and they can not here my guns. I have good LDC's. But I should add that they CAN hear the pellet impact from each shot, even on paper.... It just doesn't scream GUN SHOT, just thwack....
 
Upvote 0
shopI have 2 Hammerli 850's and there is no way they are at 86 DB at 1 meter

most CO2 guns have a certain noise level, a crack to them

they make a muzzle brake for a 850

https://www.pyramydair.com/s/a/Umarex_Compensator_Fits_Hammerli_850_Walther_1250_Dominator_Beretta_CX4_Rifles/1135

the barrel is 15mm, now that muzzle brake doesn't quiet the 850 down at all but the sleeve you put on it does, black tape to metal sleeve, my choice will make you wonder if you are out of CO2, it is that quiet

and talking about CO2 if you buy a 850 get a 2 x 12gr adapter

shop for the best price on the brake
 
Upvote 0
Hi Mannyrock, 

So the subject you're about to dive feet first into is.... very VERY complicated. If you're the technically inclined sort, I'd be happy to launch into what'd have to be a many paragraph long dialogue. This is my personal diatribe on the subject: https://www.airgunnation.com/topic/fx-crown-bespoke-moderator-tesla-gas-diode/

The short version though is that the reason why these numbers seem nonsensical is that they're lying like a lion. The way sound is measured and reported is a system absolutely ripe for abuse. Decibels are a logarithmic scale, that means add ten decibels to something and it is TEN TIMES the pressure level, add twenty decibels and it is a hundred times. But double the distance from the noise source and you cut the decibels by about 6, and position can significantly affect it as well. This is why standards are very very important. Further, most sound meters aren't capable of capturing the very short peak sound produced by airguns and firearms, in fact I have NEVER seen someone apply an appropriate and properly calibrated meter in a standard testing protocol on an airgun. (no the Extech AEAC uses doesn't work, and in fact if you read the manufacturer's documentation they explicitly say it won't work) 

So, in short, don't listen to the numbers, my experience metering firearms suggests the ".22 quiet rounds meter 65dB" sounds like it came hot and fresh out the back side of a horse. My experience with the Aguila Colibri is that they are much quieter than the 40 grains and are still louder than a properly suppressed airgun. For your application if you can form1 a firearm suppressor, that might be a perfectly fine solution. Unfortunately most of the firearms industry suppressors are not optimized for ultimate silence, and so do muffle the report substantially but aren't exactly super quiet and still make a gunshot sound. A good moderator on a nice PCP airgun will be quieter than the quietest rimfire I've ever metered, and there are a wide variety of after-market mods I've tested which will do a good job bringing the report down. In that endless thread I posted you can find those results on page 5:
https://www.airgunnation.com/topic/fx-crown-bespoke-moderator-tesla-gas-diode/page/5/#post-453278



I hope that helps. This all is a lot to digest, and is a subject we regrettably have very little good data on. If you have any other questions, please feel fee to ding me and I'll try to answer them as best I can. 
 
Upvote 0
Upvote 0
How far to your nearest friendly airgun person? Would be the #1 choice for getting real world information whether a match or an individual. We're in the 99109 zip code should that help and most folks are equally welcoming to new people.

As far as the model you mention I've no DB #'s but have seen and used several versions from stock to wild. Personally would pick a QB but that's just me. If it suits you and you use the factory compensator linked above with mentioned "mod" (wrap/seal tube) you will have no issue with sound.

It is an effective unit being well aligned with an exit dia. to small for a .25 and a decent volume it works a charm and has been doing so since before any silencing device could be openly purchased and still equals some of the best for less money and weight. Also makes a 20fpe QB78 (with 15mm barrel) silent.

Do get with another airgunner(s) if at all possible.



John
 
Upvote 0
Hi Manny, I have owned two Hammerli 850s and they are much quieter than a subsonic .22. However, I have neighbors and I did put a moderator on each of them. I bought the LDCs from Brackeenairworks Custom Airgun Work <[email protected]> from Austin. I think they cost about $50, were well machined, and did not affect accuracy. Austin answered my emails promptly and was great to work with. The 850 is a great entry into air gunning as CO2 is cheap at Walmart and mine shot Crosman Premier Domed 177 caliber Pellets which you can order from Walmart at about $7 for 500. I shot squirrels out to 45 yards with good reliability.
 
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu