The quietest calibre for roe (Scotland)

[doric_prince]

Probly you would get just as quiet as 22cal by using good (or even execptional) caliber specific mod and reduced load. Meaning the difference would not be noticeable given everything else that affects how the noise from shot is judged (time of day, weather, direction of shot etc.)

Obvious way to get reduced loads is developing a suitable homeload, but there's even factory stuff like Hornady Custom Lite (87gr SST @ 2800fps) that seems to be available in UK (but maybe not in stock at the moment). Of course 2500fps with fast powder would be quieter still.

I will try the lower factory loads first, if I can find them. The mod I have is a good quality high noise reduction model albeit in a bigger calibre (although I dare not disclose the brand for fear of causing an upset on SD ).

 

[jthyttin]

I don't think you get best results with 30cal mod. Furthermore, you say it's magnum model and some manufacturers try to achieve magnum rating by enlargening the bullet hole. Especially if the internal volume is on the low side. Maybe gauge the hole size with e.g. drill bits (or something else that's available in reasonable length and different diameters) and go from there?

 

[muddy42]

I've shot 243 and 223 moderated. Yes the 223 with be technically quieter (eliminating other variables) but I doubt human ears could really tell. Personally if you have a 243 already, you'd be better replacing the .30 cal mod with a tighter fitting mod and with maximum noise suppression.

If you reload and are only shooting roe in Scotland, you could also get quite close to replicating a 223 anyway - lighter bullet and take your pick on the velocity, keeping it just over the various 'deer legal' requirements for roe deer in Scotland. Let's not go into it here - plenty of info online or other threads on this topic!

 

[Edinburgh Rifles]

6mm bored moderator with the biggest chamber you can tolerate on a .222
223 second best to the mighty treble

Ran one on golf courses with houses 10-15yds away from the shot
very quiet

But....note to the nerds
regardless of powder volume or calibre, the vast majority of Deer legal calibres produce unmorderated peak decibel levels of within 2-23dB of each other
verified by a £10k Brüel & Kjær 2250-S sound analyser during our 2018 moderator test!!

Reviews and Tests – Edinburgh Rifles

• "Unmoderated shots from .308, .270, .25-06 and 6mmBR all registered within less than 2dB of each other, an average peak of between 165-166.9 dB, despite a powder charge range of 30-60gr"

 

[jthyttin]

Ed, you should really test for first shot only, since there's significant difference in most cases. And other tests do not show a significant difference if the first shot is "first shot ever through the moderator" or "first shot of string" (you mention first shot through unfired mod).

 

[Heym SR20]

Barrel length makes a huge difference to noise. With an 18” barrel you will still have a lot of unburnt powder which will exit the barrel and continue burning. Burning front of powder is about 5000 fps.

But with a 26” barrel most of the powder is fully burnt so no further powder still to burn so much less of a boom.

Moderators slow down the gases, but with a slower starting speed a longer barrel will be quieter.

 

[Edinburgh Rifles]

Ed, you should really test for first shot only, since there's significant difference in most cases. And other tests do not show a significant difference if the first shot is "first shot ever through the moderator" or "first shot of string" (you mention first shot through unfired mod).

Single data set of anything is a waste of time
We fired minimum five shots and took a mean

Some mods were new, some well used, some barley used
The first shot through brand new mods was louder every time
That would skew results

The mean peak dB range is the only significant way to demonstrate any pattern

 

[Edinburgh Rifles]

Barrel length makes a huge difference to noise. With an 18” barrel you will still have a lot of unburnt powder which will exit the barrel and continue burning. Burning front of powder is about 5000 fps.

But with a 26” barrel most of the powder is fully burnt so no further powder still to burn so much less of a boom.

Moderators slow down the gases, but with a slower starting speed a longer barrel will be quieter.

Actually in the cases above we fired 20” to 26” it made no difference
All unmoderated
All within less than 2dB

 

[jthyttin]

E.g. this German test I linked in the other thread shot 3pcs "first shots". The procedure is described in the last page (red box) and first shot data is kept separate from "following shots".

- first shot and 4 following shots
- cooling by pressurised air etc.
- another first shot and 4 following shots
- cooling
- 3rd first shot

https://www.frankonia.com/images/multimedia/pdf/schalldaempfer-caliber-4-2021.pdf

 

[Heym SR20]

Actually in the cases above we fired 20” to 26” it made no difference
All unmoderated
All within less than 2dB

But remember that dB scale is not a liner scale but a logarithmic scale and is measuring the energy of a sound wave. So a difference in 2 dB between two barrels means that there is difference in the energy of the sound wave of 10^2(0.1), so a rise in 2dB means an increase in power of the sound wave by 1.5 times.

In other words your ears get a 50% increase in sound energy for a 2dB increase in sound.

 

[wildfowler.250]

6mm bored moderator with the biggest chamber you can tolerate on a .222

Why would you use a 6mm mod rather than a .22 cal mod in the .222? Asking out of confusion rather than trying to be smart

 

[Kjf]

Shush / stalking / quiet

Bang!!!

It didn't hear me ,

Lol.,

No calibres are quiete , not worth bothering about ,

Squeeze the trigger, the quarry don't know the difference, ( neither will the neighbours) only you do ,,

And that's not worth a discussion , lol

Just shoot mucker don't over think.things

Kjf

 

[scrumbag]

Actually in the cases above we fired 20” to 26” it made no difference
All unmoderated
All within less than 2dB

Quick question: Did you fire say a .243W in a 20" and a 24" barrel for example?

If they are different chamberings, you can't really say that your data tells us much about barrel length.

The DB reading, fairly close to the muzzle, is a measure of peak intensity, rather than overall energy in the system. Where you might see more of a difference is at 50m / 100m / 200m where I suspect a 30-06 might well register more than a .222 due to gas volumes released.

Scrummy