All other things being equal, which has more muzzle blast -larger or smaller caliber?

[Unlicensed Dremel]

All other things being equal, which has more muzzle blast & louder report - a larger or smaller caliber?

For example, .242 win, .260 rem, 7mm-08 rem, .308 win - with same powder charge; which is loudest?

If I remember right, the smaller caliber is loudest, since the small bore "sharpens" or focuses the report, but cannot remember for sure.

[FrankenMauser]

Generally, a higher pressure cartridge is going to have more noticeable muzzle blast than a lower pressure cartridge.
Powder capacity matters, as well. But, all other things being equal, higher pressure = more noticeable pressure wave.

[Brian Pfleuger]

It's not so much the caliber that matters but the muzzle pressure.

Muzzle pressure is influenced by powder burn rate, peak pressure and barrel length, if not more.

I can run some examples in QuickLoad later on but the short answer is that there is no short answer.

[EchoM70]

The way I've always seen it and explained it; with all else being equal the smaller caliber will produce higher muzzle pressure thus producing a higher muzzle blast. So for example comparing a .243 to a .308 with everything else equal besides the bullet diameter the .243 will be louder than the .308.

[603Country]

We were shooting my 223 and my 260 the other morning. I was watching as a guest shooter shot each rifle. The 223, with a hot load of H335 under a 40 gr Nosler Ballistic Tip had a significantly larger muzzle flash than the 260 did. The 260 load is a warmish load of IMR4064 behind a 100 gr Nosler BT. I was quite surprised at the flash from the 223, and the 223 has a 2 inch longer barrel.

[WV_gunner]

Out of my guns, only one even has a muzzle flash. An AK pistol shooting Russian ammo with no brake. Puts out a ball of fire.

[Sierra280]

Are we strictly talking about rifle calibers? Because I've never seen a 38 load throw a huge ball of fire like hot 357 magnum loads.

And all things being equal: Fat people use more soap!

[PHEASANTPETE]

How can "All other things being equal, which has more muzzle blast -larger or smaller caliber?" be a realistic argument? What is equal between different calibers. Different calibers, pressures, how can one compare them equally? It is an odd question. Are you asking about higher pitch report? Smaller bores would generally produce a higher frequency. Lower frequencies from bigger bores.

Stand next to a magnum and they have a much louder report. How about a howitzer? Large bore and very loud albeit at a lower frequency, the kind that rattles your fillings loose.

Generally the more energy in the powder charge used the more of an energetic blast. Nothing new or shocking. If one wants to talk about perceived blast we can get into all kinds of rabbit trails. Muzzle brakes make the perceived blast to be greater because they redirect the blast towards the shooter. Kind of like standing in front of a speaker vs behind one.

Now if someone wants to discuss frequency blow across a big pipe and then a little pipe. Smaller pipes produce higher freqs. The energy released as sound at the end of the barrel will vary according to many factors.

What is the point of the question is what I wonder? You may get responses that better apply to your intended purposes if we knew what your reasoning was for asking the question.

[Unlicensed Dremel]

"all other things being equal" means pressure is equal. EVERYTHING else *besides* caliber is the same.

How can "All other things being equal, which has more muzzle blast -larger or smaller caliber?" be a realistic argument? What is equal between different calibers. Different calibers, pressures, how can one compare them equally?

It's not an argument. Just a question. Same pressure, same powder charge, everything. .260 rem with a 140 vs. .308 with a 140 loaded to the same pressure.

Perhaps the answer is "smaller". Perhaps it's "larger". Perhaps it's "the same". Perhaps the answer is "no one knows". I dunno; that's why I'm asking. But I thought I read once that the smaller the caliber the louder the boom, ceteris paribus.

[PHEASANTPETE]

The higher pitched smaller one may be perceived as louder as most hate high pitched noises. Listen to some young girls screaming and you get an idea of audio tolerance. The lower pitched one will carry further but which one is louder that would take some testing and mathematics to get an average.

[44 AMP]

I can't give you any kind of scientific explanation, only my observed results. I have Remington carbines in both .308 and .243, (equal barrel lengths) and my perception is that the .308 sounds "louder".

[bbqncigars]

The same powder charge in two different calibers will not develop the same pressure. Now if you're talking the same psi/fps/powder (which is more realistic), then in my limited experience it would be the smaller caliber. At least my .357AMP gives a lot more blast with the same load factors than my .44AMP. YMMV etc.

[Brian Pfleuger]

It's not an argument. Just a question. Same pressure, same powder charge, everything. .260 rem with a 140 vs. .308 with a 140 loaded to the same pressure.

The problem with that is that it's impossible.

The same charge of the same powder will not result in the same pressure in two different cartridges, even two that are based on the same parent.


For instance....

CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

According to QuickLoad,

A .260Rem loaded with a 150gr Sierra MK would max out at 42.3gr Ramshot Hunter. Muzzle pressure is 9,577psi, 60k PSI peak, mv 2,677 from 24".

A .308Win loaded with a 150gr Sierra MK and 42.3gr Ramshot Hunter...
Muzzle pressure 6,126 psi, 25k psi peak, mv 2222.

So, they're not even close.

You can't even fit enough Ramshot Hunter in a .308 case to get up to 60k psi with a 150gr SMK.

If I go the other way, a 96% charge of Wiin748 in the .308 gets us to 60k psi peak, 7,853psi muzzle and 2,975 mv.

That same charge is a .260Rem...

122,000 psi (blow up the gun, or darn near), 9,587 psi muzzle and (a staggering) mv of 3,270.

[44 AMP]

At least my .357AMP gives a lot more blast with the same load factors than my .44AMP.

Are they the same barrel length?