Muzzle blast

[Xbolt]

How dose the loudness of the 7mm rem mag compare to the 338 win man and 300 win mag or even the 458 win mag since they are all based on the same casing should they be in the same level?

[darkker]

Unfortunately it doesn't work that way, exactly.
Muzzle blast, in terms of sound, has to do with pressure in the barrel at the time of bullet exit; thus the "BOOM", or "POP" sound. So barrel pressure at exit is what counts mostly. THAT is determined by powder choice, and amount used.

So to give you a little more on this. The slower burning a propellant, the less complete burn is likely to happen(unless using a VERY progressive powder). This will tend to push the pressure curve farther along the firing event, and have a higher muzzle pressure upon bullet exit. The higher the pressure at bullet exit, the bigger the boom. To give you an idea, a 30-06 with a 150-class bullet will have muzzle exit happen somewhere around 1.4 milliseconds. Depending upon powder and barrel length of course, this will leave you with a muzzle pressure of 15-20,000psi. That is assuming a chamber operating pressure around 60,000psi(cartridge operational pressure).

The 7mm I believe has an operational pressure of 62-65,000 psi. With the same length barrel as an '06 the muzzle pressure will be higher. I don't know the operational pressures of the other cartridges.

Cheers!