Rossi Rifleman

That's a nice looking boolit !

The "pugnose" 180 grain bullets from MBC are plain base & powder coated, and when weighed individually, run more like 195 -198 grains.

This might be an uneducated question, but why powder coat a gas checked bullet ? Is it just slicker running down the bore ?

They powder and gas check do different jobs. The powder takes the place of lube.

sandog wrote: Something else I wanted to try was checking the decibels of shots from .38 and .357 from both revolver and carbine.
No, I don't have a nice handheld meter, but I downloaded an app for my phone called Sound Meter.
Not sure of the accuracy but it seems sensitive.
My living room with a quiet fan reads at 48 decibels, and deep breaths next to the phone made it go up a couple decibels.

I tried to keep the phone in the same position under the muzzle for both handgun and long gun.
The .38 loads I tried in the S&W gave 100 decibels, and some Norma factory ,357 158 FMJs that get 1350 out of the handgun were 105 decibels.

Same loads out of the 16" Rossi were 90 for .38 Special and 95 decibels for the .357 ammo.
I would have thought that .357 ammo out of the 4 inch handgun would have been more like 130+ decibels but maybe my meter app is that far off.
At least the difference should be consistent using the same device on my guns.

Unfortunately as you've discovered, cell phone SPL meters are notoriously inaccurate (particularly for loud sounds). I'm an audio engineer and work with stadium-sized speaker systems. I've run across quite a variety of cell phone apps, usually being waved around by a guest who's upset that "It's too loud!".

The software is fairly simple to write, but as HarryAlonzo mentioned, the averaging circuits for the readings invariably round off or ignore small transient spikes.

However, the real crapshoot is the phone's hardware. Their microphones are designed for the human voice and that's about all. They invariably distort when presented with anything loud. Also, phones have automatic gain controls to adjust for the ambient noise level, and compressors to limit the dynamic range (which is why even relative readings on the same phone can be off). In addition, every phone does things differently within their operating systems before the signal even gets to the SPL software. (LOL)

If your phone has an 1/8" headset jack, try using an external microphone. Sometimes that bypasses the phone's internal gremlins.