Magnum ammo reduced in power?

[cochise]

Since I'm retired, I can browse the web now. I was looking at some of the manufacturers specs on line and I see the .357 and .44 doesn't break 1300 fps anymore. I remember the average was around 1350 fps for 158 grn 357 and 1450 fps for 240 grn 44 mag.

I guess I don't have to worry about what I feed those old revolvers anymore.

 

[mtime7]

I think its do to the popularity of jacketed ammo. I only reload lead so I no expert on this but i think jacketed ammo doesn't get the same velocities

 

[handgunner356]

Some could be the use of vented barrels instead of test barrels to get you closer to actual handgun velocities.

 

[427mach1]

Way back when these calibers were introduced, the factory ammunition was chronographed using test barrels, which can be much longer than the typical revolver barrel. These longer barrels result in much higher velocities and the manufacturers publish these "optimistic" velocities. As chronographs have become more affordable and more shooting enthusiasts have begun chronographing with "real world" guns, the manufacturers have had to become a little more realistic in their published velocities.

 

[OKFC05]

I remember the average was around 1350 fps for 158 grn 357 and 1450 fps for 240 grn 44 mag.

Yes, in what were basically short rifle barrels that were not representative of a real revolver.
I agree the wide use of chronographs caused many people to complain about the science fiction, and the manufacturers went to shorter, vented test barrels that gave more realistic MV.

 

[stiab]

I agree with the previous posters about the primary difference being caused by the more realistic testing. There was an excellent article in the Aug/Sep edition of Handguns magazine which addressed this question. The .357 test barrel prior to the change was 10 inches long, unvented, with 8 3/8 inches of rifling. After the new SAAMI 1977 regulations were implemented, the .357 had to be tested in a 4" vented barrel.

It took a couple of years for the new numbers to get flushed through the published data and ads, but you can see it clearly in S&W ammo ads, with greatly reduced velocities across the board starting about 1979. When I compare before and after S&W ammo brochures, many .38 Special and .357 advertised velocities dropped 20% or more. The new ads proudly proclaimed that the velocites were from real guns, gave different numbers for 2", 4", and 6" barrels, and stated whether they were from a Model 10, Model 19, etc.

Edited to add: Oops! That was the Aug/Sep 2006 issue of the mag.