Which one is wrong?

[uncle norman]

On Winchester's web site it lists 44 mag Q4240 (240gr semi-jacketed soft point) at 1180fps and energy at 742ft/lbs. However, I chronoed 6 shots of the stuff and got an average velocity of 1,339 fps with a high of 1360 and a low of 1309. That puts the energy at 955ft lbs. Has anyone else clocked this stuff? (I'm concerned about readings I'm getting with my son's chronograph while I'm working up loads. If the chrony is right winchester is playing down their loading.)

 

[mkk41]

What was the barrel length of the test gun vs your gun?

 

[flop-shank]

What was the barrel length of the test gun vs your gun?

That, and keep in mind that different guns shoot faster or slower yet may have the same length barrel. Also, ammo makers load according to pressure not velocity, therefore velocity will vary from lot to lot.

 

[uncle norman]

Sorry. It is a Smith 629-6 Classic with 6 1/2" barrel. (I also chroned some Remington L44MG7, 180 gr rated at 1610fps. It clocked an average of 1594 out of my Smith. That's why I was surprised with the speed of the Q4240. I shot a really nice group but it's dirty.)

 

[handgunner356]

I must of got some from the same lot, avg 1382fps out of my 6" 629 Dlx.

 

[Steve C]

Essentially no one is wrong or both are right. You got the velocity from your gun under the condition you shot. Winchester got the velocity they published from the testing equipment they used.

US ammunition companies pretty much all list their velocity data for revolvers from a 4" vented test barrel since 4" is the more common barrel length and revolvers have a cylinder gap. Those specifically listed as hunting ammo ballistics may be from 6" or longer barrels and usually is stated as such. This was a change that occurred around 20 years ago in response to consumers that complained they did not get the advertised velocity out of their revolvers. Prior to the 80's most shooters had no access to a chronograph or any other way to easily measure muzzle velocity and the published loads where often from solid chambered test barrels of 8" or longer so velocities measured where a lot higher than what you see currently puplished. This is one of the main reasons people will mistakenly say that factory ammunition has been loaded down from what it was in the early days.

Measuring 1,339 fps from a 6.5" barreled revolver with a load that shoots 1,180 fps from a 4" barrel gun isn't unusual. ME of course is a function of the square of the velocity.

 

[uncle norman]

Yeah, but who wants to admit they blew a hog away with a 955 ft/lb load in a white box from..........Wally World! It just ain't right unless it's a special cooked up hand load. Yech. I'd feel dirty!

 

[Goodtime Charlie]

Since bullet performance is dependent upon velocity, if ammo manufacturers are loading to pressure and not velocity from lot to lot, then bullet performance is going to vary, too, unless bullet construction is changed each lot to match the different velocity. This could cause a JHP bullet to not penetrate to a sufficient depth, or to expand. This variance in bullet velocity in factory ammo can certainly explain the variance in performance of factory ammo in self-defense shootings. While bullets are designed by the manufacturer to expand within a certain velocity range, it seems to me that penetration depth will still vary with the bullet velocity, even if the bullet expands to the same diameter each time. If I'm figuring this wrong, please feel free to correct me.

 

[OKFC05]

Since bullet performance is dependent upon velocity, if ammo manufacturers are loading to pressure and not velocity from lot to lot, then bullet performance is going to vary, too, unless bullet construction is changed each lot to match the different velocity

You betcha!
That's why handloaders look down their collective nose at avg commercial ammo.

On the other hand, to be practical, at ordinary handgun distances it is not really that critical. Shot placement , you know.........

 

[flop-shank]

I doubt lot to lot velocity differences matter enough that bullet performance will be severely affected. Remember, velocity is one of many variables that comes into play every time there is a shooting, such as; fast shooting gun/slow shooting gun, barrel length, range, temperature, the shootee himself, barriers......... The list goes on and on and of course Erich's famous signature line factors into the equation everytime. Well designed bullets have enough fudge factor to perform well under a wide enough array of circumstances that lot to lot velocity variation is unlikely to make any significant difference. If it did, I would suspect that it would be in marginal calibers like the .380 or std. pressure .38 from a short barrel, not high velocity hard hitters like the .357 magnum.

 

[uncle norman]

Essentially no one is wrong or both are right. You got the velocity from your gun under the condition you shot. Winchester got the velocity they published from the testing equipment they used.

US ammunition companies pretty much all list their velocity data for revolvers from a 4" vented test barrel since 4" is the more common barrel length and revolvers have a cylinder gap. Those specifically listed as hunting ammo ballistics may be from 6" or longer barrels and usually is stated as such. This was a change that occurred around 20 years ago in response to consumers that complained they did not get the advertised velocity out of their revolvers. Prior to the 80's most shooters had no access to a chronograph or any other way to easily measure muzzle velocity and the published loads where often from solid chambered test barrels of 8" or longer so velocities measured where a lot higher than what you see currently puplished. This is one of the main reasons people will mistakenly say that factory ammunition has been loaded down from what it was in the early days.

Measuring 1,339 fps from a 6.5" barreled revolver with a load that shoots 1,180 fps from a 4" barrel gun isn't unusual. ME of course is a function of the square of the velocity.

Thanks, Steve. That would explain the difference if it holds that each inch of barrel adds about 100fps. (By the way, my son lives in Gilbert and we love to go to the Usery Mountain range when we visit him. Two months ago the day before we got there a LEO shot himself in the right leg holstering his piece in some kind of competion. He didn't clear his .40 first. Had you heard anything about that?)

 

[stiab]

the published loads where often from solid chambered test barrels of 8" or longer so velocities measured where a lot higher than what you see currently puplished. This is one of the main reasons people will mistakenly say that factory ammunition has been loaded down from what it was in the early days.

I agree. When S&W ammo was advertised using "industry standard test equipment" they claimed 910 fps for their 158 grain RNL. Starting with the 1979 ammo brochure, using a "Model 10 4" barrel" their claimed velocity dropped to 675 fps. Both of the above quotes came directly from their ammo advertisements. When I have time I'll post a more complete comparison of before and after the change from using long and unvented test barrels to using real guns, showing all their .38 Special and .357 mag loads. Folks who believed (or still believe?) the hype from the old pre-1978 test numbers were being significantly mislead by the industry.

 

[Steve C]

By the way, my son lives in Gilbert and we love to go to the Usery Mountain range when we visit him. Two months ago the day before we got there a LEO shot himself in the right leg holstering his piece in some kind of competion. He didn't clear his .40 first. Had you heard anything about that?

I live on the other side of town and don't shoot at Usery. Hadn't heard about the accident. In the big city it doesn't even make the papers. I usually do my outdoor shooting at PRG (Phx Rod and Gun) or Ben Avery Range and indoors at Shooters World.