bullet velocities ?

[shotgun 01]

OK, so this may sound kind of dumb, but why don't bullet manufacturers publish how they got the velocities that they publish? I would be interested to know how CCI arrived at 1070 for standard velocity .22s, or Wolf got 3240 from their Wolf Gold .223. What type of gun do I need to shoot to arrive at the published velocities? Inquiring minds want to know.

 

[GAgunLAWbooklet]

I agree. I wish they'd disclose the test barrel length and type of action (revolver vs. semi vs. single shot).

 

[davis211]

I wouldn't doubt some exaggeration going on either.

 

[rockyfatcat]

It depends upon a set of variables. A 9mm round through a handgun with a 3' barrel vs. the same round through a 16" rifle barrel. One can be easily stopped by a level two vest. The other can easily go through a level 3 vest.

The velocity achieved with the additional 13" of barrel length adds up. This is why a 9mm round through a revolver is such a bad idea. The gap between the cylinder and the barrel robs significantly from the rounds total performance.

The manufacturer can publish data on a round. They rarely let you know what the variables they used are. Bolt action, barrel length, even if they use the same variable to bench test and verify load data.

 

[cimino289]

Makes sense to include how data is obtained

 

[Bear44]

The manufacturers data is just a base line. A general idea of expectations. You can fire the ammo from two weapons that are the exact same model and manufacture of rifle or handgun and get different results. The only way to know what your actual velocities are is to chronograph the ammo from your weapon.

 

[rockyfatcat]

The manufacturers data is just a base line. A general idea of expectations. You can fire the ammo from two weapons that are the exact same model and manufacture of rifle or handgun and get different results. The only way to know what your actual velocities are is to chronograph the ammo from your weapon.

Different results? I would expect Similar results, not exactly the same, and certainly not wildly different.

 

[palmettomoon]

Too many variables. They'd have to publish altitude above mean sea level, ambient temperature, humidity, length of barrel, type rifling, distance from muzzle, type, model, calibration of chronograph, temperature of ammunition, rifle, etc. Then the lawyers' fees defending the inevitable suits from people with ammomaster chrony's and NEF single shot rifles that can't reproduce the same results. It's meant to provide you with a guide or idea of mmv. The better .22 ammunition suppliers test each lot from target test rifles so you get a more refined value. Reloading books used to supply the exact barrel length and even type of weapon but I haven't seen that published in some time. Would 20 fps difference make that much difference in your ballistic computer? Not being a smart ass, just shooter/reloader for 32 years.

 

[shotgun 01]

Yes, there are a lot of variables, however, I would bet that people contact them because they are not seeing similar results. If they are willing to print the velocity on the box, why not print the test gun also. It might save them some hassles. Of course, you would have to state that "mileage may vary," for those that don't know better.

 

[Bear44]

Different results? I would expect Similar results, not exactly the same, and certainly not wildly different.

I didn't say wildly different, but yes, different. You can even get different results from the same brand and type of ammo from the same rifle if the ammo manufacturing lots are different. The difference may not mean much to most shooters, but if you are looking for maximum accuracy, especially at long range, those differences are important.