Muzzle velocity questions?

[KABA]

Is there a industry standard for determining muzzle velocity for a given caliber and bullet weight?

Is there any regulation and/or oversight for publshed data on ammunition?

If there is no standard, do ammo manufactuers typically inflate their velocity numbers?

How much of a velocity loss is involved in using a short barreled firearm such as a 2.75" barrel on a mouse gun?

Short barreled pistols and revolvers are seemingly becoming more popular with CCW becoming more common. I admit a total lack of knowledge on this but it would seem that a given round that might provide adequate penetration or expansion in say a 6" barrel might be marginal in a 2.75" barrel.

Thanks for your responses.

 

[boatbod]

I chronographed some .22LR rounds out of my 3.8" bbl Beretta 87BB

CCI MiniMag - 930fps actual. Mfr quoted 1235fps
CCI Stinger - 1150fps actual. Mfr quoted 1640fps.

So yes, shorter barrels do have an appreciable impact on attainable MV, especially if you happen to be shooting a "rifle" round in a pistol. Probably the difference would be less with dedicated pistol rounds, because I'm led to believe they utilize faster burning power.

Others more knowledgeable are sure to chime in.

 

[esq_stu]

There's no standard definition of "mouse gun," so I doubt it would do you any good to look up velocities for mouse guns an an ammo manufacturer's site. Many of the ammo manufacturers websites do state the barrel length with their data, but mouse gun owners are out of luck.

 

[steveno]

ammo manufacturers load to a pressure. they try to get to the advertised velocity but pressure is more important

 

[Brad Johnson]

Is there a industry standard for determining muzzle velocity for a given caliber and bullet weight?

No. The standards are for cartridge dimension and allowable pressure, both of which are safety issues. Once dimensions and pressures are set, the cartridge is tested from a standardized barrel to determine ballistics.

Is there any regulation and/or oversight for publshed data on ammunition?

SAAMI

If there is no standard, do ammo manufactuers typically inflate their velocity numbers?

Typically, no. However, spec barrels will not be faced with operational, longevity, or feeding reliability issues. As a result the chambers are usually cut to exact spec (i.e. very "tight"). This means mfgs measurements can be, and often are, slightly higher than consumers see in the field.

How much of a velocity loss is involved in using a short barreled firearm such as a 2.75" barrel on a mouse gun?

Depends on the caliber and manufacturer.

Short barreled pistols and revolvers are seemingly becoming more popular with CCW becoming more common. I admit a total lack of knowledge on this but it would seem that a given round that might provide adequate penetration or expansion in say a 6" barrel might be marginal in a 2.75" barrel.

Again, completely dependent on caliber and manufacturer.

Brad

 

[KBintheSLC]

Is there a industry standard for determining muzzle velocity for a given caliber and bullet weight?

Is there any regulation and/or oversight for publshed data on ammunition?

If there is no standard, do ammo manufactuers typically inflate their velocity numbers?

How much of a velocity loss is involved in using a short barreled firearm such as a 2.75" barrel on a mouse gun?

1 - check out http://www.saami.org/

2 - I believe that most testing is done internally.

3 - Yes, I believe they do a little.

4 - Velocity loss in short barrel pistols is significant compared to the same ammo out of a 16" carbine for example. For short carry guns, it's always good to use +P.

 

[brickeyee]

To produce the highest pressure test barrels usually have minimum chambers and tight bores.
They want to ensure that firing the ammunition in ANY gun will not result in unsafe pressure.
The pressure, and the velocity. are thus almost always less with OEM equipment, unless you got a lucky 'tight' chamber or barrel.

 

[mpmarty]

Some ammo manufacturers go to extremes such as 32" "test" barrels with transducers and tight chambers. Basically what has been said here before is correct, the ammo is designed to fit a standard chamber and function at safe pressure levels within standard parameters when fired in normal firearms chambered for the particular cartridge. Temperature is one variable that tends along with bore condition and chamber dimensions to create variables in pressure and to a lesser extent velocity. Remember, we are speaking of pressure as the peak pressure obtained in firing. Velocity is more dependent on duration of peak or near peak pressures than the absolute peak pressure. If it were possible to obtain forty or fifty thousand pounds per square inch of pressure for the entire "trip" down the rifle barrel we would see some amazing velocity figures. Unfortunately, particularly in bottleneck overbore cartridges the pressure peaks early and drops precipitously during the bullets travels down the barrel. You might want to look up some interior ballistics references at a library or online. Very interesting stuff and frustratingly, the best performing projectiles for interior ballistics are the worst performing for exterior ballistics (after the bullet leaves the muzzle).