lenght of ammo

[brijendra]

does lenght of a ammo changes or varies the performance or the result on the target e.g. .32 bullets available in 3 forms 17mm, 21mm , 23mm.. i need answers !i m confused

[tingriman]

Hi brijendra,

The length of case is directly proportional to the amount of gun-powder a ctg hold, longer the length, more is the capcity for gun-powder, and more powder means more power for a ctg. BTW, 7.65x17 mm, 7.65x21mm and 7.65x23 mm are different calibres. They are not interchangeable. Please see the following link and say good bye to confusion

http://www.genitron.com/Basics/Cartridges.asp?NAV=2

cheers,
tingriman

[brijendra]

does it help in performance ? i mean longer the bullet , more pwerful it is?

[tingriman]

i mean longer the bullet , more pwerful it is?

simple answer yes, , as it might be holding more powder.


cheers,
tingriman

[TwoRivers]

Brijendra: First off, the "bullet" is the projectile. This term is unfortunately often misused for "cartridge". Think of the powder as stored energy. The more powder, the more energy will be released when the cartridge is fired. Lenght alone is not the determining factor, but cartridge volume. A shorter, but larger diameter case may well hold more powder than a longer, but slimmer case. But with cases of equal diameter, the longer one will hold more powder. So, if case volume is one factor, pressure is the other one in determining power. The higher the pressure, the greater the energy released for the same case volume. Rifle cartridges operate at much higher pressure than pistol cartridges. The longer the barrel, the more time the powder gasses have to accelerate the bullet, the higher the velocity, hence energy transferred to the bullet. Hope this helps answer your question. Cheers.

[xl_target]

does it help in performance ? i mean longer the bullet , more pwerful it is?

First of all, I think we have a terminology issue here.
A centerfire cartridge consists of a casing with a primer, propellant and a bullet. The bullet is the only thing that is propelled out of the muzzle. The entire assembly is called a cartridge.

Getting back to your question:
I think you are assuming that the longer the cartridge length, the more velocity and energy imparted to the bullet? Am I correct?

Well not necessarily. For example, there are some cartridges still in use today that were designed to use black powder as a propellant. Modern smokeless powders can generate more energy that black powder so some of our modern cartridges can equal or better the performance of those older cartridges even with a shorter cartridge length. It is important to know which specific cartridges you are talking about before you can make the assumption that you posted.

If the propellant being used for a certain caliber is the same, usually, the longer the cartridge length, the more energy imparted to the bullet. However, there can be a number of other factors that can result in better or worse performance like bullet shape and weight, barrel length, etc.

[tingriman]

brijendra,

Now you have both the versions of answer to your question. xl_target and two_rivers have excellently expalined things in detail.

cheers,
tingriman

[xl_target]

To confuse matters more, take a look at the last two items in the link that Tingriman posted.

Here you see that the 32-20 Winchester, even though it has more case capacity and a longer over all length, is out performed by the .327 Federal magnum. The .327 Federal cartridge is a new cartridge and the 32-20 is an older cartridge. As Two Rivers mentioned, chamber pressure has to be taken into account. Newer weapons can handle higher chamber pressures so the newer cartridge can be loaded to outperform the old one.

Sorry TwoRivers, I didn't see your post till I posted mine.

[MoA]

The over all length of a cartrudge can and often does vary even in the same caliber. The SAAMI and CIP publish reccomended OAL's for cartridges, based on the requirement for the cartridge to fit in any weapon of that particular caliber.
In the scenario of rifles in particular the OAL is often dictated by the requirement to fit and feed reliably from the magazine.
However if feeding from the magazine is not an issue, you can actually tailor the OAL to meet your requirements, including having the bullet touch the lands. A scenario that often will lead to a cartridge being well over the SAAMI/CIP OAL.
Even in pistols the profile of a bullet might dictate the OAL. A common example would be the OAL of a RN cartridge versus a wadcutter or semi-wadcutter. Even though the caliber is the same, the OAL of the cartridge will vary.