if someone has a .243 winchester , a .308 win and a .30-.30
I'd be interested in seeing them side by side

(pictures with rulers or half inch grid graph paper get extra credit)


thanks in advance

not my picture but this is .243 - .308 - 30-30

You'll see that the 243 is simply a 308 case necked down to .243.

thanks a bunch ,

there seems to be a difference in the primer ends,

I wonder why that is?

quote:

Originally posted by bendable:
there seems to be a difference in the primer ends,

I wonder why that is?

.30-30 is a "Rimmed" cartridge, where the rim of the case at the primer end protrudes past the edge of the case walls. This is how many early rifle cartridges were designed, and most revolver cartridges. These cartridges headspace off the rim, meaning the rim is what correctly positions it within the chamber, ensuring that it doesn't go in too far.

More modern cartridges like .308/.243 are designed to be what is considered "Rimless" (even though they do have a rim for the extractor to engage). It's just that the rim is flush with the level of the case walls. These cartridges headspace off the "shoulder" of the cartridge instead, towards the bullet end of the case where the case narrows, and don't require a wide rim to control insertion depth into the chamber.

These Rimless cartridges are significantly more common these days, mainly because they can be easily used in box magazines, without the worry of the wider rims of Rimmed cartridges catching on each other and hanging up during feeding. This is why nearly all .30-30 rifles and rifles chambered in revolver cartridges like .44 Magnum or .357 Magnum are tube-fed instead of using a detachable box magazine. And is why it's tougher to design something like a .357 Magnum semiauto pistol, since the magazine has to be specially engineered to be able to feed Rimmed revolver cartridges without the wide rims catching on each other.

There are also a few other styles of rim, including "Semi-Rimmed", where the rim is only slightly wider than the case walls, and "Rebated Rim", where the rim area is noticeably narrower than the case walls.

quote:

Originally posted by RogueJSK:

quote:

Originally posted by bendable:
there seems to be a difference in the primer ends,

I wonder why that is?

.30-30 is a "Rimmed" cartridge, where the rim of the case at the primer end protrudes past the edge of the case walls. This is how many early rifle cartridges were designed, and most revolver cartridges. These cartridges headspace off the rim, meaning the rim is what correctly positions it within the chamber, ensuring that it doesn't go in too far.

More modern cartridges like .308/.243 are designed to be what is considered "Rimless" (even though they do have a rim for the extractor to engage). It's just that the rim is flush with the level of the case walls. These cartridges headspace off the "shoulder" of the cartridge instead, towards the bullet end of the case where the case narrows, and don't require a wide rim to control insertion depth into the chamber.

These Rimless cartridges are significantly more common these days, mainly because they can be easily used in box magazines, without the worry of the wider rims of Rimmed cartridges catching on each other and hanging up during feeding. This is why nearly all .30-30 rifles and rifles chambered in revolver cartridges like .44 Magnum or .357 Magnum are tube-fed instead of using a detachable box magazine. And is why it's tougher to design something like a .357 Magnum semiauto pistol, since the magazine has to be specially engineered to be able to feed Rimmed revolver cartridges without the wide rims catching on each other.

There are also a few other styles of rim, including "Semi-Rimmed", where the rim is only slightly wider than the case walls, and "Rebated Rim", where the rim area is noticeably narrower than the case walls.

To add a little bit to this - headspacing off the rim means the chamber dimensions don't have to be quite as exact (which was helpful given manufacturing technology 125 years ago when the .30-30 Winchester cartridge was designed) and also means the extractor geometry is a lot less critical and feeding is easier (again, manufacturing 125 years ago).

In 1906, Remington designed the .30 Remington cartridge, which is more-or-less a rimless .30-30 Winchester, for its box magazine fed semiautomatic Remington Model 8 rifle.

The .30 Remington has been dead for a while - as far as I know, new factory ammunition hasn't been made for it for maybe 40 years - which is a shame, because I actually have my grandfather's, or maybe great-grandfathers, Model 8 in .30 Remington.

The Model 8 was chambered in several other cartridges, including .35 Remington, which still enjoys limited popularity as a brush/woods cartridge and is still produced.

quote:

Originally posted by YellowJacket:
You'll see that the 243 is simply a 308 case necked down to .243.

It's worth noting that the .308 Winchester is the parent case for more currently popular cartridges than probably anything else.

Just by necking down, we get the .243 Winchester (6mm), .260 Remington (6.5mm), 7mm-08 Remington (.284), and just by necking up, we get the .338 Federal (8.6mm) and .358 Winchester (9.1mm).

If you allow changing the shoulder geometry a bit (the place the case abruptly tapers down to the bullet diameter), there are a bunch more - for example, in 6.5mm/.264, the 6.5 Creedmoor and 6.5x47 Lapua are both pretty much .308 cases with the shoulder pushed back (making the case shorter). The reason for this change was so you could load the cases with the long, heavy bullets used for long-range shooting and still have the cartridges fit in standard-sized magazines.

quote:

Originally posted by RogueJSK:

quote:

Originally posted by bendable:
there seems to be a difference in the primer ends,

I wonder why that is?

.30-30 is a "Rimmed" cartridge, where the rim of the case at the primer end protrudes past the edge of the case walls. This is how many early rifle cartridges were designed, and most revolver cartridges. These cartridges headspace off the rim, meaning the rim is what correctly positions it within the chamber, ensuring that it doesn't go in too far.

More modern cartridges like .308/.243 are designed to be what is considered "Rimless" (even though they do have a rim for the extractor to engage). It's just that the rim is flush with the level of the case walls. These cartridges headspace off the "shoulder" of the cartridge instead, towards the bullet end of the case where the case narrows, and don't require a wide rim to control insertion depth into the chamber.

These Rimless cartridges are significantly more common these days, mainly because they can be easily used in box magazines, without the worry of the wider rims of Rimmed cartridges catching on each other and hanging up during feeding. This is why nearly all .30-30 rifles and rifles chambered in revolver cartridges like .44 Magnum or .357 Magnum are tube-fed instead of using a detachable box magazine. And is why it's tougher to design something like a .357 Magnum semiauto pistol, since the magazine has to be specially engineered to be able to feed Rimmed revolver cartridges without the wide rims catching on each other.

There are also a few other styles of rim, including "Semi-Rimmed", where the rim is only slightly wider than the case walls, and "Rebated Rim", where the rim area is noticeably narrower than the case walls.

To add a little bit to this - headspacing off the rim means the chamber dimensions don't have to be quite as exact (which was helpful given manufacturing technology 125 years ago when the .30-30 Winchester cartridge was designed) and also means the extractor geometry is a lot less critical and feeding is easier (again, manufacturing 125 years ago).

In 1906, Remington designed the .30 Remington cartridge, which is more-or-less a rimless .30-30 Winchester, for its box magazine fed semiautomatic Remington Model 8 rifle.

The .30 Remington has been dead for a while - as far as I know, new factory ammunition hasn't been made for it for maybe 40 years - which is a shame, because I actually have my grandfather's, or maybe great-grandfathers, Model 8 in .30 Remington.

The Model 8 was chambered in several other cartridges, including .35 Remington, which still enjoys limited popularity as a brush/woods cartridge and is still produced.

grateful for all the info , thank you for taking the time to enlighten me.

necking down a rifle cartridge:
https://www.youtube.com/watch?v=isCae4HVVQc

would the rim end of the 30 -30 pictured above make it much better for a lever action than a bolt action set up ?

Better for a lever actions of many design. Rimmed cases can and are used in bolt actions, but often don't feed as smooth and have "rim lock" issues. (basically the rims catching on each other)


Then of course you have the .30 Remington, which is just a 30-30 with a rimless case head to make it work better in their pump and semi auto. (.32 Remington being the same in relation to the .32 Winchester Special)