Rimfire and Centerfire

Heckler · 24-02-2015 12:26am #1

This may well be a question I should know the answer to.

I understand the difference between both. Where the firing pin hits, where the primer is, can't reload .22s because the striking surface is crushed..

But why isn't there a centerfire .22 ? What is it about a .22 in particular that makes it a rimfire ? Why not take a .22 bullet and put it on a centerfiring casing designed to fit it ?

Obviously I'm missing something blatant.

Witcher · 24-02-2015 12:30am

Heckler wrote: »

This may well be a question I should know the answer to.

I understand the difference between both. Where the firing pin hits, where the primer is, can't reload .22s etc.

But why isn't there a centerfire .22 ? What is it about a .22 in particular that makes it a rimfire ? Why not take a .22 bullet and put it on a centerfiring casing designed to fit it ?

Obviously I'm missing something blatant.

There are centrefire .22's; .220 Swift, .22-250, .223 etc.

The term '.22' really just refers to the bullet diameter, you can get a 40 grain .22lr round and a .220 Swift 40 grain round, they're both '.22's' (with tiny difference in diameter) but they're just shaped differently- one round nose bullet and one spitzer. The Swift also has a big oul milk bottle behind it.

Heckler · 24-02-2015 3:08am

Strider wrote: »

There are centrefire .22's; .220 Swift, .22-250, .223 etc.

The term '.22' really just refers to the bullet diameter, you can get a 40 grain .22lr round and a .220 Swift 40 grain round, they're both '.22's' (with tiny difference in diameter) but they're just shaped differently- one round nose bullet and one spitzer. The Swift also has a big oul milk bottle behind it.

Just when I thought I had a basic grasp on ballistics. Oh well.....

EWQuinn · 24-02-2015 6:10am

"But why isn't there a centerfire .22 ? What is it about a .22 in particular that makes it a rimfire ? Why not take a .22 bullet and put it on a centerfiring casing designed to fit it ?"

They had that same idea back in the 1920's. So they invented the .22 Hornet center fire, driving a 45 gr .22 bullet 2,700 fps instead of the .22 LR driving a 40 gr bullet 1,200 fps. The first of the high velocity, center fire .22's. Now there are a bunch of them with large bottle neck cases driving pointy bullets up to and over 4,000 fps in some.

The first mass produced full bore cartridges in the US in the mid 1800s were rimfire which quickly evolved into center fire.

extremetaz · 24-02-2015 11:11am

Heckler wrote: »

Just when I thought I had a basic grasp on ballistics. Oh well.....

http://en.wikipedia.org/wiki/List_of_rifle_cartridges

if you can think of it, there's probably been some attempt at it somewhere at some time.

clivej · 24-02-2015 11:33am

Also you can only push a lead bullet so fast. The lead starts to strip off in the barrel, heat build up on the bullet head as it goes down the barrel, etc.
The HV rounds have a copper wash on them as the speeds are greater. I don't know if that's why they have it on though.

yubabill1 · 24-02-2015 2:03pm

clivej wrote: »

Also you can only push a lead bullet so fast. The lead starts to strip off in the barrel, heat build up on the bullet head as it goes down the barrel, etc.
The HV rounds have a copper wash on them as the speeds are greater. I don't know if that's why they have it on though.

The copper jacket is indeed to stop melting at the bullet/barrel interface at higher velocities.

The high velocity .22LR Stinger (c.1600 fps) has a copper jacket for just this reason, as does the Yellow Jacket (c.1400 fps), I think.

.22LR ammo is really cheap to produce, partly because the primer is contained in the rim, which is formed by a "bump" during manufacture.

.22 centrefires require a separate primer and a primer receptacle machined into the bullet case, adding to cost.

nearest thing to centrefire .22LR might be 5.7 x 28 from FN, (also 4.6 x 30 from HK, but that's .17 diameter). Both are similar to .22 Magnum in performance, but with enhanced characteristics for reliability and efficacy.

juice1304 · 24-02-2015 2:07pm

stigers dont have a jacket it is only a copper wash.

yubabill1 · 24-02-2015 2:59pm

juice1304 wrote: »

stigers dont have a jacket it is only a copper wash.

Looks electroplated to me. That's a jacket IMHO.

juice1304 · 24-02-2015 5:55pm

a jacketed bullet is different it is a lead core swedged into a copper case or "jacket".

yubabill1 · 24-02-2015 7:27pm

That's a cup-and core, or pointed soft point in old money.

I don't know how the Stinger is manufactured, but I have seen the copper jacket partially separate - not often - from the lead core on recovered pills.

As I said, it looks electroplated, but either way, the copper can partially separate from the lead core, but it sticks really well.

I don't know what a copper wash is, but I do not know another way to bond copper to lead chemically and the jacket is way too thin to join mechanically.

OK, I googled this - think someone posted link to this article on boards previously:

"Unlike many lubricated-lead bullets of the time, the 32-grain Stinger bullet was copper plated, accomplished through an electro-chemical process. Even though the technology was in use since the 1930’s, it still was not a simple process for mass production."

meathstevie · 24-02-2015 8:09pm

yubabill1 wrote: »

The copper jacket is indeed to stop melting at the bullet/barrel interface at higher velocities.

The high velocity .22LR Stinger (c.1600 fps) has a copper jacket for just this reason, as does the Yellow Jacket (c.1400 fps), I think.

.22LR ammo is really cheap to produce, partly because the primer is contained in the rim, which is formed by a "bump" during manufacture.

.22 centrefires require a separate primer and a primer receptacle machined into the bullet case, adding to cost.

nearest thing to centrefire .22LR might be 5.7 x 28 from FN, (also 4.6 x 30 from HK, but that's .17 diameter). Both are similar to .22 Magnum in performance, but with enhanced characteristics for reliability and efficacy.

Beg to differ on 5.7 and 4.6 from FN and H&K, those little nasty fast ones have been designed as to do to light body armour what traditional pistol calibers can't.

The logic behind the likes of a P90 and an MP7 is near assault rifle capability in a compact package.

Some compromise compared to proper rifles had to be accepted when it comes to longer range accuracy but the bullet design allows for far greater accuracy over distance than traditional pistol ammo submachine guns or handguns while still penetrating stuff a pistol or revolver round gets stuck in.

yubabill1 · 24-02-2015 8:34pm

meathstevie wrote: »

Beg to differ on 5.7 and 4.6 from FN and H&K, those little nasty fast ones have been designed as to do to light body armour what traditional pistol calibers can't.

The logic behind the likes of a P90 and an MP7 is near assault rifle capability in a compact package.

Some compromise compared to proper rifles had to be accepted when it comes to longer range accuracy but the bullet design allows for far greater accuracy over distance than traditional pistol ammo submachine guns or handguns while still penetrating stuff a pistol or revolver round gets stuck in.

Agreed there are dedicated AP rounds for 5.7 and 4.6, but other ammo is available for civilian use.

Also forgot to mention that 5.7 and 4.6 designed to give good results from short barrels.

Personally, I'm very happy with my 223 and see the 5.7 and 4.6 as rounds with specialised applications.

meathstevie · 25-02-2015 12:37am

yubabill1 wrote: »

Agreed there are dedicated AP rounds for 5.7 and 4.6, but other ammo is available for civilian use.

Also forgot to mention that 5.7 and 4.6 designed to give good results from short barrels.

Personally, I'm very happy with my 223 and see the 5.7 and 4.6 as rounds with specialised applications.

That's exactly what they are and both FN and H&K as far as I know reserve the full auto versions and AP ammo strictly for police and military use.

yubabill1 · 25-02-2015 9:49am

meathstevie wrote: »

That's exactly what they are and both FN and H&K as far as I know reserve the full auto versions and AP ammo strictly for police and military use.

http://www.thefirearmblog.com/blog/2013/10/16/5-7x28mm-body-armor/

meathstevie · 25-02-2015 10:22pm

yubabill1 wrote: »

http://www.thefirearmblog.com/blog/2013/10/16/5-7x28mm-body-armor/

All in all an interesting discussion but I think we're drifting a bit

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Rimfire and Centerfire

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