223 Wylde

[DRJ]

I'm old and have been away from AR's for quite a while so could anyone explain the 223 Wylde to me. I have researched it but came away confused and now I have a rifle stamped 223 Wylde. Thanks for any help.

[26 Inf]

I'm old and have been away from AR's for quite a while so could anyone explain the 223 Wylde to me. I have researched it but came away confused and now I have a rifle stamped 223 Wylde. Thanks for any help.

Let me give it a shot. First of all, as I understand there is no dimensional difference between the .223 and the 5.56 cartridges themselves. The .223 cartridge spec'ed by SAAMI for a max chamber pressure of 55,000 PSI measured in the body of the case; the military 5.56, chamber pressure is measured at the case mouth, I believe this equals a chamber pressure of 62,000 if it were measured in the same manner as the SAAMI specifications. Since these are max pressures, it could be unsafe to fire higher pressure 5.56 cartridges in a .223 chamber.

Here's why: the military desired higher velocities from the 5.56 than the .223 Remington it evolved from, the military also wanted the ability to fire heavier bullets through the M16/M4, these bullets are normally longer than the bullets the .223 was designed around. In order to accomplish this the military changed the chamber of the .223 by slightly increasing the amount free bore and leade at the end of the chamber.

The freebore and leade on a .223 chamber is .085 inch; the freebore and leade on the 5.56 is .162, nearly twice as long. This gives the higher pressure, sometimes longer 5.56 projectile sufficient distance to allow pressure to drop to a safe level before the projectile engages the rifling when fired in a 5.56 chamber. If the same 5.56 cartridge were to be fired in a .223 chamber, a longer projectile may actually contact the rifling before firing. If this occurs a dangerous pressure spike can occur. It is safe to fire .223 in a 5.56 chamber, it could be unsafe to fire 5.56 cartridges in a .223 chamber.

So what the heck does this have to do with the .223 Wylde? Well, when the M16 was adopted for service rifle competition, folks wanted to be able to shoot heavier (longer) 77 grain bullets. These same folks thought that the 5.56 chamber did not fullfill their needs in terms of accuracy, so hybrid chambers were developed, among them the .223 Wylde. The .223 Wylde has a slightly longer and tighter freebore than the 5.56 and, of course, the .223 round.

It is safe to fire both 5.56 and .223 in .223 Wylde chambers, think of it as a match chamber.

Okay, someone tell me where I goofed.

[davidz71]

I thought the Wylde chamber had a shorter distance to the rifling than the 5.56 clambering but longer than the .223 chambering.

[ace4059]

I thought the Wylde chamber had a shorter distance to the rifling than the 5.56 clambering but longer than the .223 chambering.

To sum up the Wylde chamber, this is correct.

[Onyx Z]

The 223 Wylde chamber is basically a 5.56 chamber/throat (to safely fire 5.56 ammunition) with the 223 Rem's .224 bore.

It has nothing to do with longer bullets and a mostly to do with enhancing precision/accuracy. Think of it as a "match chamber".

[DRJ]

Thanks everyone for the info. I was just totally confused about the Wylde.

[lysander]

Let me give it a shot. First of all, as I understand there is no dimensional difference between the .223 and the 5.56 cartridges themselves. The .223 cartridge spec'ed by SAAMI for a max chamber pressure of 55,000 PSI measured in the body of the case; the military 5.56, chamber pressure is measured at the case mouth, I believe this equals a chamber pressure of 62,000 if it were measured in the same manner as the SAAMI specifications. Since these are max pressures, it could be unsafe to fire higher pressure 5.56 cartridges in a .223 chamber.

None quite.

People talk of 'military 5.56mm' as if there was single pressure limit for all military loadings. There is not.

The M193 family has a maximum allowable average pressure of 55,000 psi, with a plus three sigma pressure of 61,000 psi.

The M855 family currently has a maximum allowable average pressure of 58,700 psi, with a plus three sigma pressure of 64,700 psi. Prior to 1999, the pressures were 55,000 psi, with a plus three sigma pressure of 61,000 psi, respectively.

The M855A1 family currently has a maximum allowable average pressure of 62,000 psi, with a plus three sigma pressure of 66,000 psi.

All of these pressures are currently measured with conformable pressure transducers calibrated against pierced case, direct reading, pressure transducers. This is the same method used by most commercial ammunition manufacturers.

Here's why: the military desired higher velocities from the 5.56 than the .223 Remington it evolved from, the military also wanted the ability to fire heavier bullets through the M16/M4, these bullets are normally longer than the bullets the .223 was designed around. In order to accomplish this the military changed the chamber of the .223 by slightly increasing the amount free bore and leade at the end of the chamber.

Basically correct, but the reason the military chose a longer lead was to keep the maximum chamber pressure down, without loosing velocity, not the desire to use different bullets.

The freebore and leade on a .223 chamber is .085 inch; the freebore and leade on the 5.56 is .162, nearly twice as long. This gives the higher pressure, sometimes longer 5.56 projectile sufficient distance to allow pressure to drop to a safe level before the projectile engages the rifling when fired in a 5.56 chamber. If the same 5.56 cartridge were to be fired in a .223 chamber, a longer projectile may actually contact the rifling before firing. If this occurs a dangerous pressure spike can occur. It is safe to fire .223 in a 5.56 chamber, it could be unsafe to fire 5.56 cartridges in a .223 chamber.

I think you just aren't explaining it well. The longer leade, or free bore, allows the bullet to get a "run and go" at the rifling, so the work required to engrave the rifling is less. It has to do with the way propellant burns and the way it reacts to the pressure it generates. Long leades do not "allow pressure to drop to a safe level before the projectile engages the rifling", it keeps the pressure from reaching high levels in the first place.

Unless you have a really fat ogive, or have loaded the bullets extremely long, the bullet will not contact the rifling before firing.

Short leads mean short bullet jump, which leads to better accuracy, which is why SAAMI chose the shorter leade.

So what the heck does this have to do with the .223 Wylde? Well, when the M16 was adopted for service rifle competition, folks wanted to be able to shoot heavier (longer) 77 grain bullets. These same folks thought that the 5.56 chamber did not fullfill their needs in terms of accuracy, so hybrid chambers were developed, among them the .223 Wylde. The .223 Wylde has a slightly longer and tighter freebore than the 5.56 and, of course, the .223 round.
It is safe to fire both 5.56 and .223 in .223 Wylde chambers, think of it as a match chamber.

Okay, someone tell me where I goofed.

Bill Wylde designed the chamber as a compromise between the accuracy of the the SAAMI chamber and the long leade military chamber so you could get the best of both, accuracy comparable to the .223 Remington chamber and still shoot military loads without excessive pressure. As a fortunate side effect was the ability to used heavy bullets with a long seat.

[siniestro02]

wow thanks for the info. I have one too and I wasn't sure if I could shoot 5.56 we well.

[26 Inf]

None quite.

People talk of 'military 5.56mm' as if there was single pressure limit for all military loadings. There is not.

The M193 family has a maximum allowable average pressure of 55,000 psi, with a plus three sigma pressure of 61,000 psi.

The M855 family currently has a maximum allowable average pressure of 58,700 psi, with a plus three sigma pressure of 64,700 psi. Prior to 1999, the pressures were 55,000 psi, with a plus three sigma pressure of 61,000 psi, respectively.

The M855A1 family currently has a maximum allowable average pressure of 62,000 psi, with a plus three sigma pressure of 66,000 psi.

All of these pressures are currently measured with conformable pressure transducers calibrated against pierced case, direct reading, pressure transducers. This is the same method used by most commercial ammunition manufacturers.


Basically correct, but the reason the military chose a longer lead was to keep the maximum chamber pressure down, without loosing velocity, not the desire to use different bullets.


I think you just aren't explaining it well. The longer leade, or free bore, allows the bullet to get a "run and go" at the rifling, so the work required to engrave the rifling is less. It has to do with the way propellant burns and the way it reacts to the pressure it generates. Long leades do not "allow pressure to drop to a safe level before the projectile engages the rifling", it keeps the pressure from reaching high levels in the first place.

Unless you have a really fat ogive, or have loaded the bullets extremely long, the bullet will not contact the rifling before firing.

Short leads mean short bullet jump, which leads to better accuracy, which is why SAAMI chose the shorter leade.


Bill Wylde designed the chamber as a compromise between the accuracy of the the SAAMI chamber and the long leade military chamber so you could get the best of both, accuracy comparable to the .223 Remington chamber and still shoot military loads without excessive pressure. As a fortunate side effect was the ability to used heavy bullets with a long seat.

Thanks man. I knew I'd learn!

[Gabriel556]

I did a pretty lengthy search because I swear I saw Molon had a huge post about the chamber differences between .223, 5.56 and .223 Wylde......

Maybe not though.