New to black guns, need a little advice please
- Thread starter sgtblu
- Start date
No chamber or leades of the two barrels are cut exactly the same. A shorter leade will result in greater pressures because the bullet has less jump. When the bullet encounters the rifling, pressures peak. A longer leade effectively increases case volume just before that peak.
This is why it's unsafe to fire 5.56 NATO spec ammo in a true 223 SAAMI chamber. The 5.56 NATO chamber has a longer leade and a gentler angle where the bullet meets the rifling and 5.56 NATO spec ammo is loaded with more powder to make full pressure with that extra leade. When fired in a true 223 SAAMI chamber, the shorter leade means the bullet meets the rifling after a shorter distance and the effective case volume is too small for the powder charge used and pressure can peak at higher than acceptable levels.
It's also why 223 SAAMI spec ammo fired in a 5.56 NATO chamber results in reduced pressures and velocities.
It's possible the leade of your AR is shorter than the leade in the Howa.
Bottom line is differences chamber dimensions means a load that is safe in one rifle can develop dangerous pressures in another.
Note that few, if any, modern rifles are cut to true SAAMI dimensions. Most manufactures adjust the leade in their barrels to avoid dangerous pressures when 5.56 NATO ammo is used. 223 barrels are cut closer to 223 Wylde specs than 223 SAAMI specs
This is why it's unsafe to fire 5.56 NATO spec ammo in a true 223 SAAMI chamber. The 5.56 NATO chamber has a longer leade and a gentler angle where the bullet meets the rifling and 5.56 NATO spec ammo is loaded with more powder to make full pressure with that extra leade. When fired in a true 223 SAAMI chamber, the shorter leade means the bullet meets the rifling after a shorter distance and the effective case volume is too small for the powder charge used and pressure can peak at higher than acceptable levels.
It's also why 223 SAAMI spec ammo fired in a 5.56 NATO chamber results in reduced pressures and velocities.
It's possible the leade of your AR is shorter than the leade in the Howa.
Bottom line is differences chamber dimensions means a load that is safe in one rifle can develop dangerous pressures in another.
Note that few, if any, modern rifles are cut to true SAAMI dimensions. Most manufactures adjust the leade in their barrels to avoid dangerous pressures when 5.56 NATO ammo is used. 223 barrels are cut closer to 223 Wylde specs than 223 SAAMI specs
mj36639
New member
Originally Posted By: MistWolfNo chamber or leades of the two barrels are cut exactly the same. A shorter leade will result in greater pressures because the bullet has less jump. When the bullet encounters the rifling, pressures peak. A longer leade effectively increases case volume just before that peak.
This is why it's unsafe to fire 5.56 NATO spec ammo in a true 223 SAAMI chamber. The 5.56 NATO chamber has a longer leade and a gentler angle where the bullet meets the rifling and 5.56 NATO spec ammo is loaded with more powder to make full pressure with that extra leade. When fired in a true 223 SAAMI chamber, the shorter leade means the bullet meets the rifling after a shorter distance and the effective case volume is too small for the powder charge used and pressure can peak at higher than acceptable levels.
It's also why 223 SAAMI spec ammo fired in a 5.56 NATO chamber results in reduced pressures and velocities.
It's possible the leade of your AR is shorter than the leade in the Howa.
Bottom line is differences chamber dimensions means a load that is safe in one rifle can develop dangerous pressures in another.
Note that few, if any, modern rifles are cut to true SAAMI dimensions. Most manufactures adjust the leade in their barrels to avoid dangerous pressures when 5.56 NATO ammo is used. 223 barrels are cut closer to 223 Wylde specs than 223 SAAMI specs
Oh now you've done it Mistwolf. Stand by for a Banzai charge from the uninformed ".223 is absolutely identical to 5.56" crowd. Last time the bodies were stacked like cord wood in front of my position. I'll fill some more sandbags you get ammo.
PREPARE TO DEFEND YOURSELVES!!!
This is why it's unsafe to fire 5.56 NATO spec ammo in a true 223 SAAMI chamber. The 5.56 NATO chamber has a longer leade and a gentler angle where the bullet meets the rifling and 5.56 NATO spec ammo is loaded with more powder to make full pressure with that extra leade. When fired in a true 223 SAAMI chamber, the shorter leade means the bullet meets the rifling after a shorter distance and the effective case volume is too small for the powder charge used and pressure can peak at higher than acceptable levels.
It's also why 223 SAAMI spec ammo fired in a 5.56 NATO chamber results in reduced pressures and velocities.
It's possible the leade of your AR is shorter than the leade in the Howa.
Bottom line is differences chamber dimensions means a load that is safe in one rifle can develop dangerous pressures in another.
Note that few, if any, modern rifles are cut to true SAAMI dimensions. Most manufactures adjust the leade in their barrels to avoid dangerous pressures when 5.56 NATO ammo is used. 223 barrels are cut closer to 223 Wylde specs than 223 SAAMI specs
Oh now you've done it Mistwolf. Stand by for a Banzai charge from the uninformed ".223 is absolutely identical to 5.56" crowd. Last time the bodies were stacked like cord wood in front of my position. I'll fill some more sandbags you get ammo.
PREPARE TO DEFEND YOURSELVES!!!
Last edited:
sgtblu
New member
Well I returned from the range and I am happy to report I was able to obtain dime size groups using the Hornady Superformance .223 53 grain loads in my RRA Coyote Carbine, No FTF's or FTE's. Heading out later this afternoon to attempt to call in my first coyote for this season. PS, The BCM Gunfighter, model 4 works great! Thanks again everyone for the advise!!!!!!!
Originally Posted By: Mark2I understand what your saying. But are you saying that info Hornady posted is total bunk?
No. But the way it's written is misleading. According to the information given by Hornady, the 223 Superformance load holds peak pressure longer.
In the AR system, gas is diverted from the gas port to the gas tube to fill the expansion chamber inside the BCG (The Stoner AR system is not a direct impingement system, but that's a subject for another thread). When the carrier begins moving, the gas key of the carrier separates from the gas tube, cutting off the gas flow to the carrier. It's a self regulating system.
Before the gas can enter the BCG and come up to operating pressures, the bullet has exited the muzzle and blow down begins. Pressure inside the rifle does not drop the instant the bullet uncorks the muzzle. Gases continue to vent and pressure drops to atmospheric with time. It is the residual pressure that operates the rifle.
Because of the pressure curve of 223 Superformance, blowdown time is increased. A greater volume of gas enters the expansion chamber and accelerates the carrier at a greater than normal rate. The Superformance ammo causes the rifle to be over-gassed. That's why they suggest using an adjustable gas block on carbines. Longer gas systems mean their is less pressure at the as port reducing the over-gassing.
This extra blow down time will not cause popped primers. Loose primer pockets, excessive headspace (or ammo too short for the chamber), excessive pressure, soft brass or any combination of the above will.
Increased blow down will not cause primer cratering, primer flattening and shouldn't cause case case ruptures with new brass of the correct hardness fired in a properly dimensioned chamber
No. But the way it's written is misleading. According to the information given by Hornady, the 223 Superformance load holds peak pressure longer.
In the AR system, gas is diverted from the gas port to the gas tube to fill the expansion chamber inside the BCG (The Stoner AR system is not a direct impingement system, but that's a subject for another thread). When the carrier begins moving, the gas key of the carrier separates from the gas tube, cutting off the gas flow to the carrier. It's a self regulating system.
Before the gas can enter the BCG and come up to operating pressures, the bullet has exited the muzzle and blow down begins. Pressure inside the rifle does not drop the instant the bullet uncorks the muzzle. Gases continue to vent and pressure drops to atmospheric with time. It is the residual pressure that operates the rifle.
Because of the pressure curve of 223 Superformance, blowdown time is increased. A greater volume of gas enters the expansion chamber and accelerates the carrier at a greater than normal rate. The Superformance ammo causes the rifle to be over-gassed. That's why they suggest using an adjustable gas block on carbines. Longer gas systems mean their is less pressure at the as port reducing the over-gassing.
This extra blow down time will not cause popped primers. Loose primer pockets, excessive headspace (or ammo too short for the chamber), excessive pressure, soft brass or any combination of the above will.
Increased blow down will not cause primer cratering, primer flattening and shouldn't cause case case ruptures with new brass of the correct hardness fired in a properly dimensioned chamber