223 vs 556...new question

maifire

maifire

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Yes, I can literally hear your eyes rolling. This isn't however an issue of compatibility. Does anyone have genuine knowledge on accuracy between the two? Specifically, I noticed the Hornady superperformance 77gr offerings. Only difference is .223 or 5.56. I am shooting a 1:9 twist. You?
Forgive me if this is a repeat, I could not find a thread...and being honest, I cannot see how it isn't.
 
1/9 twist might or might not stabilize 77gr.

have a savage 1/9, great with 69gr hpbt, terrible with 75 gr and 77g match.

same with r700.


only way to findout is to try a box in your rifle.
 
The difference is in the Chamber, not the Cartridges. A given 5.56 Cartridge may have a slightly bigger charge, but that only matters if the bullet is marginally stable, driving it that little bit harder may be all that's needed to stabilize it.

So that out of the way, heavy Projectiles, and 1 in 9". You should be able to shoot Hornady 75 gr Match, and Sierra 77 gr MK's, and as LFD stated 69 gr SMK's are ideal. The problem with 1 in 9' twist barrels is they will barely stabilize most of the projectiles over 68 gr. The two that will most likely work are the 69 gr SMK, and the Hornady 75 gr Match. Anything with a G1 over 0.350 is likely going to give you problems at Sea Level, and/or in cold weather...and why I'm going to load up some 69 gr this morning.

Try and get a copy of Applied Ballistics For Long Range Shooting by Bryn Litz, it explains it all in great detail.
 
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Appreciated. I will have to try. In the end, the minor velocity change looks irrelevant, it will just come down to the weight of the bullet. Curious as well, the 5.56 states *not for use in .223 chambers. A catch-all phrase, i suppose, for liability-though i am well aware of the chamber/pressure relationship.
Oddly or not, my rifle performs nicely with the hornady steel match in 75gr.
 
The Ops question is certainly a loaded one.

Its like asking what's faster a Ford or Chevy.

There's long range accuracy and short range accuracy. We need to be clear which.

Its hard to speculate what would shoot best in a particular rifle, but the 1:9 is good for nothing heavier than a 75 or maybe 77 grain projectile like the 77 SMK or TMK.
 
maifire said:
It was not an intention to load the question. My intention was mentally justify why they make a duplicate round. 223 can fire in a 556 chamber. Seems pointless if they shoot the same.

And of course, Ford is faster.
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Mil spec vs civvy spec. Differences in how they measure pressure when they determine pressure ratings of the respective cartridges.

Some older .223 rifles 'may' not be strong enough to handle hot 5.56 or that might be overblown.

Civvy spec will be more accurate. Because that's what civvy sho oters care about.

The most accurate ammo for *your* rifle will be the reloads you make.
 
redshooter said:
The difference is in the Chamber, not the Cartridges. A given 5.56 Cartridge may have a slightly bigger charge, but that only matters if the bullet is marginally stable, driving it that little bit harder may be all that's needed to stabilize it.

So that out of the way, heavy Projectiles, and 1 in 9". You should be able to shoot Hornady 75 gr Match, and Sierra 77 gr MK's, and as LFD stated 69 gr SMK's are ideal. The problem with 1 in 9' twist barrels is they will barely stabilize most of the projectiles over 68 gr. The two that will most likely work are the 69 gr SMK, and the Hornady 75 gr Match. Anything with a G1 over 0.350 is likely going to give you problems at Sea Level, and/or in cold weather...and why I'm going to load up some 69 gr this morning.

Try and get a copy of Applied Ballistics For Long Range Shooting by Bryn Litz, it explains it all in great detail.
Click to expand...

Hello there,

With everything said and done, what distance are we talking about when one will start to see the diff. between the diff. type of loads and ammo?
Are we talking beyond 300m? 400m? or beyond? Are the diff. noticeable up to 200m?

Thx
 
maifire said:
Still not clear on why there would be a 5.56 offering. The 223 would be able to be fired in all chambers and is saami recognized.
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There is a 556 offering for firearms with 556 chambers. Yes 223 will work but you won’t get optimal results. The freebore is different between the cartridges.

I fired “Independence” 556 ball ammo from a CZ 18.5” bolt gun and got 3400fps. I’d imagine shooting 223 in a 556 chamber in some instances might not work that great.
 
Here's a pretty good write-up about 5.56 vs .223 cartridges and chambers: h ttps://www.thetruthaboutguns.com/5-56-vs-223/ Most newer firearms with 1:9 twist barrels have chambers with a longer leade that can safely fire 5.56 ammo but check with your manufacturer's specs to be sure.
 
My Savage Hog Hunter is a 20" contoured 1 in 9 twist got this 119 yard group shooting in a bit of wind off my bipod with 75 grainers. I have shot 556 in my Savage with no challenges.

My mag only holds 4 shots, I messed up on the fourth shot, my Army buddy always let's my Savage cool down between shots, he is a way better shot.


 
Disco Bob said:
Hello there,

With everything said and done, what distance are we talking about when one will start to see the diff. between the diff. type of loads and ammo?
Are we talking beyond 300m? 400m? or beyond? Are the diff. noticeable up to 200m?

Thx
Click to expand...

It can be measured, I had a load I worked up using 223 data for my HBAR, and one using a different powder and 5.56 data. About 2700 fps vs. 2800 fps. Referring to my Ballistic Program, with a 100 m zero, you can see a difference as early as 200 m, but it's very small, 0.5 cm. I don't believe there's any real practical difference though unless you're trying to poke holes in Helmets at 600 m.
 
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