5.56x45mm vs .223 Remington

Thanis · June 24th, 2009, 02:18 AM

I'm far from a purchase, but just to increase my knowledge base, I was wondering.

I was told to purchase a 5.56x45mm chambered firearm, as the 5.56x45mm firearm can use either 5.56x45mm or .223 Remington, however the .223 Remington chambered firearm can not safely fire the 5.56x45mm round. I get the concept, as it is true, but I'm wondering about practically.

On average, does the 5.56x45mm firearm cost more? Is it available for civilian purchase? Is there a disadvantage to shooting a .223 Rem out of a 5.56x45mm chambered firearm (beyond the different ballistics of the rounds)?

I'm only starting serious consideration. I'm not sure about availability (of anything), still, always good to learn. Thinking an AR-15. I might wait till I hear more about FN scar (semi-auto version has a price tag, but just interesting all the barrel options and maybe caliber options). This is the first time I've heard about the 5.56x45mm vs .223 Remington consideration. Could use help past this part of the learning curve.

Blackeagle · June 24th, 2009, 02:24 AM

Quote:

Originally Posted by Thanis

On average, does the 5.56x45mm firearm cost more?

A gun's not going to cost more because it's chambered for 5.56, it's just as easy to cut a 5.56 chamber as it is a .223 chamber. However, you do tend to see 5.56 chambers in more 'serious' rifles, which are often a bit mroe price.

Quote:

Originally Posted by Thanis

Is it available for civilian purchase?

Yes.

Quote:

Originally Posted by Thanis

Is there a disadvantage to shooting a .223 Rem out of a 5.56x45mm chambered firearm (beyond the different ballistics of the rounds)?

No.

Thanis · June 24th, 2009, 02:28 AM

I forgot to also ask, is this good advise, go with a 5.56x45mm chambered firearm vs a .223 Rem firearm?

Blackeagle · June 24th, 2009, 02:33 AM

Quote:

Originally Posted by Thanis

I forgot to also ask, is this good advise, go with a 5.56x45mm chambered firearm vs a .223 Rem firearm?

Depends, what is this gun for? Is it going to be a plinker, or a paper puncher, or a game gun, or a serious fighting gun? .223 chambers are a bit more accurate, but they tend to be a bit more finicky, with more malfunctions. If we're talking about a self-defense gun, I'd definitely go with 5.56.

Ram Rod · June 24th, 2009, 05:55 AM

Surplus ammo is generally going to be more available in the 5.56mm. Assuming we are talking mainly about the AR-15 rifles here, it just seems to be more sensible to get the 5.56mm chamber. I don't notice any degradation in accuracy using .223 in my Bushmaster at 100yds or less with an 11 1/2" barrel. I don't know of any bolt actions made with 5.56 chamber. In this case, using 5.56 in a .223 rifle might have some risk as it has already been warned against. Then of course you always have those that come out and say they have done it with no ill effects. Those are the type of folks that make things dangerous for others, since others might rather listen to them than what makes sense, and put forth in black and white by the people who know. If you have a firearm that you plan on using both 5.56mm and/or .223, I'd go with the 5.56 chamber for sure.

rex03 · June 24th, 2009, 12:32 PM

I recently purchased a Stag Arms( You can see my thread in in this forum also) and it's chambered in 5.56. I too was skeptical about launching a 223 out of it. I did my research, and gave it a try, and it shoots wonderfully. I also took a look into the twist; as some say a 1:7 is optimal to shoot both, while mine is a 1:9 twist. I will say that the 5.56 seems a bit more accurate, but I like the option/availability to shoot two different round types. I do it , and will shoot a 223 if the 5.56 is unavailable, or if there is that much of a price difference on the ammo. I know it's a different topic also, but I recently got a Brownells 22LR conversion, and that is fun and cost pennies to shoot just to keep the trigger time in there also. Best of luck, and you'll find plenty of 5.56 rifle offerings out there, as they're more of the norm it seems nowadays.

BAC · June 24th, 2009, 02:56 PM

Most rifles with 1:9 twist barrels are actually chambered in .223, not 5.56 NATO. Some companies, like Rock River Arms, use a Wylde chamber, which is a hybrid falling somewhere between .223 Remington specs and 5.56 NATO specs; I don't know exactly what differences there are, just that it's supposedly safe to fire 5.56 NATO through them. Others, like Noveske, have slightly modified 5.56 chambers designed for shooting match-quality ammo like the Mk262. So far as I know, Noveske rifles have always been designed to shoot 5.56, so they're good to go. Consider having someone run a 5.56 reamer through it if you expect to shoot 5.56 ammo.

NATO specs call for the 5.56x45 chamber to have a longer leade than SAAMI spec'd .223 Remington chambers. A shorter leade means greater pressures. Additionally, while .223 Rem and 5.56 NATO have identical external dimensions, the case walls of the 5.56 are slightly thicker than that of the .223 Rem. Reloaders and gun rag writers like Glen Zediker estimate a combined 15,000 psi (or more) jump when using 5.56 NATO ammo in .223 Remington rifles.

-B

KevinDooley · June 25th, 2009, 12:59 AM

I think Timothy is a bit off base here - that big of a pressure jump can (and has) lead to barrels, uppers and what not busting and blowing out when firing high pressure 5.56 rounds in a .223 chamber.

Like BAC said, most 1:9 barrels (regardless of markings) are actually a .223 chamber. Unless you're going for a high accuracy gun I'd look for something with a 5.56 chamber and a 1:7 twist rate which will a. mostly guarantee that the 5.56 marking is valid and b. allow you to shoot 69gr and heavier(longer) bullets at all temperatures with no problems...

Thanis · June 26th, 2009, 04:37 AM

Thank you everyone.

Quote:

Originally Posted by KevinDooley

...most 1:9 barrels (regardless of markings) are actually a .223 chamber. Unless you're going for a high accuracy gun I'd look for something with a 5.56 chamber and a 1:7 twist rate which will a. mostly guarantee that the 5.56 marking is valid and b. allow you to shoot 69gr and heavier(longer) bullets at all temperatures with no problems...

Even better to know.

Ram Rod · June 26th, 2009, 05:40 AM

Bushmaster makes only 5.56 NATO chambers for their AR-15's. I have a 1/9 twist barrel. It's plainly marked.

June 24th, 2009, 02:18 AM	#1
Thanis Distinguished Member Join Date: Aug 2008 Location: MI Posts: 1,699	5.56x45mm vs .223 Remington I'm far from a purchase, but just to increase my knowledge base, I was wondering. I was told to purchase a 5.56x45mm chambered firearm, as the 5.56x45mm firearm can use either 5.56x45mm or .223 Remington, however the .223 Remington chambered firearm can not safely fire the 5.56x45mm round. I get the concept, as it is true, but I'm wondering about practically. On average, does the 5.56x45mm firearm cost more? Is it available for civilian purchase? Is there a disadvantage to shooting a .223 Rem out of a 5.56x45mm chambered firearm (beyond the different ballistics of the rounds)? I'm only starting serious consideration. I'm not sure about availability (of anything), still, always good to learn. Thinking an AR-15. I might wait till I hear more about FN scar (semi-auto version has a price tag, but just interesting all the barrel options and maybe caliber options). This is the first time I've heard about the 5.56x45mm vs .223 Remington consideration. Could use help past this part of the learning curve. __________________ NRA Member S&W 642 (no-lock) with .38 Spl +P 135 GR Gold GDHP Glock G31 & G33 with .357 Sig 125 GR. SXT Winchester Ranger

June 24th, 2009, 02:28 AM	#3
Thanis Distinguished Member Join Date: Aug 2008 Location: MI Posts: 1,699	I forgot to also ask, is this good advise, go with a 5.56x45mm chambered firearm vs a .223 Rem firearm? __________________ NRA Member S&W 642 (no-lock) with .38 Spl +P 135 GR Gold GDHP Glock G31 & G33 with .357 Sig 125 GR. SXT Winchester Ranger

June 24th, 2009, 05:55 AM	#5
Ram Rod VIP Member Join Date: Dec 2007 Location: crawford county, arkansas Posts: 8,643	Surplus ammo is generally going to be more available in the 5.56mm. Assuming we are talking mainly about the AR-15 rifles here, it just seems to be more sensible to get the 5.56mm chamber. I don't notice any degradation in accuracy using .223 in my Bushmaster at 100yds or less with an 11 1/2" barrel. I don't know of any bolt actions made with 5.56 chamber. In this case, using 5.56 in a .223 rifle might have some risk as it has already been warned against. Then of course you always have those that come out and say they have done it with no ill effects. Those are the type of folks that make things dangerous for others, since others might rather listen to them than what makes sense, and put forth in black and white by the people who know. If you have a firearm that you plan on using both 5.56mm and/or .223, I'd go with the 5.56 chamber for sure. __________________ RamRod-----sans remords live, eat, breathe, sleep Glock

June 24th, 2009, 12:32 PM	#6
rex03 Member Join Date: Jun 2008 Location: Florida Posts: 346	I recently purchased a Stag Arms( You can see my thread in in this forum also) and it's chambered in 5.56. I too was skeptical about launching a 223 out of it. I did my research, and gave it a try, and it shoots wonderfully. I also took a look into the twist; as some say a 1:7 is optimal to shoot both, while mine is a 1:9 twist. I will say that the 5.56 seems a bit more accurate, but I like the option/availability to shoot two different round types. I do it , and will shoot a 223 if the 5.56 is unavailable, or if there is that much of a price difference on the ammo. I know it's a different topic also, but I recently got a Brownells 22LR conversion, and that is fun and cost pennies to shoot just to keep the trigger time in there also. Best of luck, and you'll find plenty of 5.56 rifle offerings out there, as they're more of the norm it seems nowadays. __________________ --I'M PROUD TO HAVE THE ABILITY TO BEAR ARMS-- Glock27/ KaBar TDI/ MTAC Holster. I have more also, but this combo. works well..

June 24th, 2009, 02:56 PM	#7
BAC Distinguished Member Join Date: May 2007 Location: Tampa, Florida Posts: 1,980	Most rifles with 1:9 twist barrels are actually chambered in .223, not 5.56 NATO. Some companies, like Rock River Arms, use a Wylde chamber, which is a hybrid falling somewhere between .223 Remington specs and 5.56 NATO specs; I don't know exactly what differences there are, just that it's supposedly safe to fire 5.56 NATO through them. Others, like Noveske, have slightly modified 5.56 chambers designed for shooting match-quality ammo like the Mk262. So far as I know, Noveske rifles have always been designed to shoot 5.56, so they're good to go. Consider having someone run a 5.56 reamer through it if you expect to shoot 5.56 ammo. NATO specs call for the 5.56x45 chamber to have a longer leade than SAAMI spec'd .223 Remington chambers. A shorter leade means greater pressures. Additionally, while .223 Rem and 5.56 NATO have identical external dimensions, the case walls of the 5.56 are slightly thicker than that of the .223 Rem. Reloaders and gun rag writers like Glen Zediker estimate a combined 15,000 psi (or more) jump when using 5.56 NATO ammo in .223 Remington rifles. -B __________________ RIP, Jeff Dorr: 1964 - July 17, 2009. You will be missed. Defensive Carry Search Tips Step 1 - Choose a subforum on right side under "Search in Forum(s)" Step 2 - Type general topic of interest in "Search by Keyword" textbox. Step 3 - Read results and refine/repeat as necessary.

June 25th, 2009, 12:59 AM	#8
KevinDooley Senior Member Join Date: Feb 2008 Location: Texas Posts: 563	I think Timothy is a bit off base here - that big of a pressure jump can (and has) lead to barrels, uppers and what not busting and blowing out when firing high pressure 5.56 rounds in a .223 chamber. Like BAC said, most 1:9 barrels (regardless of markings) are actually a .223 chamber. Unless you're going for a high accuracy gun I'd look for something with a 5.56 chamber and a 1:7 twist rate which will a. mostly guarantee that the 5.56 marking is valid and b. allow you to shoot 69gr and heavier(longer) bullets at all temperatures with no problems... __________________ Quis custodiet ipsos custodes The will to win is worthless if you do not have the will to prepare. -Thane Yost

June 26th, 2009, 05:40 AM	#10
Ram Rod VIP Member Join Date: Dec 2007 Location: crawford county, arkansas Posts: 8,643	Bushmaster makes only 5.56 NATO chambers for their AR-15's. I have a 1/9 twist barrel. It's plainly marked. __________________ RamRod-----sans remords live, eat, breathe, sleep Glock

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