223rem/5.56nato

buzzmagoo

buzzmagoo

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Here we go I imagine that you have answered this question before. Whats the real difference between them?I have heard that 5.56 is a hotter load,the primers are harder and need a harder and deeper strike, the bullets are larger diameters,the case shoulders not the same ,then my fav the head stamp aaaa! My reason for asking being I am thinking of getting a new( cal to me) rifle target model and the manufacturer states 223 only while for the same model the plane Jane. one its will take 223 and 5.56. Could you in your with infamously wisdom and tac give me a straight answer please! And while on the subject the same for 308/7.62. And you have beautiful eyes and an engaging smile ( a little gratuitous flurtation never hearts):cool: thanks!
 
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Flattery will get you everywhere lol!

**Disclaimer** always read your gun manufacturer's manual. That supersedes all information written here!

You're pretty much right with your information. The neck of the 5.56mm is longer, 5.56mm brass is thicker, and the 5.56mm tends to be loaded to a higher pressure. They both take the same size projectiles. Those are some of the key points, there are more of course. The long and the short of it is that mostly you can use 223 Rem ammunition in a 5.56mm rifle, but you should never use 5.56mm ammunition in a 223 Rem rifle.

What you're looking at in a rifle - the type of shooting you wish to do, whether you want an AR-15 or not, versatility of ammunition available etc - will dictate which rifle you will choose. I am sure other people in this forum will have opinions on what's best!
 
I'm no expert, but I'll take a stab at this.


223 and 5.56 cartridges are pretty much identical externally. The chamber of a 5.56 gun will be more generous than a 223 chamber, a "target" gun chamber will be the tightest (hence 223 only). 5.56 usually has a longer throat (greater distance to lands) to accommodate heavier bullets in the 80-90gr range, this can be an issue if your expecting very tight groups from a light for caliber bullet as there will be a significant jump to the lands. They all use .224 diameter projectiles. 223 can always go into a 5.56 chamber without any worry, 5.56 can often safely go into a 223 chamber but not always. I would not shoot 5.56 from a target gun marked 223.


.308/7.62 is the opposite of .223/5.56. Commercial 308 hunting ammo will be hotter than 7.62x51 Nato ammo. 308 is 60,000psi while 7.62 Nato is 50,000psi, although they measure the pressure differently (copper crush washer vs pressure transducer). The head space is also different between the two along with internal case capacity (7.62 has thicker brass meaning less internal volume). 7.62 Nato can be safely fired from any 308 chamber. If using 308 in a 7.62 Nato gun, make sure you check the headspace first. Further, the pressure curve for 308 may not agree with the gas system on some semi Autos like the M1, this can cause anything from accelerated wear of the moving parts to failure to cycle properly or even catastrophic failure of the firearm in extreme cases. The Norc M305 copies "should" be able to digest either or, but still check your headspace if you plan on using 308 hunting ammo regularly.

Stand by for CGN corrections :)
 
Yup! Do some reading. There is a good sticky in the ammo thread about the .223/5.56 debate and just a FYI; SAMMI lists on their site that shooting 5.56 Nato in a .223 chamber is a unsafe combination. (They are the Pro's so no debate nesessary)

The 7.62/.308 difference seems to be less of a issue than the other but opinions still vary. Try some reading and researching online here at CGN and elsewhere ( eg.SAMMI) and you can sift through all the info and usually form a decent opinion of what's what for yourself.
 
it is worth noting that some rifles marked .223 are chambered for 5.56 . i believe some mini 14 were 5.56 and the tavor is 5.56 and marked as .223 .please correct me if i am wrong.
 
You should Wikipedia .223 , 5.56 and .308 , 7.62 x51. Great info and you can compare the writeups. I contacted Ruger a while ago and basically all their firearms are .223, 5.56 and .308, 7.62x51 compatible... So safe to use with any commercial ammo including surplus.
 
As others have mentioned, there are very subtle differences in some of the angles.

A general (but not always) rule is that if you have a 5.56 rifle you are safe to shoot 5.56 and 223 cartridges, but if you have a 223 rifle you should stick to 223 and not use 5.56 ammo.

There is also a rare chambering called 223 Wylde that splits the difference on all the dimensions, and can also fire both.
 
lol I put over 1000 rounds of old US 5.56mm M855 through my old Savage Stevens 200 in .223 Rem. not a single issue.
This is THE biggest non issue panic subject related to firearms since the internet was invented.
Fire on!!
 
buzzmagoo said:
In efect the rifle that I am looking at is a Ruger mini 14 target model. Ruger expressly states 223 only for this model,but the ranch model will except ether 223 or 5.56.:HFU:
Click to expand...

I'm a big fan of the Benelli MR1 model without a pistol grip. It does everything better than a Mini 14 (except price, but better costs money).

BenelliMR1_zpsd3a412d0.jpg
 
farmer47 said:
it is worth noting that some rifles marked .223 are chambered for 5.56 . i believe some mini 14 were 5.56 and the tavor is 5.56 and marked as .223 .please correct me if i am wrong.
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Farmer47 is correct. I have a LMT CQB Ar15. The barrel is stamped 223. I contacted LMT and they said some of their barrels had to be stamped 223 instead of 556 so they could be exported to Canada. LMT assured me I could use 223 or 556 in their rifles. If in doubt check with the manufacturer.
 
I ran 5.56 in a 223 stamped gun. Asked around everyone said it would be okay don't worry gun shop told me it was there idea.Went to clean my gun after 150rounds and found the bolt cracked and fragmented. Not gonna do that again but I do wish my gun was stamped 5.56.if it's not stamped don't do it.
 
Petamocto said:
I'm a big fan of the Benelli MR1 model without a pistol grip. It does everything better than a Mini 14 (except price, but better costs money).

BenelliMR1_zpsd3a412d0.jpg
Click to expand...

Speaking of the MR1, you read my mind I was just going to bring it up.... I bought one last summer and absolutely love it! I am reading online that it can shoot 5.56 as well but I am afraid to chance it as the barrel is marked .223 and it cost me a fair bit. Does anyone know for sure if the MR1 was chambered for both because the local store has a good deal on crates of 5.56 that are tempting me.
 
SAAMI, and North Americans in general, are the only ones who particularly differentiate between the two.

The rest of the world considers the differences to be within normal manufacturing variances and tolerances. In countries that legislate against arms capable of firing military cartridges, they specifically link the two cartridges.

Historically, the difference was for marketing purposes. .223 Remington was marketed to the civilian population as a varminting/ranch cartridge, but they wanted to avoid the association as a small game round when used as a military cartridge (the origin of calling the M16 a "Poodle Shooter" stems from the civvy variant of the cartridge being used to hunt prairie dogs and coyotes).
 
TrashCan said:
Farmer47 is correct. I have a LMT CQB Ar15. The barrel is stamped 223. I contacted LMT and they said some of their barrels had to be stamped 223 instead of 556 so they could be exported to Canada. LMT assured me I could use 223 or 556 in their rifles. If in doubt check with the manufacturer.
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Same thing with the HK MR223. Actually chambered for 556.
 
Canadian_Zuk said:
.308/7.62 is the opposite of .223/5.56. Commercial 308 hunting ammo will be hotter than 7.62x51 Nato ammo. 308 is 60,000psi while 7.62 Nato is 50,000psi, although they measure the pressure differently (copper crush washer vs pressure transducer). The head space is also different between the two along with internal case capacity (7.62 has thicker brass meaning less internal volume). 7.62 Nato can be safely fired from any 308 chamber. If using 308 in a 7.62 Nato gun, make sure you check the headspace first. Further, the pressure curve for 308 may not agree with the gas system on some semi Autos like the M1, this can cause anything from accelerated wear of the moving parts to failure to cycle properly or even catastrophic failure of the firearm in extreme cases. The Norc M305 copies "should" be able to digest either or, but still check your headspace if you plan on using 308 hunting ammo regularly.

Stand by for CGN corrections :)
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The bigger issue for 308/762 is headspacing.

If you want to make absolutely sure you are safe to run 762 in a 308, check the following:

The bolt should close correctly on a 7.62mm Go Gauge of 1.6355", should not close on a 7.62 No Go Gauge of 1.6375" or the .308 Field Reject Gauge of 1.638".

The issue is that a rifle could be in spec using 308 gauges, or 7.62 gauges, but be out of spec for the other cartridge.

308 Gauges:
  • 1.630" GO
  • 1.634" NO GO
  • 1.638" FIELD REJECT

7.62 Gauges:
  • 1.6355" GO
  • 1.6375" NO GO
  • 1.6455" FIELD REJECT
 
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