Ok, I haven't got a clue. 223 or 5.56

[Infidel]

My grandson has come into the ownership of an AR-15. Anyhow, what is the difference between the .223 and a 5.56? Someone asked me this the other day and I had no answer. He said he could chamber a .223 in his gun, but couldn't chamber a 5.56. The only explanation I could come up with was shoulder angle differences. I don't have any experience with the two cartridges, I have the evil 7.62X39's. Any help would be appreciated. :veryconfu

[Moonie]

The only difference really is the freebore in the chamber, the cartridges are externally exactly the same. You can shoot .223 in a 5.56 chamber but you should not shoot 5.56 in a .223 chamber as excessive pressure could result. At least that is my understanding having owned both a .223 rifle and now an AR-15 in 5.56.

[Infidel]

Not sure I understand. What is freebore? Is that the throating to the rifling? Or is it that the 223 isn't built as heavy as the 5.56?

[ole 5 hole group]

Some people use the term freebore as a catch-all phrase to mean a lengthened chamber where the bullet jumps a short distance before contacting the rifling. Think of it as a section of barrel ahead of the cartridge case being reamed roughly .001" over actual bullet diameter for approximately 3/8"to 1/2".

The 5.56 cartridge is normally loaded to a higher pressure, as the 223 is rated at 55,000psi while the 5.56 is rated at 62,000psi or 65,000psi. So, the 5.56 fired from a freebore chamber handles the pressure very well but without that freebore in a 223 chamber the pressure will be up there a little which causes a little more wear & tear on the bolt carrier group.


The 223 & 5.56 cartridge has the same dimensions, so there's no problem there mixing the brass when reloading but the military ball is a hot rod in a 223 chamber.

[joesig]

69336

[dkf]

Here are a couple articles that may interest you.

http://www.luckygunner.com/labs/5-56-vs-223/
http://www.gundigest.com/223-vs-5-56

For an AR I will only buy with a 5.56 or .223 wylde chamber.

[Michaelcfffg]

So Infidel, how is your grandson's rifle marked, .223 or 5.56 mm. After reading the very good second article provided by dkf, it sounds like one should only purchase a rifle chambered for 5.56 mm, and then have it checked to be sure that it's within spec for that, cause it may not be. Very interesting stuff!

[bangerjim]

How about if you are reloading 5.56 stamped once-fired brass to a standard .223 Rem load per the standard load data???

Is that OK? The pressure should be OK then..... I would think?

The brass is marketed as 223/5.56 once-fired.

The rifle is sold as 223 Rem. It is NOT an AR-15, but a standard long gun - bolt action.

Kindly advise your thoughts!

[bob208]

they are one and the same. same as .308-7.62 nato. i guess next some one will say the .30-06 is not the .30-06. yes i know about the loads for the m1.

[Doc Highwall]

Bangerjim, the case that you use is not as important as the reloading data that you use. As long as you use the recommended powder charges and over all length you are good to go with jacketed bullets.

With our cast bullets and lighter loads, bullet fit will be the main issue.

[bangerjim]

THANKS! I thought the load was the critical part! I always start off light and end up at about the middle or slightly higher with my loads. Have never "gone off the deep end" with max loads. I value my arms and "arms" too much!

This site has always been my go-to place for reading about loadin', lubin', and castin'. I signed up last month to be able to join in and ask questions.

Lots-a-fun! 8-)

[BUSHMASTER]

you are wright on the money since ive joined i had more help and advice any one reading this knows the importance of good intel
i get that her im really enjoying being a member of cast boolits

[W.R.Buchanan]

Most semi auto guns are now being chambered in 5.56. My Mini 14, Bushmaster AR and Kel-Tec SU16CA are all marked that way. All were made in the last 10 years.

Bolt guns, other than those specifically made for tactical uses, (IE: Mossberg MVP) were generally chambered in .223 Rem.

The gun will be marked which ever way it is chambered. This was a problem in guns manufactured earlier. However most guns manufactured recently have the 5.56 chamber so they don't cause problems. This is especially helpful nowadays since there is a large amount of Surplus Military Ammo being shot.

My personal opinion is that the .223 Remington chamber should be eliminated altogether. There is only a minute difference in the chamber but that minute difference can cause problems. If all chambers for these cartridges were just done in 5.56 then the problem would go away.

There is little difference in the inherent accuracy of the .223 over the 5.56 even in a varmint type rifle so what's the point. Slower barrel twists for use with lighter varmint type bullets would not stabilize heavier bullets but really you can do anything to a prairie dog with a 55 gr bullet that you can do with a 40,45,or 50 gr bullet and a 1 in 9" twist works fine for 55 gr to 68gr.

Once again,,, what's the point?

[GabbyM]

Never had an issue shooting M193 ball from my 223 rifles. Bolt or AR type. However with today’s popular heavy bullet hand loads. I’d not want to try out an 80 grain Sierra loaded to the rifling on a 5.56mm NATO chamber in a 223 Rem chamber. Closing the bolt or dropping the action on an AR would probably just deep seat the bullet then you’d have a high pressure round ready to go.

[GabbyM]

Most semi auto guns are now being chambered in 5.56. My Mini 14, Bushmaster AR and Kel-Tec SU16CA are all marked that way. All were made in the last 10 years.

Bolt guns, other than those specifically made for tactical uses, (IE: Mossberg MVP) were generally chambered in .223 Rem.

The gun will be marked which ever way it is chambered. This was a problem in guns manufactured earlier. However most guns manufactured recently have the 5.56 chamber so they don't cause problems. This is especially helpful nowadays since there is a large amount of Surplus Military Ammo being shot.

My personal opinion is that the .223 Remington chamber should be eliminated altogether. There is only a minute difference in the chamber but that minute difference can cause problems. If all chambers for these cartridges were just done in 5.56 then the problem would go away.

There is little difference in the inherent accuracy of the .223 over the 5.56 even in a varmint type rifle so what's the point. Slower barrel twists for use with lighter varmint type bullets would not stabilize heavier bullets but really you can do anything to a prairie dog with a 55 gr bullet that you can do with a 40,45,or 50 gr bullet and a 1 in 9" twist works fine for 55 gr to 68gr.

Once again,,, what's the point?

55 gr bullets really fall short from 223 on prairie dogs. To heavy of a construction for one thing but the wind and time to target makes hits at a quarter mile much harder. 50 gain Sierra Blitz-King is my favorite. Hornady has a new 53gr V-Max but I've not tried it. I prefer the 223 REM chamber even in my AR's. If you reload anyways you set your own clearance with your die adjustment. So why put up with cases blown out and often lopsided. Also getting a long nosed 50gr bullet to shoot good backed off from rifling is about a no go proposition. If you want to shoot heavy bullets like 77 and 80's get a Wylde chamber. Long NATO throat but tighter body dimensions. For prairie dogs the heavy bullets take way to long to get there. Little buggers move on you. In an M-16 rifle for battle I'd stick with the military 5.56mm chamber.