This seems like a question that should have been addressed in the FAQ section, but I could not find it addressed.

I have just completed my 1st AR build and have caught the bug.  This process was so damn liberating (too corney?) and exciting for me.  I am already trying to secure my 2nd 80% lower to complete.

I now need to buy some AMMO to shoot though my creation.  I intend to buy 4,000 rounds brass case before 12/31 as California has entered Gun-magedon (Or at least expanded its Gun-Magedon).  Plus I see this as investing in semi-precious metals, which one day could be more valuable than today.  I do live in California, so its not paranoia if they are out to get you.

In spending a few hours reading through the posts under the Ammo section it appears most of y'all are using the .223 and consensus is that Wolf Gold, .223, FMJ, 55 Grain @ around $300 per case is a good value.  

My question is that since my chamber is 5.56 with a 1:7 twist why would I want to shoot .223?  Is it just that .223 is less expensive?  What are the practical attributes to buying 4,000 rnds of .223 vs buying 4,000 nds 5.56?

Would sighting in this new rifle with 5.56 be more efficient/effective than .223?

If you have a 5.56 chamber what is your "go-to" round: 5.56 or .223?

What would be your strategy if you were looking to stockpile 4,000 rounds before 12/31 and you had my setup?  (Brand, Caliber, Grain, Case, Price)?

Thanks, I appreciate the resources this forum offers!

5.56 will shoot .223
.223 will not shoot 5.56, unless its a .223 wylde

I should have stated that I understand that I have the choice to shoot either .223 or 5.56.  The relationship is not the same if I was chambered .223.

Just wondering why everyone does not elect to shoot 5.56 if they have their rifle chambered to fire 5.56?

Shoot whats available and cheaper . I shoot .223 mostly, its most readily available around here. I stockpile 5.56. U understand the 5.56 chamber situation, so I will not bore you with that again.

even though Wolf Gold is labeled at .223, it's velocity is pretty damn close to 5.56 levels and it's been shown to fragment very similarly to M193.  that, and it being a good deal are why it's so popular.



very often .223 loads will be more accurate than the same bullet in a 5.56 version.  GECO is a good example of this.  Their .223 load is noticeably more accurate than their 5.56 NATO load which uses the same bullet.

If your barrel is 223 wylde or 556 then don't worry about it, shoot away with whatever

223 is cheaper, generally more accurate, and easier to find than 5.56.  There is really no reason to fire 5.56, ever - the few extra FPS doesn't buy you anything at all.  IMHO, YMMV, of course.

agreed.

However, shoot whatever you want in it. 5.56, .223, heavy, light, etc, it will all shoot fine from your AR.

Thanks ALL for your input.  This is where I am at in the learning curve.

ammunitionstore.com has 223 5.56x45 Ammo 55gr FMJ Wolf Gold Brass Case for USD$.32 per round (Delivery and all applicable taxes).

This seem like a good enough price to "pull the trigger" to you?

Thanks

Yeah, same at SGammo if you buy a 1K case. Haven't seen it any cheaper.

Short Answer, it really depends on the specific barrel.
TBH, either 223 or 5.56 can be very accurate.
Usually 5.56mm 55gr XM193 and similar clones are not accurate, but the Geco 55gr 5.56 is the most accurate 'cheap' ammo I've ever tried.

From my experience, using both 5.56 and 223 ammo that I've found to be accurate in multiple of my rifles:

KAC SR15 Mod1, 16" CL CHF LW barrel, 5.56 chamber
-CBC 77gr OTM 5.56mm (~1.1 MOA 10rd group)
-Geco 55gr FMJ 5.56mm (~1.3 MOA 10rd group)
-AE 50gr 'VT' .223 (~1.2 MOA 10rd group)

KAC SR15 Mod1 LPR, 18" SS SPR barrel, 5.56 chamber
-CBC 77gr OTM 5.56mm (~0.7 MOA 10rd group)
-AE 50gr 'VT' .223 (~0.9 MOA 10rd group)

Colt 6921, 14.5" CL Gov Barrel, 5.56 chamber
-CBC 77gr OTM 5.56mm (~1.3 MOA 10rd group)
-AE 50gr 'VT' .223 (~0.9 MOA 10rd group)

Here for the knowledge.   I got a DD M4A1 a few months back.   I am currently overseas and plan on stocking up while I am making the cash over here.  I bought 1k of the PMC .233 while I was at home and only had time to shoot about 300 rounds.  My old man has been shooting it and probably put another 200 through it.  I have been reading these boards for only about a month now, but I am in the same situation as the original poster.  So far I like the PMC, but was confused if I should buy 5.56 or .223.   I was reading that if your barrel is chambered in 5.56, you will lose pressure firing a .223, which makes sense I guess.  But from the responses, I guess the loss does not outweigh the performance.   Am I on the right track?   Thanks.

The ammo sold as 5.56X45 (62,350 PSI) whether 62 grain or 55 grain is loaded to higher pressure than 223 Remington (55,000 PSI).  More pressure equals greater projectile velocity.  The chamber throat has more free bore in 5.56 chambers compared to 223 Remington chamber.  It is safe to shoot 223 Remington ammo in a 5.56 AR-15 but generally the velocity will be lower than ammo loaded to 5.56 pressures.  In my araea 223 ammo 55 grain FMJ is generally about .50-$1 cheaper for 20 rounds compared to 5.56X45 55 grain FMJ 20 round box.

As several have said it comes down to cost. If you don't plan on reloading and want to sell the brass to someone else you might want to find out what they prefer.

This, .223 is definitely more accurate, but a lot of people seem to be hung up on 5.56 so it's easier to sell if you ever need to.

Similar to JayC's comment, I would have to say 223 is generally more accurate, but not always.
The short answer is... it really depends on the particular barrel, a lot of factors have to be considered.

From my experience, the 5.56 did better in my 1:7 twist guns like my SR15 Mod1 & LPR, Colt 6921 14.5", and PSA premium.
The two brand/type they all like is the CBC 77gr OTM, and GECO 55gr 5.56 ammo

As for the 223 spec ammo...
My Steyr Aug w/ 1:9 twist barrel, and my Colt SP1 1:12 twist usually prefer 223 spec.

The only 223 load all of my rifles really like is the AE 50gr 'Varmint'.