I’m still researching my AR build. 223 or 556?
- 223
- 556
- Both
0 voters
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55 grain 5.56
Or go with a 2.23 wylde barrel depending what your budget is
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Doesn’t the 556 shoot both regardless? I’m pretty new to ARs myself, I’m under the impression that the 5.56 ARs fire both.
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You are correct the 556 will fire and operate the 226, but not the other away around. Have a great time.
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556/223 Correction, please !!! 556 and 223
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Yes Mr Spence, the AR 15 that shoots the 556 and the 223. On the barrel and your owner guide will tell yo.
If that barrel is marked 556, you have the ability to use the 223. I have a Sig Sauer and a Springfield
AR15s; 5.56mm.
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That’s 100% correct. I only suggest the 223 wylde because tho the 556 can handle both the 223 wylde was specifically designed to handle both. That’s all. Hence depending on the budget and goal of a build it could be a viable option.
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What do you think of the Sig AR, @William_H? Does it shoot as smoothly as their pistols?
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The Sig Sauer AR15 M400, is a fanatic rifle (556/223). It is able to carry several attachment
of your choosing. Fixed front sights, P Rail (mid fore arm) , rear sights. I enjoy it more than
the Springfield Saint. (That forearm 8.5 " was changed) The weight can get heavy some.
Shoots very well and on target right out of the box.
Thank you
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Thanks for the feedback! To build or to buy a Sig… decisions, decisions. 
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Sig Sauer has several options available and they can fit any bodies likes or dislikes.
That certain model is like what the SWAT TEAMS use. Your choice, ask SIG SAUER.
FANTASIC .
Thank You
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The thing with the AR platform is that it’s so versatile and you can literally change almost every aspect of it. If you decide to buy one do yourself a favor and save everything you change on it. As you gain experience with it and change it to fit your needs and wants better you’ll have almost enough parts to build half of another rifle.
I bought my first one and built my second one from everything I learned from the first. You have a huge resource with working with USCCA and having input from experienced co workers. (Tho that is a double edged sword) either way you go you’ll be hooked and enjoy it
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@Dawn It just so happens…
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That’s part of my hesitation to buy my first one! That and I want the new Sig XCompact. I’m hooked on my handguns. It’s not a question if I’ll get hooked on ARs, it’s a question of when… 
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My 2 cents, go 300 Blackout. Here in leveraging run Illinois, we can’t deer hunt with rifles. But, through a loophole, we can use an single shot, AR pistol in 300 BLK. Single shot, pistol, and the overall case length falls in the parameters for bottle neck cartridges. 300 is a very versatile caliber.
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I’ll be honest I dont know a lot about about the Sig, but you can take everything you like about it and build one just like it. It just won’t say sig on the side of it.
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That’s why I went with .223 Wylde for my first since I wanted the best of both worlds between .223 rem and 5.56 nato. I then built a 5.56 for my wife, then I finished off with a .300 blackout.
We went to the range this weekend and I decided I’m getting a CMMG .22LR conversion kit. You replace the bolt carrier group with this and use the included magazines in your standard lower and 5.56 upper.
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556, it’s a higher pressure round that also supports 223. Given the lower pressure of a 223 rifle it doesn’t safely support 556
I think of 556 as military grade and 223 is consumer grade. Both great, but if given the choice go with 556 
223 came first and the military wanted a bit more pressure/power and hence 556 was created.
I’ve been doing the same research as I’m working out the specs for my first AR-15 as well.
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@Dawn I voted both as being a down in the weds rifle guy I understand more than a little bit about chambers and such. The 5.56 NATO chamber is a touch “generous” so that it works in the water, mud, dirt etc. while the .223 Rem chamber is cut like any other precision round (ie. no wiggle room). The Wylde chamber is essentially cut like a precision .223 all the way up to the end of the brass and then things change. The secret to the Wylde Chamber is an increased Freebore and extended Neck length, the 30* leade angle also helps.
Definitions:
Freebore is the diameter of the chamber after the end of the neck. In this case .2240" vs .2230" and the length of the Freebore is .062".
Extended Neck: The length of a 5.56/223 neck chamber is .203" and the Wylde is .223". This is important if you re-load in that you can have more neck on your brass before it gets crimped by the chamber. In regular situations if the cartridge is over pressure it gives more volume in that magic moment when the boolet leaves the brass and slams into the leade.
Leade: is the angle cut into the rifling where the boolet meets the steel. 30* is a very forgiving leade.
So why are all these little changes important? It’s all about pressure. Let’s say you get your .223 chamber HOT through firing and end up leaving a round in the chamber while you chat for a minute or two. When you get back on the gun that chamber has been trying it’s best to get the surplus 5.56 round you chambered to the same temperature it is (Heat Transfer) Brass is more than willing to do this. As we know from 3rd grade earth science heat contracts and cold expands. Now your chamber is smaller and the brass is smaller but the powder inside is the same size because it’s mostly graphite. At best when the round is fired it will land high on the target. Next best is the bolt will tear the rim off the case and blow the magazine out the bottom of the rifle. There are worse things that can happen after that.
Hope that helps clear the mud, that’s as short as I could make it w/o typing for an hour.
Cheers,
Craig6
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My next purchase (Lord willing) is a Bushmaster XM-15 M4A3 Patrolman’s Carbine 223/556. That’s what I like…
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