Lil help

[jworm1420]

getting ready to go purchase my first AR.... had a few questions..... AR caliber .223 I've heard also shoots 5.56????? but I've seen5.56x9mm and by45mm..... also in theory, u can buy a fully assembled upper and fully assembled lower, put together and shoot??????? Any other things i should look for or any pointers would b appreciated .. Thanx everybody!!!!!!!!!!

 

[Stschil]

I'm no AR expert, so take what I say with a grain of salt.

You should be able to mate any complete upper to a complete lower without issues.

The .223/5.56 question. 5.56 is a NATO round and carries higher pressures than the civilian .223. Most AR's these days are chambered for the 5.56 , check the stampings, and shooting .223 will cause you no problems whatsoever.
The opposite is not true. If the barrel is chambered for .223 only, the higher pressured 5.56 NATO can eventually cause catastrophic failure. This can occur with the first round or the 400th. So it's not a good idea.

Also, use the search feature here and look up some of the many AR threads. There is loads of good info there.
I'm sure there will be others along, much more knowledgable than I, who can give more specifics.

Hope this helps

 

[JohnP82]

Like Stschil already stated .223 is good to go in a 5.56 barrel but it is not recommended to shoot 5.56 through a .223 barrel.

Yes most complete uppers should function with most any complete lower. Sometimes you will run into some minor issues that can be worked out.
As long as the complete upper comes with a BCG then yes it is ready to go. Some places say complete upper, but they do not have the BCG.

One other thing to consider, which is more important to some than others is the twist rate of the barrel, i.e. 1:7, 1:8, 1:9 which has to do with how well it stabalizes different weights of bullets. Some of the experts can elaborate more on that topic if you want to know. I understand it, but my explanation would not be as good as some of the other member's.


Any particular manufacturers you are looking at?

 

[chuddly]

I want to clear up the .223/5.56 thing before we move on...they are NOT just different pressures. The 5.56 has a longer throat on the shell casing and thus the reason you DO NOT want to fire one in a gun built for only .223. You can shoot a .223 in a 5.56 gun but you will loose some of the accuracy. This is minimal loss though.

A quick run down on the twist (very quick). The twist rate you are going with should line up with what you are doing with the gun. a 1:9 twist is a good all around gun that shoots light rounds (52gr) up into the medium weight bullets (65 ish). It can shoot the heavier bullets but they are not as stable at that point because they are not spinning fast enough. 1:8 is a pretty rare barrel so no need to mess with that one and it just fits in between the others. The 1:7 twist is good for heavy bullets (80 gr) but can destroy lighter bullets (anything below 55 gr with a light jacket). It literary spins the bullet so fast that it blows it apart when it comes out of the barrel. it does this because when a bullet leaves a 1:7 twist barrel it is turning at about 300,000 rpm. Now you can also get into bullet length and all the fun stuff but we will leave that be for now also.

Also i wanted to note that from what i have read some of the barrels out there are marked 5.56/.223 but are actually only chambered for .223 so a little research on the maker will do you some good.

 

[jworm1420]

thanx for the help everyone. i really appreciate it. il post info n pics when i get it. thanx again for giving me the confidence to make his purchase.