Different uppers for AR-15 ... confusion

[Jeff Thomas]

I know one of the great attributes of AR-15's / M-16's is their adaptability, especially by using different uppers. I'm still left with some confusion. [Most of my questions relate to Bushmasters, but I assume the answers would apply to all AR's?]

1. Besides the normal .223 configuration, I gather the normal alternatives are 7.62 x 39 and 9mm. If you use one of these uppers:
a. Don't you need special magazines? And, if so, where do you buy them - I don't remember seeing them advertised for sale.
b. And, if you use special magazines, then I assume you need an adaptor for the magazine to fit properly in the lower?
c. What are some of the reasons you might want a 7.62 or 9mm?

2. Back to the .223 version, is it legal to possess a 'pre-ban' upper for use on a 'post-ban' lower, in the hope that the idiotic 'assault weapons' ban expires in 2004? [I'm assuming it is illegal to attach it to a post-ban lower at this time.]

3. If you were buying a .223 upper, which would you choose for your AR, assuming you want the best all-around rifle for defense, hunting, plinking, etc.? I gather the vortex flash hider is considered the best, but what about length and any other features?

4. What is the smartest way to buy an upper? I note the prices in Bushmaster's catalog are pretty steep. Is it smarter to buy less than the entire upper (i.e. just the barrel, or ...) ?

Thanks. Regards from AZ

 

[dZ]

7.62 are expensive mags although some claim you can load 7.62 x 39 in a straight 20 rounder

you also loose the wounding potential of 5.56

9mm is a carbine load & uses stick mags & a mag well adaptor

why? cause ya can
also some ranges are pistol ammo only

i would not have a post ban lower & a preban upper in the same house unless there was a preban lower there too.

the real vortex is a flash hider & is a preban goodie. the post ban compensators must be attached either with set screws over a plain barrel end, or silver soldered onto a threaded end. If you ever want to add a free floated grip, you will need to remove the front sightbase & will find the soldered compensator in the way.

you must also have a 16 inch barrel and need a soldered on extension on a M4 barrel

Bushmaster is quality and worth the price
you get a NATO chamber & a chromelined bore

I like the 20 inch barrel because of the full sized sight length and you get a bit more FPS than a 16

for CQB the 16 inch is handy, but the last time i cleared my house i used a hoover upright.


HTH
dZ

 

[4V50 Gary]

The beauty of the AR is that it is a weapon system. You can begin your day with a short barrel carbine (M4), make it into a sniper rifle by putting a free floated heavy barrel scoped upper and a cheekpiece by noon, and by evening, insert mag well fillers and a 9mm upper and have a pistol caliber carbine.

Whatever caliber you choose, you'll probably need a special magazine. Pistol caliber mags are unique but some firms, like Oly will adapt a Sten mag for it. The .223 is different from the 7.62 x 39mm, though in some instances, you can get the .223 to work (but don't count on it). The newest system was mentioned by Coinneach and is a single shot 50 caliber upper. As it is single shot, the bolt is screwed into the (modified M2 MG) barrel and thus, when fired from the bipod, the recoil is very gentle.

Concerning mating a preban upper with a postban lower, don't! This is an instant ticket to Club Fed. You have to have a pre-ban lower around to do this legally.

From what I've read, I consider the 16" heavy barrel to be amongst the best for all around use. It won't take you out to 800 yards like the 20 HBAR, but you won't be shooting that distance with a 16". It's handy for self defense or varmint hunting. With 16", you won't get hung up in the woods like you could with a 20".

Finally, since I have the tools, I would buy the parts and assemble them myself. If you go to http://www.ar15.com, you'll find out where you can get good parts. I try to stick with Bushmaster and DPMS. Armalite is good, but I've never dealt with them. When you build your own upper, you not only know the system better, but can trouble shoot it since you're intimacy is greater. You can also save some ducats that way too.

 

[Nukem]

You can go with a .300 Whisper upper and get a .30 cal that will fit and feed in the .223 mag (it's based on the .223 case)

Just a thought.
It would call for a brass catcher for sure since you have to form it yourself.