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View Full Version : 5.7x28 uppers for AR-15


CraigC
November 5, 2009, 12:20 AM
I'm mostly into traditional guns but on occasion get a little black rifle fever. Been wanting an AR for quite some time and as of late I've been thinking about getting one with a 5.7 upper. The cartridge interests me and I think I'd get a lot of utility out of it. Seems to fall somewhere between the .22Mag and the .22Hornet ballistically. The 50rd magazines are a nice feature as well as using a hogged-out AR magazine as a brass catcher. While factory ammo is $21 or more per 50 it looks like I can reload it for less than half that. I figure the 40gr V-Max would be a good coyote load. Thoughts???

http://www.57center.com/18.html?sm=68015

Latex Ducky
November 5, 2009, 01:12 AM
Are those compatible with the FN PS90 Mags? Why not just stay with the .223? What sets the 5.7 apart for you?

You can buy brass catchers that attach to the side of an AR but the 50rd mag in a compact space is a plus.

How much is the upper? I didn't know this existed!

Magnum Wheel Man
November 5, 2009, 12:08 PM
CRAIG... I'm not an AR kind a guy myself, & because I'm a reloader, I shy away from the semi autos that throw those golden gems all over, requiring this old dude to have to get down on the ground to pick them up... for my old AR ( in 223 ) I had a brass catcher, but found it awkward & cumbersome...

the 5.7 conversion is much more practical & interesting, almost makes me wish I'd kept my old AR, feeding from the top, & throwing brass out the bottom, like the Calicos ( that feature always interested me there too )

the "problem" with reloading the 5.7 ( it is the most difficult of the 40 or so calibers I reload ), is...

1st, the guns firing the cartridge, are all blow back ( including the AR upper... no locking bolt ), & the pressure is high enough, that the shoulder blows forward between 1/16" & 1/8" & must be moved back each time they are sized... to help the blow back actions deal with the higher pressure cartridge, the brass cases are laquered, which gives some sizing issues all their own... I've gotten pretty good at loading them now, after 1000 rounds or so, ( BTW I even had to alter my early dies, as they weren't short enough to properly size the cases... new dies are likely better ), I had to "shop" for a tight enough shell holder, the 1st 2 I bought, were too loose, & caused me problems with the tight sizing cases... I had to get a file trim die, as the cases stretch so much, which brings me to case life... I don't expect more than 3-5 reloads per case, & get a throw away rate of about 5% every time I go through a batch of once fired cases, twice fired only gets worse... I've had once fired cases pull the necks off in resizing, meaning I need to disassemble my die & figure out how to get the neck out of the die... probably had a couple other issues, but it's been a while now since I've loaded them...

... I was able to buy a 1000 once fired cases, so that was good, but at this point, new cases are not available... though Starline is rumoured to be "going" to start making them...

interesting good points... the twist rate on the FN guns is fast enough, that you can pretty much shoot normal 223 bullets, as well as the ultra light weight aluminum cored bullets that are the norm with the 5.7 X 28... if the AR barrels are the same, that would be a good thing

... all the difficulties I encountered, fueled my expiriments with the fast twist 22 Hornet... I find that by going to a 1 in 9 twist in the Hornet, I can do most anything the 5.7 X 28 can do ( except cycle through a semi auto :o )

BTW... I have a 5.7 X 28 Contender barrel, in which, the shoulders do not move back, which should greatly increase my case life, & which also greatly simplify's my reloading... if the AR conversions used a locked bolt like they do for the other calibers, I think I'd have to get one myself...

if you want, a search might turn up my thread in the reloading section on reloading the 5.7...

rjrivero
November 5, 2009, 12:57 PM
CRAIG... I'm not an AR kind a guy myself, & because I'm a reloader, I shy away from the semi autos that throw those golden gems all over, requiring this old dude to have to get down on the ground to pick them up... for my old AR ( in 223 ) I had a brass catcher, but found it awkward & cumbersome...

Stick with .223 and use one of these. Link Here (http://www.hitfactorshooting.com/product.sc?productId=64&categoryId=18).

CraigC
November 8, 2009, 03:45 PM
Thanks for the info MWM, that's the sort of thing I was looking for. I'm gonna chew on it for a while. I 'may' decide to go ahead and get one and just run factory ammo through it. It's not too awful bad at $21/50, although I figured I could reload it for well under half that. The difficulties you describe make me think twice about fooling with reloading for it. I do think it would be cool to have a compact boltgun in the chambering. I think it's a neat little cartridge, although it does nothing you can't do better with a K-Hornet.

The .223 is a fine cartridge. I'm considering it but I don't think it's really what I'm looking for at the moment. If I was gonna go with a traditional upper, it would probably be a 6.8SPC.