5.7x28 AR upper, why not?

i never was attracted to the pistol caliber carbines unless you were restricted to say a pdw and concealment is key. i still think the 223/5.56 is a better caliber to have around and plenty on the shelf by now plus a wide variety of ammo for it.

The 5.7 X 28 MM cartridge bullet energy fits between the 22 WMR and 22 Hornet when fired from a rifle length barrel. I m not a semi auto fan but should I find a used short bolt action rifle that could be re barreled with a 5.7X28 MM chamber I may get it. Should you find an upper for your AR rifle get it and enjoy.

Instead of asking why not, you may want to ask why.

It's a neat round for its intended purpose and the platform carries a lot of ammo. However, expensive to plink with in my mind and I think ammo in the long term may be a bit of an issue.

One of my regulars had one and would shoot it in some of our carbine matches, but it really ... REALLY ... seemed that the only single thing it did better than a 5.56mm carbine was hold 50 rds. in a convenient and interesting magazine. (That was slower to swap out than a standard 30-rd mag, so a bit of a wash.)

If you were already heavily invested in that round, I could maybe see getting one. Otherwise, naaaaaah.

You'd lose a lot of benefits of the PS90 platform by going with an AR upper. I know it's cheaper to go the upper route, but the main draw of the PS90 is ergonomics, light weight, and (most importantly) the bullpup deisgn. It's extremely compact.

(Not to mention, accurate, but if the AR upper mfg. knows their business on barrels, that'll be a wash).

Since the ergonomics in the upper are going to be the same as the parent platform (AR-15), you really need to compare what you're gaining or losing against an AR upper. You aren't switching weapons platforms, you are converting an existing one.

Ability to shoot a new caliber? Great, *but* it's one that has historically been kind of hard to locate ammo for at times (now is not one of those times, fortunately, I just picked up 1500 rounds of Fiocci last week and got to comparison shop from vendors with it in stock).

Ability to hold more ammo? Great.. but you can do the same thing in a conventional AR with a beta mag. And... (hate to sound like an anti-gunner here), but you have to ask yourself "do I really need the extra X number of rounds?" With the cost of ammo, you're talking about burning $25 per 50 round magazine. That's not cheap. (Same cost as most 223 ammo).

But I reload...! Well, so do I... and the 5.7x28mm is no joy to reload. You have a dramatically reduced projectile selection over a 223 cartridge, a very narrow band of suitable powder burn rates (powder is still hard to find in some areas), etc. I looked for quite a long time before finding projectiles and suitable powder to use last year. On top of that, the cartridge is a persnickety little bugger to reload. Not at all like other rifle rounds.

Now.. if you already have a pistol and simply want to be able to use the same cartridge to reach out to 200 yards, go for it! (It is perfectly capable of remaining very accurate out to 200; I've won sporting rifle matches with a PS90 before. At 300 yards it's dropping like a meteor though, much more difficult to score hits, but still possible)

Ammo availability has been a "long term concern" going on 30 years, now. There are multiple manufacturers and a ton of guns in the caliber, and more sold every day. No, it won't be as common as 223 unless NATO adopts it, but neither are many other popular calibers.

TCB

I could see it in the same role as a .22 Hornet for varmint/predator control in areas that are a bit too populated for the much louder .22 centerfires .223 & up, areas which do not need the range of the larger cartridges but may have shots which are really pushing the limits of rimfire rounds. The Hornet definitely has an edge over the .22 mag and is not a whole lot louder; the 5.7x28 would offer that same low noise with increased performance, plus being able to use an autoloader that conveniently catches it's own brass.

Other than that application, though, I see the 5.7 AR upper as basically useless.

barnbwt said:

Ammo availability has been a "long term concern" going on 30 years, now. There are multiple manufacturers and a ton of guns in the caliber, and more sold every day. No, it won't be as common as 223 unless NATO adopts it, but neither are many other popular calibers.

TCB

Click to expand...

It *would* have been adopted by NATO if H&K hadn't successfully lobbied Germany to block it. The vast majority of countries chose 5.7x28mm over H&K's 4.6mm round.

NATO standardization isn't the begin-and-end-all of any given cartridge. Sure it can go a long way to rapidly making acceptance, world wide. But even without it, the 5.7x28 has gained quite a lot of commercial and government acceptance throughout the world. Enough to keep the production lines running for a very long time (particularly since they can be easily converted from producing 223 to 5.7x28mm or back again).

It's not a mainstream cartridge, but it's on the brink of becoming one (several local stores stock it now).

You won't ever likely see stockpiles of cheap 5.7x28mm surplus hitting the market (at least not in our lifetimes), but still, I don't think finding ammo will be a problem beyond the occasional panic sprees we tend to have in the US...

It's got a lot better shot than 4.6x30 at going mainstream, at least . Given its sensitivity, I don't think I'd even want 40 year old surplus 5.7

TCB

Yes I gotta ask why. 5.56 is cheaper all around.

barnbwt said:

It's got a lot better shot than 4.6x30 at going mainstream, at least . Given its sensitivity, I don't think I'd even want 40 year old surplus 5.7

TCB

Click to expand...

The old white box SS195 "lead free" wasn't shelf stable anyway. The lead-free primers become inert after 7-10 years.

Not sure about the SS197SR, but long term storage hasn't been a concern yet. I've got 10 year old SS197SR that shoots fine still. (Not MUCH of it, but I've earmarked some boxes to hold back and shoot every couple of years just to satisfy my curiosity.)

Yes I gotta ask why. 5.56 is cheaper all around.

Click to expand...

I would agree there's no point, if someone loaded "mouse-fart" 223 such that a small carbine (or SBR) would not make the gods flinch in pain when fired, especially indoors. Just as there is a use for 38spl over 357 in certain scenarios, such is the case for 5.7. A true pistol platform situation makes the need for something less powerful than 223 blantantly obvious, a PDW fairly obvious, and an AR upper even less obvious --the need is still there though, if you intend the carbine for lesser roles than to which 223 is suited. And don't forget that you do get a very impressive mag capacity without any protrusions besides the pistol grip (it just occurred to me that an ARES SCR somehow modded to use a 57 upper and SBR'd would be pretty dang slick and handy)

What I'd like even better would be for that dude on barfcom to manufacture and market his direct impingement AR modification to 5.7 --that'd be something neat, for sure, and a boon to reloaders of the round. Apparently it has enough oomph to rock a pistol-length gas system (with 16" barrel) with a lightweight buffer & spring.

TCB

Barn raises an interesting point that hasn't been raised before.

I keep the PS90 ready to go for wife & kids for home defense, since it's so easy to handle and fast / intuitive to operate.

Firing a 223 indoors is a very unpleasant experience when you don't have time to put on ears.

Firing a 5.7x28 is still a shock, but much less of one. Also risk of over penetration in apartments/close together housing is much less of a concern. (We have 5 kids, 3 dogs, 4 cats, so over penetration is a serious concern here at my place.)

I think the 5.7 rounds is probably the best thing going right now.

Small, lightweight, effective to 200 yards in rifles AND handguns, devastating wound ballistics (think 5.56 fragmentation), light recoil, flat shooting, can easily defeat light body armor, it's pretty much a complete package.

I say go for it.

[QUOTE='mavracer"]5.56 is cheaper all around.[/QUOTE]

Only if you buy the cheapest garbage .223/5.56, and then only by a few cents. 50 Rounds of bottom of the barrel .223/5.56 usually runs around $22-$24. Twice that for premium ammunition. I pay $23 for AE 5.7 and $27 for the SS197SR So, even in the best case scenario you really aren't saving much money at all.

I always wonder when people bring up the price of 5.7... have 1911s gone out of style again? Because .45acp and 5.7 are pretty much the exact same price.. but no one seems to complain about .45s being too much.

As for why? OP states it's going to be a range toy. When has any true shooter every turned away from a range toy because it's an oddity? Heck, I think most of us like it when people cluster around to see the weird gun your brought.

Why for real use? Because you get less noise and recoil than a 5.56 with the same familiar controls on the AR lower. Bonus points for not having to bounce brass off walls, people and other things. Mag swaps are a little slower than a standard AR (faster with the Gen 2 uppers), but seriously... if you find yourself in a home defense situation where you've gone through 50 and need more... that's a bad bad night.

Here's my SBR Gen 2:



I've taken a couple of small hogs and a coyote on the ranch with it. Did just fine. Know the guns limits and it will do just fine. If you need a magnified optic to see the target, you probably need another gun to shoot it. If it's going to be up close and personal, no problem.

Only if you buy the cheapest garbage .223/5.56, and then only by a few cents. 50 Rounds of bottom of the barrel .223/5.56 usually runs around $22-$24. Twice that for premium ammunition. I pay $23 for AE 5.7 and $27 for the SS197SR So, even in the best case scenario you really aren't saving much money at all.

Click to expand...

Well since I saved $200 on the upper and my mags cost 1/4 as much I'd say it's gonna take a long time for your ammo non savings to catch up.

And if 5.56 recoil bothers you................................ damn THR rules.

Only if you buy the cheapest garbage .223/5.56, and then only by a few cents. 50 Rounds of bottom of the barrel .223/5.56 usually runs around $22-$24

Click to expand...

I'd hardly call 2 moa ammo garbage, I was in Academy this morning and they had Monarch steel cased ammo for $6/20, that is $15/50, your rationalization is using bad data.

I'm not against the 5.7, in fact I have the AR57 upper and a PS90, but ammo cost is definitely a negative for it. I picked up several thousand rounds way back when Sportsman's guide was selling it for ~$18/50 which was still well above non-premium 5.56 back then.

mavracer said:

Well since I saved $200 on the upper...

Click to expand...

Ah well, I was going to put this 5.56 upper on my SBR lower, but it's $1,100... So I saved $500 going with the 5.7

See how that works?

Now, were we talking ammo costs or complete weapon system costs... Because I've never seen a 5.7 system for $2K+, but I can find that in 5.56 all day. So, let's not try to play the "5.7 weapons systems are more expensive than 5.56 weapon systems" game.

mavracer said:

And if 5.56 recoil bothers you................................ damn THR rules.

Click to expand...

When out of facts to argue, Ad Hominem is always the best choice.

To help you along here, when I'm on foot in the heavy cedars, I use a Marlin 1895G loaded with 405gr bullets on top of 48gr of RL7. So no, 5.56 recoil doesn't bother me.

But my wife, who has access to the same firearms and sleeps in the same bed is 4'9".

I'd hardly call 2 moa ammo garbage, I was in Academy this morning and they had Monarch steel cased ammo for $6/20, that is $15/50, your rationalization is using bad data.

Click to expand...

You know that Monarch is just Privi (brass) or Barnul (steel) brand ammo manufactured for sole distribution at Academy locations right?

I wouldn't hold it up as anything other than what it is, cheap com-bloc import.

I wouldn't hold it up as anything other than what it is, cheap com-bloc import.

Click to expand...

I know, but it generally shoots 2moa in my ARs which is pretty much the accuracy spec of what gets issued to the troops.

I shoot lots of it at steel plates, I liked it even better back when it was $3/20

ClickClickD'oh said:

To help you along here, when I'm on foot in the heavy cedars, I use a Marlin 1895G loaded with 405gr bullets on top of 48gr of RL7. So no, 5.56 recoil doesn't bother me.

But my wife, who has access to the same firearms and sleeps in the same bed is 4'9".

Click to expand...

Agreed. My wife has serious trouble with 9mm recoil, even from a full size gun that dampens it down some, she's just too small. She carries a 380 ACP in her purse, about the most recoil she can handle. I've got a 38 special tucked away in the kitchen for her with mellow loads that she's good with too. (Figure bad guy isn't going to really care if he's hit at 800 fps vs 950fps... him getting hit in the first place is more important at the moment..)

223 recoil isn't bad *but* the noise when fired indoors is absolutely horrid. Muzzle flash can be eliminated with a Smith Vortex flash suppressor, but still, it's like hitting yourself with the sonic part of a flashbang. (M-8 stun grenade is ~170 decibels, a 20" AR is 160-165db, and it gets MUCH louder from a 16" or 14.5" tube.)

Conversely, a 10.5" PS90 is 158db, and it gets MUCH quieter as you move to the standard 16" barrel.

16" PS90 is still not hearing safe, but it's at least well below the threshhold of a damn flashbang grenade going off less than 2 feet in front of your face in an enclosed space. Which is essentially what your'e doing when you shoot an AR15 223 indoors.

I don't need the extra power of devastation the P90 give the 5.7 as I don't plan on ever travelling to a far off planet to mow down ranks of Jaffa. It's performance from an AR57 upper is plenty and I'd like to have one for no other reason than it sounds like a lot of fun. I wish I'd bought one when it was on sale for under $500. The 5.7 is a practical round- more so than the 22 mag.

I wonder if Ruger can be convinced to chamber a 77/22 style rifle in 5.7?