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  #1  
Old April 1st, 2007, 12:17 AM
ddavis ddavis is offline
Daniel Davis
 
Join Date: Oct 2006
Posts: 48
FN fiveseven USG

If you don't know what this is from the title, I probably don't want to hear what you have to say about it. Otherwise, tell me what you think.
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  #2  
Old April 1st, 2007, 07:47 AM
Eric Siepmann
 
Posts: n/a
I'd have to have some range time with it for a definitive opinion, but some observations:

Capacity benefits the military more than anyone else.

The "flat" shooting round comes at a cost. Hard to find and expensive. However, good placement is a key when shooting defensively and the low recoil of the round would be welcome in this respect.

Personally, for home defense the shotgun suits my purposes the best. For casual shooting the cost of and difficulty finding rounds makes it a poor choice when I can find .45ACP at any range.

S&W, Springfield XD and Glock offer similar and proven models. I really liked the S&W over the Springfield XD. But will most likely spend the quarterly bonus on a Glock.

EwS
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  #3  
Old April 1st, 2007, 10:15 AM
ddavis ddavis is offline
Daniel Davis
 
Join Date: Oct 2006
Posts: 48
I agree. The main thing that really attracts me about it is the accuracy of the caliber. Also, the weapon is ridiculously lightweight. Some research on the internet indicates 30 percent less recoil than a 9mm, negligible differences in kinetic energy than a 45 and trajectory that lends itself amazing accuracy out to at least 100M. Check out the pic. Note the enlarged permanent/temporary cavities as the projectile goes into yaw/tumble and ends up rear forward in the gelatin. Very rarely exits. Amazing round.
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File Type: jpg penetration.jpg (5.5 KB, 72 views)
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  #4  
Old April 2nd, 2007, 09:06 AM
johnlee johnlee is online now
John Lee
K6YJ
 
Join Date: Sep 2003
Location: Torrance, CA
Posts: 16,147
I think the 5.7 round is an answer in search of a question.
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  #5  
Old April 2nd, 2007, 09:19 AM
thomaskimura thomaskimura is offline
Thomas Kimura
N6BZ
 
Join Date: Nov 2005
Posts: 178
I'm curious to see how these new rounds will be implemented. I like the HK MP7- kind of like an M1 Carbine for the 21st Century
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  #6  
Old April 2nd, 2007, 10:19 AM
ddavis ddavis is offline
Daniel Davis
 
Join Date: Oct 2006
Posts: 48
The input is appreciated. John, I was hoping you would jump on this thread and tell me something detailed that you might have come across in your reading. The threads on the .375 H&H caliber and other rifles really unveiled some great info that helped me in picking out a rifle for my father-in-law in AK. Anyone have definitive info on whether this weapon with this caliber is what it is cracked up to be?
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  #7  
Old April 2nd, 2007, 02:50 PM
johnlee johnlee is online now
John Lee
K6YJ
 
Join Date: Sep 2003
Location: Torrance, CA
Posts: 16,147
I'm not positive on the 5.7's ballistics because I am not interested in this cartridge, but I googled and found that the 5.7's ballistics from a pistol barrel are 28 grains @ 1900 f/s.

That's pathetic. The .22 mag from a rifle-length barrel is 30 grains @ 2200 f/s, which is about what the 5.7 generates from a long gun like the FN P90. There's basically no meaningful difference between the 5.7 and the .22 mag.

Now, I do not want to get shot with anything, but I do not believe 28 grains @ 1900 f/s can be a reliable stopper, no matter what the bullet construction is. Lead core, steel core, steel penetrator tip, teflon tactical bling bling, round-nose, truncated cone, wadcutter, semi-wadcutter, ball, soft-point, hollow-point, whatever. It still won't matter. There's no way a .224", 28-grain projectile @ 1900 f/s can deliver reliable stopping power. It just cannot be done.

The 5.7 x 28 is marketed in the tactical market as being able to penetrate Level IIA body armor. It very well might. The SS190 military load features construction similar to FN's SS109 load for the 5.56, with a hardened steel penetrator, thin jacket, and lead core. I do not believe these rounds are available to civilians, which takes away one of the 5.7's purported advantages over conventional pistol chamberings.

I don't understand the tactical niche of the 5.7 round or the weapons chambered therefor. A P90 chambered in 5.7 is a mystery to me. The P90 is not so small that it can be worn like a pistol. It must be be carried rather than worn like a pistol. If you are going to go to the trouble of carrying a long gun, why not carry a real weapon like a rifle? Sure, the P90 is smaller than a rifle, but it still must be borne rather than worn. And the P90 is not any smaller than a machine pistol, and armor-piercing loads for machine pistols have been around for decades. A P90 is not any more effective than an MP5 loaded with AP rounds for penetrating hard targets. And I would rather have the MP5 for soft targets.

The Five-seveN pistol is a mystery to me as well. Sure, it penetrates IIA body armor, but so does armor-piercing 9mm Luger. A 9mm pistol loaded with AP would do the body armor thing just as well, and it would not be as specialized a weapon as a Five-seveN.

Why the need for a different caliber at all? The 5.7 is not any more intrinsically accurate than the 9mm Luger. The 5.7 may have a flatter trajectory, but the difference is minimal at ranges up to 100 yards, and 5.7's effective range is 100 yards or less.




That gelatin profile isn't that impressive to me. The projectile is still in one piece, which means to me that the permanent cavitation is probably very small. Some small-caliber rounds like the 5.56 are adequately effective because they fragment in tissue (at least at short ranges). The SS109, for example, typically breaks into multiple pieces and the broken pieces are still large enough to create independent wound channels (permanent cavitation) of their own. Pieces of flesh between the independent wound channels is often completely detached/shredded by the large temporary cavitation.

In contrast, the 5.7 does not seem to generate the velocity necessary to cause the ball rounds to frag. And I doubt the temporary cavitation caused at 1900 f/s is large enough to stretch the issue beyond its elastic limits and become torn/shredded.

The 5.7 does not seem suitable for "soft" ammunition either. If the ammunition factories loaded the 5.7 with a soft-point or hollow-point to make the round frag or expand, then penetration would have to fall below acceptable levels. Remember, the projectile weighs only 28 grains. Even the punk ass 9mm Luger projectile weighs 115 grains. 28 grains is dinky. Any loss of sectional density in the 5.7's projectile caused by expansion or fragmentation would surely decrease penetration to unacceptable levels. Even the ball load for 5.7 penetrates only 12" without any fragmentation at all.

If you have an itch for a 5.7, it would be very easy to duplicate the 5.7's ballistics for testing. Just get a .22 mag and shoot stuff with it. The results would be almost identical. Shoot at steel plates or whatever with a .22 mag and see if you're impressed.
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  #8  
Old April 2nd, 2007, 06:56 PM
ddavis ddavis is offline
Daniel Davis
 
Join Date: Oct 2006
Posts: 48
That explanation helps quite a bit. I was a little concerned of what I might hear about it concerning "stopping power". I'll update this thread with some details if I end up buying one.
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  #9  
Old April 2nd, 2007, 07:36 PM
johnlee johnlee is online now
John Lee
K6YJ
 
Join Date: Sep 2003
Location: Torrance, CA
Posts: 16,147
Dan, my previous post to you concerned stopping power and utility as a weapon because I thought that's what you were asking about. But if you're interested in the Five-seveN pistol or the 5.7 x 28 caliber for shits and giggles, I wouldn't let the stopping power thing stop you from buying one. There is more to enjoying shooting as a hobby than only life and death matters.
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