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Posted: 11/1/2006 10:46:36 AM EDT
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Does anyone make a FN 5.7 caliber conversion for an AR-15? Why doesn't somone make a conversion in calibers like .44mag, .357 sig or mag, etc... of exceptional quality and accuracy? |
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Yes someone makes a 5.7 upper - and it takes P90 magazines - it ejects through the magazine port. The question is why? THere is a thread with pics in it. It should be in the Archive server. You could also check in the Pistol Calibers or AR Varients section. Uppers have been made in .44Mag and .44 Auto Mag by Tony Rumor of Tromix fame, and IIRC Kurt Wala (Kurt's Kustom) has make .357 Sig uppers. They aren't mass produced because there is little demand as they do nothing better than exisiting solutions. The .458 provide better ballistics and can use standard magazines if your looking for a large caliber AR, and 9mm uppers provide pretty much the same capability as the .357 Sig uppers with better ammo and magazine availability. |
I was going to buy one as an upper for my first rifle. I got tired of waiting after six months, so I got an AR. Thomas @ Rhineland is a good fellow, and the rest of their products sound like quality stuff, but given the costs of 5.7x28, P90 mags, and the lack of product after the time they said they would have stuff ready by, I gave up and went elsewhere. I might pick up an AR5.7 for shits and giggles, but that's not high on the list of Guns Which Must Be Bought. |
The only thing .357 sig has in common with 9mm parabellum is a .355 bullet. The .357 sig has a flatter trajectory and more energy. I just think the .357 sig wold make a devastating CQB weapon. |
Hardly. I'd be a pistol round that makes more flash and more muzzle blast, still won't penetrate body armor, more expensive to practice with, and more difficult to supress (plenty of subsonic 147gr 9mm - how about the .357?). You want a 'devestating' CQB weapon then get a 12" 6.8SPC stocked with 110gr VMAX or a 5.55 with 75gr TAP, if you want a quiet one there are 9mm and .45 ACP uppers, |
the 5.7 is already a dead caliber. Ultra high velocity/armor penetration was the reason the Five seveN was created, right? They've already refused to provide us common folk with the hot ammo, unless you can load your own rounds to the specs that they're supposed to be I don't see the point 
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There are so many inaccuracies in the above statement that I can only suggest you expand you research base. |
It's not quite that the ammo is so hot. The standard ball round (SS190) is aluminum cored with a steel penetrator; it's designed to pierce armour. As a handgun round (the PS90 is basically a pistol caliber carbine dressed up real fancy, and the P90 is basically an SMG) it's sale is restricted. SS195 is the standard self defense round for civilians who use weapons chambered in 5.7x28, and it's a 28 gr aluminum round with a copper full metal jacket. In other words, it's the bullet, not the amount of powder behind it. |
I stand corrected. My point, however, was still made. We can't buy the SS190 can we? Just seems like the weapon is being sold without the ammunition it was really designed for beng available. No point in buying it to me, if I could get SS190 it might start to look appealing. YMMV 
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I wouldn't feel undergunned with a FN5.7 loaded with SS195. If I had a choice, though, I'd use a 1911 with 230 gr JHPs. Anything larger, and I'd use an AR. |
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I'm not sure if the post is directed at my statement or not but it'd be a naive assumption for someone to postulate on my knowledge regarding the 357 SIG.  Both the 9mm & 357 SIG have the capability to penetrate body armor in certain instances with specific loadings when using an SMG or pistol carbine. The 9mm is to the 357 SIG as the .40 S&W is to the 10mm. Muzzle blast and flash is a red herring argument... Energy can certainly be argued but quantifying it with qualified data is an entirely different matter that the theorists still have trouble resolving.  If I was making the choice of on a shoulder fired CQB/CQC carbine it’d be a derivative of a 5.56 or 6.8 weapons platform. However, my sidearm may well be stoked with the 357 SIG cartridge! 
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I'm all ears. Please name 1 inaccuracy and back it up with data from a peer reviewed source. Thanks. |
In fact quite the opposite - the only thing is I don't folow gun-rag B.S. I will accept date from peer reviewd publications that follow the IWBA or FBI testing protocols.
Yes one can if one true understands terminal ballistics and the concept of 'permanent crush cavity'. The only thing that metters with these small service rounds is how much tissue they destroy and if they can make the minimum required penetration depth. If one looks at the available data the .357 Sis doesn't make holes significantly bigger than the 9mm.
Energy, as pointed out is irrelavent - it's dammage that counts. Also, you then have to deal with pistol bullets that may be moving TOO FAST for their design and break apart - thus you end up with less penetration and tissue distruction. Fragmentation can be a good thing with a rifle bullet which makes a significant temporary cavity, but with handgun bullets the temporary cavity is too small so fragmentation is bad, you want a pistol bullet to stay together.
Never fired one huh? Yes it is worse.
Ok lets get real here, You are talking about specific rounds in very specific circumstances. Rounds that are unavailalbe to the public, and rounds that many police agencies won't even use because it would look bad in the press (PC run amoke)
I'd agree.
B.S. Half of violent encounters occure at night or in darkness. When your vision is disrupted because you're producing big white balls of flash that's a very real issue. Same with the blast. At least if you're going to have muzzle blast use a real caliber (5.56, 6.8 or 12 gauge) that will do some serious dammage and will still not have the bright flash.
My choices as well.
Curious, other than the lower magazine capacity, the muzzle blast/flash, and the enhanced recoil - what does the .357 Sig offer you that a decent 9mm round does not? |
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Winchester Ranger Data Bare Gelatin 9mm 147-gr: 13.9'' 357 SIG 125-gr: 10.9'' Denim (4 Layers) 9mm 147-gr: 14.5'' 357 SIG 125-gr: 12.1'' I have no clue as to what the performance would be out of a carbine or SMG, but these obviously represent handgun performance of said calibers. And yes, muzzle flash is quite noticeable when I had the 357 Sig barrel in my P229 SAS. It may serve many people well, but I personally went back to the 180-gr. 40S&W SXT. I think that many people automatically buy into the higher velocity = higher performance advertising of the round. I did, or I wouldn't have purchased the barrel for it. If I had only came to arfcom back then... |
Political correctness. |
The question at hand for our minutia banter was the 9mm & 357SIG from AR15's or SMG's ergo not the 5.7, and not in a service caliber handgun which most IWBA/FBI test protocol data represents. The inaccuracies of your statement could be representative of some pistol caliber comparison tests and do not reflect the expansion of said information to represent the correct comparison, and focus of the discussion. You know that muzzle flash comparison between service pistol vs. that of a SMG or carbine are two entirely different matters. And, you should recognize that flash is a result of powder selection, burn rate, and barrel length which isn’t a caliber specific item. Additionally, there are large variation between “practice” ammunition and “duty” ammunition in flash comparisons. Practice cost based solely on newly manufactured ammunition from retailers can certainly make 9mm a cheaper practice round; however, it does not accurately represent the cost of reloaded ammunition. At preset I’m unaware of “suppression” test between the 9mm & 357SIG, or widely manufactured sub-sonic loading in the 357SIG in the 130-150gr weight range. Which isn’t to say that they’re not possible or unavailable; rather, demand may not be dictating such a requirement. While your statements may be partially representative of pistol service caliber discussion it certainly isn’t inclusive of the SMG or carbine application which this discussion is premised on – and that is the point. |
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The .357 SIG's claim to fame is the muzzle energy. Why would you download it to make it subsonic? If you do that, you're right in the 9mm subsonic range, ie a .355 bullet in the 130-150gr range (9mm 147gr anyone?). So why in the hell would anyone make a suppressed .357SIG, the only difference is going to be capacity. In other words, you're giving it up with .357SIG. |
Unless we're discussing actual reliable and valid representative test on the matter from an SMG or carbine in 357SIG there nothing to discuss about the issue as everyone would be grasping at anecdotal evidence.
Yeah, that was the point since your statement seemed to be as dismissive as to the facts that those are realities given a person knows what they are in an SMG or carbine.
If you're basing your "flash" information on pistol tests or practice ammo instead of from a SMG, carbine, and duty ammo then yeah it's a red herring argument because we're looking at pistol vs. carbines etc.
Let's see a lower magazine capacity compared to only that of a 9mm, no difference in muzzle blast, flash, or recoil when compared to +p or +p+ 9mm depending on the load in comparison - no you and I have completely different opinions of the 357SIG. What does it offer – what do you really care if you take such an offense to a “may well might be” type statement? |
I believe the only logical argument for sub-sonic loadings in the 130-150gr weight area in the 357SIG would be the possible powder options to optimize burn rate and trajectory within a specific barrel length; or, maybe an even heavier projectile, although 150gr looks to be the heaviest available pistol round in .355”? But that's complete speculation as it's not my argument or contention... |
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