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Posted: 8/8/2014 8:17:39 AM EDT
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I have a spare SBR lower that I need to put a SBR upper on.
I have a shorty 9mm, .300 BO, 6.8 mm (ouch), and a full size 556. So looking for something new. Anyone use a AR57, the upper that uses FN PS90, 50 round mags and fires the 5.7mm? There's a version I've seen with a 6 inch barrel, threaded, that I could put my Sparrow supressor on. Anyone have one? Like, dislike? Quiet with the can? Accurate? Relaiable? Fun? Thanks, |
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I have had a 10.5" AR57 upper for about six years now. I got it as a 16" upper and cut the barrel down to go on one of my SBR'd lowers. I have a 3 lb. drop in Timney trigger in the lower so it bump fires from the shoulder like crazy. I also keep an AAC Ranger suppressor on it making it a sweet package. It's pretty cool the way the empty casings drop out the mag well. If i want to save the brass I have a gutted AR mag that acts like a brass catcher. It is very quiet with a 556 suppressor but I am not sure how loud it would be using a .22 suppressor. Not even sure the Sparrow is rated for the 5.7x28 round. That round puts out a hell of a fireball.
JMHO, MadDog |
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I bought a 16" upper. Decided I wanted to SBR it and bought a 6" barrel instead of cutting down the longer one. Haven't had any problems with it. Sparrow and Spectre are rated for the 5.7x28, and I opted for the Spectre II.
I'll tell you it's going to be tough to use the Sparrow on it if you plan on putting it on and taking it off much. The factory threads are going to be too long, so you'll either need to use a spacer, get them altered, or use the SiCo 1/2-28x1/2-28 adapter that has the o-ring engagement specs. I opted for the adapter, so it's a little longer than the 6" it would've been. With the Spectre II being ~1" longer than the Sparrow, I still only have this much sticking out the end: 
I use a 40rd PMag with the spring and follower removed as a brass catcher: 
I also have a 30rd PMag with the spring and follower removed, plus the baseplate gone. It would probably catch all 50, but in use it just to have another grip option. (In case you're looking closely, that's a fake can I had made to the same 1"x6" specs as the Spectre II so I could shoot it unsuppressed) |
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Quoted:
I bought a 16" upper. Decided I wanted to SBR it and bought a 6" barrel instead of cutting down the longer one. Haven't had any problems with it. Sparrow and Spectre are rated for the 5.7x28, and I opted for the Spectre II. I'll tell you it's going to be tough to use the Sparrow on it if you plan on putting it on and taking it off much. The factory threads are going to be too long, so you'll either need to use a spacer, get them altered, or use the SiCo 1/2-28x1/2-28 adapter that has the o-ring engagement specs. I opted for the adapter, so it's a little longer than the 6" it would've been. With the Spectre II being ~1" longer than the Sparrow, I still only have this much sticking out the end: http://i751.photobucket.com/albums/xx151/thegreghorton/Mobile%20Uploads/1F8CFE8B-6A76-4DFC-8368-612BE2E23291_zpsbx8qaoeh.jpg I use a 40rd PMag with the spring and follower removed as a brass catcher: http://i751.photobucket.com/albums/xx151/thegreghorton/Mobile%20Uploads/29006348-F774-4F53-AF06-96CD0AAAC9EB_zpsainoynch.jpg I also have a 30rd PMag with the spring and follower removed, plus the baseplate gone. It would probably catch all 50, but in use it just to have another grip option. (In case you're looking closely, that's a fake can I had made to the same 1"x6" specs as the Spectre II so I could shoot it unsuppressed) Damn that gun is cool as hell!! I like the idea of 5.7 as a PDW round in SBR or sub style gun in place of something like 9mm, but I really don't like the price of the ammo. At 50+ cpr is about twice as high as 9mm. |
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Quoted:
Damn that gun is cool as hell!! I like the idea of 5.7 as a PDW round in SBR or sub style gun in place of something like 9mm, but I really don't like the price of the ammo. At 50+ cpr is about twice as high as 9mm. It's a neat little package, especially if you remove the PMag or were to swap to a 10rd or 20rd. I know guys that hunt small game with them, and 50rds will last you awhile on a hunt. I've generally paid 40-50 cpr, as you can find the AE ammo on the shelf pretty regularly, and some places online will put it on sale occasionally. I haven't taken mine to the range with the newly arrived Spectre, but SS has videos of the round (out of a pistol) using the Spectre II, the Sparrow, and the Axiom. Probably kit much different than the 6" SBR. Not as quiet as 22LR, but still decent. |
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Quoted:
So the AR57 had a thread that is normal AR lenght, of 0.625", compared to a .22 thread of 0.4"? I have a spacer that will fill the gap. How's accuracy and reliablity with that set up? Normal length AR threads. Had one or two rounds of AR ammo get jammed up, out of several hundred, and that's about it. Haven't shot it much at the 6" length, but accuracy is pretty good at the short distances I've been able to shoot. It's not moving as quick as .223, but it's a lot faster than 22LR. |
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