The Fiveseven gets a big brother.

Discuss the variety of handguns out there.
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Snaproll
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The Fiveseven gets a big brother.

Post by Snaproll » 14 Jan 2012, 11:36

Recently I picked up a Rock River LAR-PDS. This is basically an AR-15 with a 9" barrel but qualifies as "just a handgun". It is not a SBR or AOW (as long as no foregrip or shoulder stock is added).

Rock River came up with a very interesting design. Note there is no buffer tube. Instead they developed a PDS (Piston Drive System) similar to an AK. The charge handle is above the foregrip but does not cycle when the gun is fired.

I've made some mods to the original gun. It doesn't come with sights, just a picatinny rail on top and under the barrel. I added a gen 3 Veridian light/green laser under the barrel. Originally I put a holosight on the upper rail but replaced it with a Barska 1-3 power illuminated scope. (The gun was more accurate than the holosight at 100 so I went with a variable 3 power. Also the scope's crosshairs illuminate, but if the batteries go dead, the scope could still be used where the holosight could not).

With the short barrel the gun is pretty loud. It comes with an A2 flash suppressor so I added a Noveske "Pig". These are supposed to "channel the noise down range" but it is still plenty loud. I measured it today and it was at 106 db. By contrast my friend's AR with a 14" barrel was 108, so it's in the same range.(Surprisingly the Fiveseven measured 118 db). Our range has a roof overhang above the shooting benches. The Rock here was actucally shaking snow off the roof with the concussion. I think the main deal that makes the gun seem so much louder is the fact that with the short barrel it's more "under" the roof and thereby has a lot of reverberation. Either way, since I didn't check the sound signature with just the A2 I don't have an idea if "the Pig" actually works to cut down on the noise to those on either side of the gun.

There is a vertical picatinny rail on the back if someone wanted to add a shoulder stock and go SBR. I added a single point attachment there and a single point sling. It's a very comfortable carry.

Overall I am very impressed with the gun. At 100 yards I'm shooting 3 inch groups just bench resting with cheap 55 gain UMC ammo. The trigger is crisp and probably in the 3-4 pound range. The 1-9 twist is middle of the road so it can probably shoot a wide variety of 556/233 ammo. The gas port can be selected for high or low volume if you're shooting low power ammo. I haven't had a single feed issue, the gun is a rock steady performer. (I did however get a 60 round Surefire mag to try out. Pass on that thing, it jams about every 5 rounds towards the end).

Basically I picked this thing up as a "brush gun" for when my wife and I head to remote locations for astronomy or birding. (We go to places where there are no lights and little civilization in northern Wisconsin, Michigan and Minnisota. The kind of places where you can hear distant strains of banjo music if you catch my drift). I used to carry an AR-15 or 870 zombie gun on these trips, places where there is a possiblility of bears but more so the likes of poachers and little of no LEO around. Places where you just feel a little exposed packing only handguns. The AR and Express fit the bill for "insurance" purposes, but they are always so big, bulky and heavy to pack. "The Beast" as we call this little guy fits the bill for us perfectly. Nice and compact, easily fits in the vehicle and out of the way unless we would need it. Since it is "a handgun" it would probably be legal to have it loaded as a CCW. With the scope it's good for a couple hundred yards in the day and with the green laser/light it would still be good at night for at least 100 yards.

Anyway, it's kind of unique so I thought I'd share it in anyone was interested.

I'm trying to post an image I did in photobucket but it won't allow the post because "the image size can't be determined". I'm not sure how to fix this, so here's the URL instead.

Image
Last edited by Rapier1772 on 14 Jan 2012, 19:40, edited 4 times in total.
Reason: Fixed img tag

Snaproll
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Re: The Fiveseven gets a big brother.

Post by Snaproll » 14 Jan 2012, 11:40

Oh I also added a Magpul pistol grip. The gun comes with a Houge but I don't like the rubber "squishy" feel. The Magpul can be customized with different inserts, so I made the grip long like the Fiveseven. I have a large hand and really love the feel of the Fiveseven, and the Magpul is similar. It also has a compartment for batteries and an allen wrench to adjust the laser in the field.

srt-4_jon
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Re: The Fiveseven gets a big brother.

Post by srt-4_jon » 14 Jan 2012, 11:45

nice gun. i love me a piston ar.
fwiw, whatever you are using to record the sound wont work on a gun. if it was really only 108db, it would be quieter than a suppressed 22lr. gunshot sound is so fast most sound meters wont read it right. the kind that will cost thousands.

Snaproll
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Re: The Fiveseven gets a big brother.

Post by Snaproll » 14 Jan 2012, 11:49

srt-4_jon wrote:nice gun. i love me a piston ar.
fwiw, whatever you are using to record the sound wont work on a gun. if it was really only 108db, it would be quieter than a suppressed 22lr. gunshot sound is so fast most sound meters wont read it right. the kind that will cost thousands.
Thanks for the info. Yeah, this is something I picked up a few years ago to measure noise in my cockpit. I never used it with a gun before. It makes sense though about the duration of the noise. This little Rock River does seem to be a good bit louder than an AR, kind of a "sharper crack". Last week my wife was gunning next to me and said she could really "feel" the concussion/shockwave. It was actually zining one of her tooth fillings...

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blueorison
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Re: The Fiveseven gets a big brother.

Post by blueorison » 14 Jan 2012, 19:13

Snaproll.

Great, chill review of the pistol. I didn't know about it till you posted it, and checked it out. I liked the design a LOT!!! I thought it was going to be one of those ______ AR pistols with the ______ tube stocks sticking out that really serve no _______ purpose and detracts from the functionality of the gun. Don't know much about mechanics of guns, but it sounds like a working design. I also like what Rock River does with their company. They aren't some wannabe's that make useless tactical crap to saturate the market that is already supersaturated.

I use their products a lot, especially when competing in CMP Highpower (I like to call it Hipower, because you say hi to something really far away). I use their rifles and their old school stuff. Also their triggers, which cannot be beat for value and reliability (other close-priced triggers are sometimes ok but go FA occasionally or do things they shouldn't).

Their design is very FUNCTION-driven. You can tell. There are no unnecessary excessive rails tacked on every open area of the gun. I like the tail rail on which you can mount slings. It will make your gun more balanced when carried on the sling, instead of having tension on one side/point on which the balance isn't very comfortable. NICE. Go RRA.

Glad you purchased it and posted about it. Thanks, dude.
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Snaproll
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Re: The Fiveseven gets a big brother.

Post by Snaproll » 15 Jan 2012, 06:31

One thing I was concerned with was the recoil. I thought it would be heavy but it is surprisingly light. The gun itself is heavy, like a brick. THa tflash suppressor adds another 7 ounces as well. Overall, it weighs over 5 lbs, but is well balanced, maybe a bit nose heavy. Anyway, the combination makes the recoil easily managable even with your eye close to the scope.

Correct there is no buffer tube. On an AR, the bolt pushes into the buttstock where there is a recoil spring and buffer plug. On the original AR this was not a problem as it was a rifle. Then they wanted to shorten it so there was the "carbine" version, but there was no way to get rid of the that buffer tube. The stocks just collapsed back along the buffer tube. Most of these AR pistols end up with the buffer tube sticking out the back and to me, looking really stupid, like some kind of weird growth was coming out of the gun. The deal with Rock River is that the gas port goes through an adjustable valve at the end of the barrel and up to a chamber where there is a piston. The piston in turn pushes on a rod that is attached to the bolt, driving it back. The rod is hollow and has a return spring in it. Basically the action is similar to that of an AK where the return spring is above the barrel. If you're familiar with an AR, kind of picture a return spring inside the gas tube and attached to the end of the reciever like an AK. In any event, they get rid of the tube sticking out the back.

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