barnbwt
member
- Joined
- Aug 14, 2011
- Messages
- 7,340
I'll say first off, that ordinarily I'd be steaming mad at the performance I experienced, but so much was going so wrong in so many ways generally, that it couldn't all have been Kel Tec's fault. I'll say second off, that my current favorite rifle --the PS90-- had a similarly tortuous debut* but flawless performance thereafter that only got better. So I'm definitely giving the gun another chance before I start complaining for real. Let's call it an inauspicious start, rather than a failure for the time being 
So, the first issue I ran into, as have many others before me, was that the gas was too lean as delivered (this gun is technically used but hardly fired, but the gas valve was fully open for weak cycling). The gas valve is a lot easier to turn than I expected, or would prefer, but didn't manage to move on its own. Because the RDB extracts the spent case over the top of the mag before ejecting, weak cycle force means it stops short, and returns the spent case as well as the next live round into the barrel extension, wedging both in a bizzare and nasty malfuction that utterly ruins both pieces of brass as well as the one bullet (basically breaks the rounds in half). Further, the only remedy is to take the gun apart at the takedown pins to fix it, unless you've got a screwdriver handy to pry with. Naturally, I was too impatient to properly lube the gun before heading out, which surely did not help.
Sounds bad, and it is, but the fact of the matter is that a proper gas adjustment makes it a total non-issue in practice, as I found when I gave it a bit more gas; no more crazy double feeds. Sadly, this was not the end of the malfunctions, however. The other issue with the gun as it is currently, is that it really, really, REALLY does not like USGI mags. 2nd gen P-mags fit like a glove, with a nice positive latch into the mag catch, and no wobble. Metal mags are like a hot-dog down a hallway by comparison, and seem like they stop short against the bolt before the catch fully engages. I think the U-clip mag catch doesn't bow in far enough to properly engage the narrower metal mags, but I don't know if there is an unavoidable reason for this design flaw. The result was the 30rnd aluminum mag I borrowed (a box of ten P-mags arrived at my door during the range trip, but I didn't want to wait) fell out with every shot, and no, it wasn't due to me bopping the release under recoil (it's actually surprisingly hard to hit accidentally unless you really keep your elbow tucked back & up). A 20rnd metal mag worked slightly better, in that it at least stayed in the gun, but suffered near-constant misfeeds. Like I said, both mags felt as though they were hitting the bolt when inserted, but none of the P-mags I tested later on had the same issue.
Comically enough, I got my best strings of fire out of the drop-prone 30 rounder, tea-cupping its baseplate while shooting from a squat position. Actually got pretty reliable hits on a 150yd gong using the SIG red dot sight I'd brought (which worked fine despite some workmanship flaws) from this funky off-hand position. But take my hand off that mag and it'd pop right off before the next round could strip, and I was able to pull it out without hitting the release. Worst part of all this, apart from remembering I'd heard of the USGI mag issue months earlier on the drive home, and finding a new box of P-mags on my doorstep to mock me, was that the RDB came with it's own P-mag, which had hidden itself under the packaging/documentation that came with the rifle. Balls.
The sling Kel Tec supplied is both cheap & strange. Not sure exactly how it's supposed to work, but there's one non-adjustable clasp at on end, and a second clasp that's meant to be moveable inside an adjustment loop secured by two friction buckles & securing links (not sure why you'd need two, though, and the sling is about twice as long as needed). Very crude design you wrap your elbow through once or twice to put some tension on the fore end. I suppose it's just that so few know how slings are supposed to work that we get these straps that aren't good for much besides carrying the rifle in an insecure manner. Makes position shooting a bit easier, which is what I bought the rifle for, but the barrel is not actually free-floated so I'm sure it impacts ultimate accuracy (not that I'm noticing with a red-dot 1X sight). I found that compounding recoil tended to almost knock me over from the squat position, usually the muzzle is far enough out that it balances, so that will take a little getting used to.
Very nice trigger, a very slick hammer design that I'm surprised isn't more common in bullpups. Basically, instead of a complete trigger group the trigger is linkaged to, resulting in a poor trigger pull associated with bullpups, the RDB has a complete trigger/sear/disconnector right at the pistol grip, and instead of the sear releasing the hammer directly, it releases a linkage that is driven by two stout springs to power the remote (U-shaped) hammer at the rear. The hammer also has a 2-3" pivot arm and travel distance, so it truth it acts more like a striker on an incline. Probably not great for lock time, but you get a light, tight trigger with no slop & little over travel to release a powerful striking element a good ten inches to the rear.
One item I've noticed, primarily because of all the dissassembly I've been doing, is that the takedown pins are both a lot stiffer & tighter than is needed (considering they aren't doing anything requiring precision), and that there's three of them. Now, to define a line, you need to points; this is how the AR15, HK G3, and most other push-pin guns work. No matter how those pins get placed, as long as the distance between them is in-spec they'll generally fit the two halves together without drama. But with three pins, three tight pins that go through three separate parts at that (upper, lower, cheek piece/top cover all share pins), it gets really annoying to align the planets so the pin can be tapped through. The fact these parts are sprung against eachother by the return spring assembly makes it even harder; nearly a three-hand operation at times (at others, surprisingly easy). I get the feeling that if the cheek piece were a bit stiffer, they could get away with only two pins & make assembly a lot easier, but the root issue that the front/rear pins are over a foot apart from eachother.
Now, I didn't have the D60 drum pictured with me at the time (it fits as well as the other Pmags, naturally) because it managed to murder itself a couple days before the trip --so much misfortune surrounding this cluster of a range day-- as well as rip off the end of my trigger fingernail (shooting & typing's been fun lately). I won't say it's comfortable, since the inside of wrist does somewhat contact the edge of the drum, but if a 'chicken-wing' hold is used, it's entirely practical to use this mag, and even fully loaded, the balance is very near the shooting hand. Further, the drums are quite reliable so long as you are damned careful when unloading them (screw that, I'll just shoot them dry going forward), so once I rig up a brass catcher to go behind it, I'll have a very handy little carbine that packs quite a lot of firepower into a self-contained package.
So, summary of the Kel Tec side of the equation vs. barnbwt-being-an-unlucky-idiot side of the equation; finnicky on mags, though it seems there are a handful of guns that can only use USGI mags & hate Pmags so maybe that's a wash. Requires a proper gas adjustment ahead of time if you want to avoid obnoxious field service shenanigans, but that kind of goes for most auto-loaders (it's still easier than my FN49, at least). The gun seems solid & pretty well made, up there with an ARX or most ARs, perhaps better, though there are still occaisonal mold-flashes & rough spots like the tight takedown pins. Trigger is quite good for a bullpup, easily competitive with any non-match trigger. Recoil impulse is an odd double-take that reminds me of roller-lock guns, due to the bolt travel being roughly twice as long as usual, which greatly slows down the cyclic speed to where you can detect the bolt returning. Human machineguns will probably have issues with hammer follow during rapid or bump fire, but I'd bet a select-fire variant is quite controllable. Recoil force is quite light, better than a VZ58 or AR70 anyway, and well-damped by the long bolt travel. Muzzle blast wasn't nearly as bad as I'd expect for a bird-cage omni-directional type so close to my face with a 16"-ish barrel. I think a big factor is the foregrip 'flare' near the muzzle blocks a good portion of the concussion, since I did feel it off to the side while my buddy was shooting, but still nothing a simple set of good earmuffs couldn't cure (I usually have to do plugs and muffs with 5.56, but I swear the sound this gun makes is an octave lower or something, and far less obnoxious than most M4geries I've been near)
I think Kel Tec's got a winner here, for sure. There are a few easy and very minor tweaks that need to be, and will be made, but the concept is solid, the execution is pretty solid, and some aftermarket development & OEM accessory support will make it every bit the contender as the Tavor (minus the Israel fanboy stuff; as if Florida Man doesn't have it just as rough as the IDF)
Now, if you don't believe that this was the Freaky Friday of gun range trips, me & my shooting partner managed to meet constant malfunction in; the RDB, a 6.5 Grendel (this dope brought the wrong bolt-head along), my MP5SD/UMP mutt build which has somehow stopped hitting primers, a belt-fed 9mm upper (they don't like the Geissele triggers), and even a USP40 which was having FTE problems for a mag or two. Several of our optical/iron sights were mysteriously off, and the sand pit constantly blows fine white sugar sand into everything so as to muck stuff up generally. Naturally my 7mm rolling block and K31 were flawless examples of reliability, as always --sometimes I wonder why we bother innovating
TCB
*Constant malfunction, dot-sight battery failure & horribly misaligned backup 'sights' if you can call them that, double feed that could have caused a kaboom (bullet into primer), charging handle launched down range, and the piece de resistance was pinching my palm between the mag & receiver so badly the gun was hanging from it until I hit the release & raised a nasty 1" long blood blister. Literally *ONE* failure to feed has occurred in the five hundred rounds I've shot subsequently, this using the 10$ Korean knock-off mags
So, the first issue I ran into, as have many others before me, was that the gas was too lean as delivered (this gun is technically used but hardly fired, but the gas valve was fully open for weak cycling). The gas valve is a lot easier to turn than I expected, or would prefer, but didn't manage to move on its own. Because the RDB extracts the spent case over the top of the mag before ejecting, weak cycle force means it stops short, and returns the spent case as well as the next live round into the barrel extension, wedging both in a bizzare and nasty malfuction that utterly ruins both pieces of brass as well as the one bullet (basically breaks the rounds in half). Further, the only remedy is to take the gun apart at the takedown pins to fix it, unless you've got a screwdriver handy to pry with. Naturally, I was too impatient to properly lube the gun before heading out, which surely did not help.
Sounds bad, and it is, but the fact of the matter is that a proper gas adjustment makes it a total non-issue in practice, as I found when I gave it a bit more gas; no more crazy double feeds. Sadly, this was not the end of the malfunctions, however. The other issue with the gun as it is currently, is that it really, really, REALLY does not like USGI mags. 2nd gen P-mags fit like a glove, with a nice positive latch into the mag catch, and no wobble. Metal mags are like a hot-dog down a hallway by comparison, and seem like they stop short against the bolt before the catch fully engages. I think the U-clip mag catch doesn't bow in far enough to properly engage the narrower metal mags, but I don't know if there is an unavoidable reason for this design flaw. The result was the 30rnd aluminum mag I borrowed (a box of ten P-mags arrived at my door during the range trip, but I didn't want to wait) fell out with every shot, and no, it wasn't due to me bopping the release under recoil (it's actually surprisingly hard to hit accidentally unless you really keep your elbow tucked back & up). A 20rnd metal mag worked slightly better, in that it at least stayed in the gun, but suffered near-constant misfeeds. Like I said, both mags felt as though they were hitting the bolt when inserted, but none of the P-mags I tested later on had the same issue.
Comically enough, I got my best strings of fire out of the drop-prone 30 rounder, tea-cupping its baseplate while shooting from a squat position. Actually got pretty reliable hits on a 150yd gong using the SIG red dot sight I'd brought (which worked fine despite some workmanship flaws) from this funky off-hand position. But take my hand off that mag and it'd pop right off before the next round could strip, and I was able to pull it out without hitting the release. Worst part of all this, apart from remembering I'd heard of the USGI mag issue months earlier on the drive home, and finding a new box of P-mags on my doorstep to mock me, was that the RDB came with it's own P-mag, which had hidden itself under the packaging/documentation that came with the rifle. Balls.
The sling Kel Tec supplied is both cheap & strange. Not sure exactly how it's supposed to work, but there's one non-adjustable clasp at on end, and a second clasp that's meant to be moveable inside an adjustment loop secured by two friction buckles & securing links (not sure why you'd need two, though, and the sling is about twice as long as needed). Very crude design you wrap your elbow through once or twice to put some tension on the fore end. I suppose it's just that so few know how slings are supposed to work that we get these straps that aren't good for much besides carrying the rifle in an insecure manner. Makes position shooting a bit easier, which is what I bought the rifle for, but the barrel is not actually free-floated so I'm sure it impacts ultimate accuracy (not that I'm noticing with a red-dot 1X sight). I found that compounding recoil tended to almost knock me over from the squat position, usually the muzzle is far enough out that it balances, so that will take a little getting used to.
Very nice trigger, a very slick hammer design that I'm surprised isn't more common in bullpups. Basically, instead of a complete trigger group the trigger is linkaged to, resulting in a poor trigger pull associated with bullpups, the RDB has a complete trigger/sear/disconnector right at the pistol grip, and instead of the sear releasing the hammer directly, it releases a linkage that is driven by two stout springs to power the remote (U-shaped) hammer at the rear. The hammer also has a 2-3" pivot arm and travel distance, so it truth it acts more like a striker on an incline. Probably not great for lock time, but you get a light, tight trigger with no slop & little over travel to release a powerful striking element a good ten inches to the rear.
One item I've noticed, primarily because of all the dissassembly I've been doing, is that the takedown pins are both a lot stiffer & tighter than is needed (considering they aren't doing anything requiring precision), and that there's three of them. Now, to define a line, you need to points; this is how the AR15, HK G3, and most other push-pin guns work. No matter how those pins get placed, as long as the distance between them is in-spec they'll generally fit the two halves together without drama. But with three pins, three tight pins that go through three separate parts at that (upper, lower, cheek piece/top cover all share pins), it gets really annoying to align the planets so the pin can be tapped through. The fact these parts are sprung against eachother by the return spring assembly makes it even harder; nearly a three-hand operation at times (at others, surprisingly easy). I get the feeling that if the cheek piece were a bit stiffer, they could get away with only two pins & make assembly a lot easier, but the root issue that the front/rear pins are over a foot apart from eachother.
Now, I didn't have the D60 drum pictured with me at the time (it fits as well as the other Pmags, naturally) because it managed to murder itself a couple days before the trip --so much misfortune surrounding this cluster of a range day-- as well as rip off the end of my trigger fingernail (shooting & typing's been fun lately). I won't say it's comfortable, since the inside of wrist does somewhat contact the edge of the drum, but if a 'chicken-wing' hold is used, it's entirely practical to use this mag, and even fully loaded, the balance is very near the shooting hand. Further, the drums are quite reliable so long as you are damned careful when unloading them (screw that, I'll just shoot them dry going forward), so once I rig up a brass catcher to go behind it, I'll have a very handy little carbine that packs quite a lot of firepower into a self-contained package.
So, summary of the Kel Tec side of the equation vs. barnbwt-being-an-unlucky-idiot side of the equation; finnicky on mags, though it seems there are a handful of guns that can only use USGI mags & hate Pmags so maybe that's a wash. Requires a proper gas adjustment ahead of time if you want to avoid obnoxious field service shenanigans, but that kind of goes for most auto-loaders (it's still easier than my FN49, at least). The gun seems solid & pretty well made, up there with an ARX or most ARs, perhaps better, though there are still occaisonal mold-flashes & rough spots like the tight takedown pins. Trigger is quite good for a bullpup, easily competitive with any non-match trigger. Recoil impulse is an odd double-take that reminds me of roller-lock guns, due to the bolt travel being roughly twice as long as usual, which greatly slows down the cyclic speed to where you can detect the bolt returning. Human machineguns will probably have issues with hammer follow during rapid or bump fire, but I'd bet a select-fire variant is quite controllable. Recoil force is quite light, better than a VZ58 or AR70 anyway, and well-damped by the long bolt travel. Muzzle blast wasn't nearly as bad as I'd expect for a bird-cage omni-directional type so close to my face with a 16"-ish barrel. I think a big factor is the foregrip 'flare' near the muzzle blocks a good portion of the concussion, since I did feel it off to the side while my buddy was shooting, but still nothing a simple set of good earmuffs couldn't cure (I usually have to do plugs and muffs with 5.56, but I swear the sound this gun makes is an octave lower or something, and far less obnoxious than most M4geries I've been near)
I think Kel Tec's got a winner here, for sure. There are a few easy and very minor tweaks that need to be, and will be made, but the concept is solid, the execution is pretty solid, and some aftermarket development & OEM accessory support will make it every bit the contender as the Tavor (minus the Israel fanboy stuff; as if Florida Man doesn't have it just as rough as the IDF
)
Now, if you don't believe that this was the Freaky Friday of gun range trips, me & my shooting partner managed to meet constant malfunction in; the RDB, a 6.5 Grendel (this dope brought the wrong bolt-head along), my MP5SD/UMP mutt build which has somehow stopped hitting primers, a belt-fed 9mm upper (they don't like the Geissele triggers), and even a USP40 which was having FTE problems for a mag or two. Several of our optical/iron sights were mysteriously off, and the sand pit constantly blows fine white sugar sand into everything so as to muck stuff up generally. Naturally my 7mm rolling block and K31 were flawless examples of reliability, as always --sometimes I wonder why we bother innovating
TCB
*Constant malfunction, dot-sight battery failure & horribly misaligned backup 'sights' if you can call them that, double feed that could have caused a kaboom (bullet into primer), charging handle launched down range, and the piece de resistance was pinching my palm between the mag & receiver so badly the gun was hanging from it until I hit the release & raised a nasty 1" long blood blister. Literally *ONE* failure to feed has occurred in the five hundred rounds I've shot subsequently, this using the 10$ Korean knock-off mags
