**Range report added February 27 on post 5**
I’m getting quite a collection of unfired guns I haven’t had a chance to shoot yet, with the wintry weather we’ve been getting around here. Here’s my latest.
I’ve always been a DI guy as far as ARs go (I've owned 8 ARs since the mid-1980s and the've all been DI) and never really felt the need to try a piston-based rifle. But, I saw this on the EE recently, and have always liked lightweight, short ARs, and with the very short barrel on this model (7.75”) I thought a piston system might makes sense and be a worthwhile mid-winter purchase—and Primary Weapons Systems do have a pretty good reputation for piston rifles. Here are my thoughts on the first few days.
The “Mod 1” version of the Diablo has a keymod rail (instead of picatinny) that looks to be a PWS-designed model and a PWS Triad flash hider. There are a couple of polymer picatinny side rail portions that I’ll never use but act as a rudimentary handstop. This is my first keymod rifle (just in time for M-LOK to become popular
!) but I like how slim it feels and how rail covers aren’t needed. I'm kicking around the idea of an AFG or AFGII but other than that I'll leave it empty.
The Triad is a three-vaned combination flash hider-compensator—it's 5 ounces lighter than the previous muzzle device used on the Diablo.
There’s also an four-way-adjustable gas block to adjust the amount of gas used to operate the action (it's right behind the flash hider).
It’s chambered in .223 Wylde, a chambering that’s supposed to accommodate 5.56mm and .223 ammunition, and, according to its Wikipedia page, “exploit the accuracy advantages of the .223 Remington chambering without pressure problems or compromising the functional reliability of semi-auto weapons like the AR15 family when using 5.56×45mm NATO military ammunition”. It’s usually found on rifles intended for top accuracy so its inclusion here is a little unexpected. I’ll take it, though! The barrel is a 1:8 twist. (I hope I don't create a rift in the space-time continuum by using an Aimpoint sight with a Holosun riser!)
The previous owner installed a MOE K2 grip on the rifle—I like Magpul AR pistol grips a lot (I even installed one on my UTAS-15), and while I prefer the original MOE grip on a larger rifle, I like how the more vertical grip angle of the K2 allow you to tuck your elbow down more easily. It's texture is very grippy without being too aggressive.
The rifle also comes with an ALG Defense trigger—I’ve has one in another AR before. The pull weight is about the same as a regular factory trigger but the pull is nice and smooth with no creep. There’s no castle nut on the rifle, but a device with QD attachments machined in. The buffer tube has an extended lip to reduce carrier tilt.
Here’s where the real difference from a standard AR is—the bolt.
It’s a long-stroke piston that’s attached directly to the bolt carrier—supposedly the long-stroke design also helps to reduce carrier tilt. It’s teflon-coated and pleasingly slick. I think earlier versions may have had the charging handle permanently affixed to the bolt, but this version has a removable bolt head to allow for removal and replacement of the charging handle.
This arrangement does make reassembly a little fussier—you kind of need three hands to guide the carrier, the charging handle while holding the rifle while ensuring the bolt head doesn't fall off. I've done it a couple of times and am getting the hang of it
Unusually, the bolt is spring loaded in the carrier. The additional material at the rear of the carrier is intended to extend dwell time to allow chamber pressure to drop.
So, what are my first impressions? I really like the balance, light weight and handiness of the rifle—it’s makes my 16” AR feel long and clunky. I like the ALG trigger, too. One initial disappointment is that my AT-15 mags require a bit of extra force to fully seat, and won't drop free. Once I get a chance to get out I'll update with a range report.
I’m getting quite a collection of unfired guns I haven’t had a chance to shoot yet, with the wintry weather we’ve been getting around here. Here’s my latest.
I’ve always been a DI guy as far as ARs go (I've owned 8 ARs since the mid-1980s and the've all been DI) and never really felt the need to try a piston-based rifle. But, I saw this on the EE recently, and have always liked lightweight, short ARs, and with the very short barrel on this model (7.75”) I thought a piston system might makes sense and be a worthwhile mid-winter purchase—and Primary Weapons Systems do have a pretty good reputation for piston rifles. Here are my thoughts on the first few days.
The “Mod 1” version of the Diablo has a keymod rail (instead of picatinny) that looks to be a PWS-designed model and a PWS Triad flash hider. There are a couple of polymer picatinny side rail portions that I’ll never use but act as a rudimentary handstop. This is my first keymod rifle (just in time for M-LOK to become popular
!) but I like how slim it feels and how rail covers aren’t needed. I'm kicking around the idea of an AFG or AFGII but other than that I'll leave it empty.The Triad is a three-vaned combination flash hider-compensator—it's 5 ounces lighter than the previous muzzle device used on the Diablo.
There’s also an four-way-adjustable gas block to adjust the amount of gas used to operate the action (it's right behind the flash hider).
It’s chambered in .223 Wylde, a chambering that’s supposed to accommodate 5.56mm and .223 ammunition, and, according to its Wikipedia page, “exploit the accuracy advantages of the .223 Remington chambering without pressure problems or compromising the functional reliability of semi-auto weapons like the AR15 family when using 5.56×45mm NATO military ammunition”. It’s usually found on rifles intended for top accuracy so its inclusion here is a little unexpected. I’ll take it, though! The barrel is a 1:8 twist. (I hope I don't create a rift in the space-time continuum by using an Aimpoint sight with a Holosun riser!)
The previous owner installed a MOE K2 grip on the rifle—I like Magpul AR pistol grips a lot (I even installed one on my UTAS-15), and while I prefer the original MOE grip on a larger rifle, I like how the more vertical grip angle of the K2 allow you to tuck your elbow down more easily. It's texture is very grippy without being too aggressive.
The rifle also comes with an ALG Defense trigger—I’ve has one in another AR before. The pull weight is about the same as a regular factory trigger but the pull is nice and smooth with no creep. There’s no castle nut on the rifle, but a device with QD attachments machined in. The buffer tube has an extended lip to reduce carrier tilt.
Here’s where the real difference from a standard AR is—the bolt.
It’s a long-stroke piston that’s attached directly to the bolt carrier—supposedly the long-stroke design also helps to reduce carrier tilt. It’s teflon-coated and pleasingly slick. I think earlier versions may have had the charging handle permanently affixed to the bolt, but this version has a removable bolt head to allow for removal and replacement of the charging handle.
This arrangement does make reassembly a little fussier—you kind of need three hands to guide the carrier, the charging handle while holding the rifle while ensuring the bolt head doesn't fall off. I've done it a couple of times and am getting the hang of it
Unusually, the bolt is spring loaded in the carrier. The additional material at the rear of the carrier is intended to extend dwell time to allow chamber pressure to drop.
So, what are my first impressions? I really like the balance, light weight and handiness of the rifle—it’s makes my 16” AR feel long and clunky. I like the ALG trigger, too. One initial disappointment is that my AT-15 mags require a bit of extra force to fully seat, and won't drop free. Once I get a chance to get out I'll update with a range report.
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