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[Build Sheet] KE Arms KP-9 9mm PCC: Plastic Pistol Caliber Carbine

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A few months ago, I got to shoot the InRangeTV Handgun Brutality match up in St. George, Utah. Part of the match included a pretty sweet prize table that was given out via random drawing. As luck would have it, I won a KE Arms KP-9 lower receiver!

I’ve been shooting a KP-15 lower for a couple of years and have always wanted the KP-9, so winning one was pretty perfect in my book.

Since then, I’ve been putting this lower through the paces and shooting it a lot in local USPSA matches, along with some 2-gun and other events.

I won’t keep you waiting, I fully recommend it.


I built this upper over 3 years ago during the pandemic out of parts from my parts box. Since then, I’ve made a few changes, but I’ve still put a lot of rounds through it.

While the upper wasn’t really what I was testing out while shooting this recently, it’s worth talking about. 

This Holosun optic is their open rifle optic with a huge window. I really like it because the dot is green and it’s built like a tank. Great for matches and great for beating up.

Why a second dot? Just to make USPSA stages a little easier. Those hard leans to my weak side are very difficult to get a sight picture on the main dot. An offset dot lines up perfectly.

The BCG is amazing, and I’ve loved it for years. Cryptic Coating isn’t a name you see a lot, but they’re a sleeper of a brand. I don’t know what black magic and dark incantations go into making their BCGs, but they survive a ton of abuse and have a coating that makes cleaning them stupid easy.

When KynSHOT first approached me years ago about reviewing their buffers, I was pretty skeptical. My first time shooting them, I was pretty hooked. In 5.56, the difference isn’t massive, but it’s enough to make a difference. For 9mm with a direct blowback PCC, it’s a huge gain and makes for a super flat shooting PCC. Stacking rounds on top of one another is very doable.

The Lancer handguard is okay. Honestly, I got it for a really good deal, and I wanted to try carbon fiber. For a PCC, I like it because it’s lightweight and handy. But it gets hot and retains heat more than my aluminum handguards. Not super fun when it’s 105 degrees out and you’re shooting a match all day.

I’ll go into some details about the Faxon barrel in a moment, but I really like it.


The real heart and soul of this build is the KP-9 lower and the RTS-2 REKLUSE trigger. Both are pretty awesome.

A KP-9 lower is polymer, if you didn’t know. It’s a one-piece design that combines the lower, grip, and buttstock into one glorious hunk of plastic.

Before you start spouting off about how weak plastic is, I would remind you that you shoot a Glock (probably) or some other plastic firearm like the S&W M&P, CZ P10, SIG P320, Springfield XD9, Steyr AUG, FN SCAR, or about five dozen other plastic guns. 

In the old days, making an AR-15 or, in our case, an AR-9 lower out of plastic was a pretty bad idea, but that’s because until KE Arms got in the game, everyone was basically just taking the specs for an AR-15, and trying to make it out of plastic.

I have a lower that was designed like that. It sits on my “Broken Sh!t” shelf.

The KP-9 is different. It’s actually designed as a whole new part and a whole new gun that actually works. From everything I’ve done to both the KP-15 and KP-9, these are stronger and lighter than anything else on the market. I wouldn’t call them perfect for every application, but they’re not far off from it.

Last but not least, the RTS-2 REKLUSE trigger is amazing. Crisp, snappy, and built to survive – I’m a huge fan. Read more in our Best AR-15 Triggers Buyer’s Guide.

On The Range

I love this PCC. It’s super lightweight at barely over 6 lbs, it’s easy to move with, and it’s a lot of fun to shoot. Recoil and muzzle rise are almost non-existent, it’s accurate, and the RTS-2 trigger is wonderful for quick and fast action.

For me, the length of pull on the KP-9 is almost perfect, and that’s how most people will feel about the 13” LOP.

I’m not a big USPSA shooter, but I’ve been shooting it a bunch as a test bed for this PCC. I’m a big believer in doing things on the clock and seeing what really happens when the rubber meets the road. 

With that in mind, this gun is pretty awesome. I’m not a speed shooter, but on stages where I don’t drop the ball, I’m finding it fairly easy to get very high A class scores. The KP-9 lower cuts so much weight off the gun that it makes it super easy to move quickly and get great hits.


Okay, so about that Faxon barrel. In one of those USPSA matches I shot, I was running low on 9mm, waiting for a new shipment. Digging around in my ammo room, I found a bunch of Beretta 92 magazines that I loaded up years ago and never shot. Since I was in a bind and low on time, I unloaded those mags and dumped the ammo into a sack to shoot the match with.

That was a bad idea. As best as I can tell, this was all 115gr ammo that I bought at least 3+ years ago, loaded, and never shot. They were not stored well, it was a mix of two brands, and I don’t know who the offender was, but one of those gave me problems almost all match.

A couple of FTEs early in the day, I assumed the issue was just that this was a build that I hadn’t fully tested out yet, and something was wrong mechanically. 

On my second to last stage of the day, I ripped off 6 or 7 rounds with no problem, then had what I thought was a failure to eject. I cleared it and kept shooting. Weirdly, none of my shots went where I sent them. I felt like those were good shots, but when the RO scored it, he called something like D, D, Mike, D, Mike, Mike, etc. Now I’m not the best USPSA shooter, but there was no way I sent multiple misses on that string.

Over at the safety area, I inspected the rifle, and oops… turns out that FTE was actually a squib. And then I kept shooting. The follow-up shots had burst the barrel, so those shots went wild down range.

To be totally clear, this wasn’t the barrel’s fault. It wasn’t the lower, the BCG, or anything else with the rifle. This was purely the ammo.

I’m not sure if this was a bad batch of ammo, or if something happened during the 3+ years I had it in storage. I rarely buy ammo in lots lower than 1,000 rounds, so I’m pretty sure I’ve shot at least 900 rounds of this ammo already, and I would remember if I had issues like this before.

So, as far as I can tell, this was most likely good ammo stored badly.

Either way, I’m very happy with the barrel. While it did burst, it did so in as safe a way as possible and didn’t send any frag anywhere. Even with more rounds going down the pipe, nothing broke off. Huge props to Faxon for their barrel.

Faxon sent out a new barrel so I could finish this review, and I really appreciate it. The second barrel has performed wonderfully.


From barrel to buttstock, I’m loving this PCC. It’s light, it’s handy, and it shoots great. What started as my spare parts PCC has become one of my favorite guns to shoot.

If you’re building a PCC for yourself, I very highly recommend the KP-9 lower, the Cryptic Coating BCG, and the Faxon barrel. Start with a great base of parts like that, and the sky is the limit.

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1 Comment

  • Rotwieler13 says:

    My first AR I had my local gun store build me a 9mm I knew my pistol was going to be a 9mm only one ammo to buy great gun was cheap to shoot before FJB came along

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  • My first AR I had my local gun store build me a 9mm I knew my pistol was going to be a 9mm only one ammo to buy great gun was cheap to shoot before FJB came along

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