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Posted: 8/6/2026 10:20:08 AM EDT
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Okay, I'm taking my first plunge into the FN 5.7x28mm world, the new Kel-Tec KP50...it simply intrigues me. With the jungle-magazine adapter, it has 100 rounds "on-board". It has a 9.6" barrel to maxmize velocity. I will suppress it and if I like the concept, I'll Form-1 it. Disadvantaes: Ammo prices kind of suck (but it's at least readily available) OEM P90 mags are unobtanium right now (I'll have a few KCI mags). It's a Kel-Tec: they're like a box of chocolates...you never know what you're going to get  So, while this is no HK MP7, does it kind of fill a similar role? What role does a 5.7mm PDW fit and does better than the dozen other PCCs/SBRs I have that are in 9mm? Do I really even need to make an excuse or find a role? ROCK6 |
"The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants" - Thomas Jefferson
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Well, it’s ugly as sin and a Keltec, so there’s that. As comparing to the MP7, the FN P90 and 5.7mm round and MP7 and the 4.6mm round were pretty much direct competitors, so yeah I’d say it’s a similar role as far as a PDW goes. As far as pros compared to 9mm, there’s mag capacity and ammo size and weight, plus a high velocity rifle profile bullet, which is a lot better out to longer ranges. The cons are ammo cost and most of the ammo being supersonic if you’re looking to run suppressed. I say, if you want it, go for it. |
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Originally Posted By willi3d: Well, it’s ugly as sin and a Keltec, so there’s that. Originally Posted By willi3d: Well, it’s ugly as sin and a Keltec, so there’s that. Well, that describes have of ARFCOM GD, but they keep coming back Originally Posted By willi3d: The cons are ammo cost and most of the ammo being supersonic if you’re looking to run suppressed. This, for me, is the biggest detractor. I don't even have the KP50 yet (should pick up next week) but I've been picking up a variety of ammo; that shit ain't cheap. You can find deals, but that's for range ammo. Getting serious defensive ammo is where it hurts. I'm stil intrigued enough to give it a shot as a concept. ROCK6 |
"The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants" - Thomas Jefferson
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Originally Posted By Cycolac: 18" OAL isn't that small of a package. That's a consideration, but since the P90 is 19.6" OAL (fixed stock SBR), so there is that. I think the 9.6" barrel helps maximize the 5.7x28 ballistics, so ti's a little bit of a trade off. ROCK6 |
"The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants" - Thomas Jefferson
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"The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants" - Thomas Jefferson
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Edited to add a few observations: Kel-Tec kind of missed the mark on their top cover. The sides should have had MLOK slots vice holes as that would at least have given some realistic attachment points for lights or lasers. The charging handle rails seem flimy to me. Maybe I'm just more used to the AR platform with a stiff charging handle but the Kel-Tec just seems wierd in that it will flex a little when charging. Break down is very simple and the barrel is (oddly) fixed. ROCK6 |
"The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants" - Thomas Jefferson
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Originally Posted By Taters: Did you need to do anything special to torque the FH on? I’m contemplating one of these and hadn’t seen how muzzle devices should be installed. No, just tightened up with a wrench by hand for the test. Griffin Armament (who I trust) says to use 35 foot-pounds for 1/2x28 muzzle devices. The only issue I need to confirm before I Rocksett the flash suppressor is that the KP50 barrel has as shoulder-spacer from when I took off the OEM flashsuppressor. No issues or extra holes in my suppressor, but Rocksetting it and confirm the shoulder spacer will make it more secure. ROCK6 |
"The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants" - Thomas Jefferson
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Originally Posted By Taters: Awesome, thanks! I haven’t laid hands on one, and was concerned about over torquing the barrel in the receiver or something like with an AR-style setup. Well, I did contact Kel-Tec and they actually have very fast-responding customer service. There's a barrel spacer/washer (not a crush washer) behind the OEM flash suppressor. I replaced the OEM flash suppressor with the titanium, short flash suppressor from Griffin Armament for use with their tapered suppressors. For now, I just left the spacer on it (thinking of it more as a flush shoulder) and hand tightened it down. Kel-Tec said not to worry and either use a crush washer (if needed) or the shoulder/spacer and torque to manufacturer's specs (being 35-foot pounds). Today, I'll get the GA FP Rocksett on and torque properly. I'll need to get a new GA suppressor dedicated to it...so that's on the future list. ROCK6 |
"The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants" - Thomas Jefferson
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Follow up. I want to get more rounds through this KP50, but it’s been flawless through the first couple hundred rounds. I swapped the optic mount (Holosun AEMS with AD QD mount) and re-zeroed it. I only have 25 yards in my backyard range, but it was drilling groups that could be covered by a quarter. Given the heat index temps of 107 degrees and 90+ percent humidity with the sun beating down on me. I should have my YHM Fat Cat at the end of the week and will so how that works on the KP50, but the Recce 5k is doing okay. Accuracy is proving much better than expected. When using the “jungle mag” setup, I do keep a cap on the underside magazine. I’ve heard that recoil, jolts or jarring can cause rounds to pop out. I haven’t had that issue, but I do keep a cap on it. It’s easy enough to pop it off when rotating/changing magazines. I put the KP50 solidly in the PCC category and while kinetic performance can be debated, I see this as a very effective 100-150 meter tool when it comes to accuracy. The longer (9.6”) barrel does maximize the performance of the 5.7mm. ROCK6 |
"The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants" - Thomas Jefferson
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