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Posted: 5/12/2026 7:55:02 PM EDT
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I know, it has two strikes against it right from the get-go; 1), It's KelTec. Lots of people hate on KT. I only have one, a P-17 I bought for my wife that works perfectly. But this one intrigues me, being the only one of it's kind. 2), 5.7x28mm ammo. I hear it's difficult to reload, expensive to buy the factory stuff, but the biggest fly in the ointment to me is - does it work? Not "does the milspec stuff work", that's a given or USSS wouldn't issue it. But is there civilian available ammo in the US that is actually effective? Sure, I could make it a simple range toy, but I like stuff that is useable for more than one thing - even my SASS pistol caliber lever action rifles, which will likely never be shot past the 15 yard SASS target distance, get sighted in for 50-100 yards...just in case. So, in conclusion I was curious if anyone here had any real-world experience with gun or caliber? I know about the Ft Hood shooting, was there something where a good guy used one? Not a burning desire that I must own one by 5 PM Friday...just curious. |
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Originally Posted By armoredman: I know, it has two strikes against it right from the get-go; 1), It's KelTec. Lots of people hate on KT. I only have one, a P-17 I bought for my wife that works perfectly. But this one intrigues me, being the only one of it's kind. 2), 5.7x28mm ammo. I hear it's difficult to reload, expensive to buy the factory stuff, but the biggest fly in the ointment to me is - does it work? Not "does the milspec stuff work", that's a given or USSS wouldn't issue it. But is there civilian available ammo in the US that is actually effective? Sure, I could make it a simple range toy, but I like stuff that is useable for more than one thing - even my SASS pistol caliber lever action rifles, which will likely never be shot past the 15 yard SASS target distance, get sighted in for 50-100 yards...just in case. So, in conclusion I was curious if anyone here had any real-world experience with gun or caliber? I know about the Ft Hood shooting, was there something where a good guy used one? Not a burning desire that I must own one by 5 PM Friday...just curious. 2. It's just like reloading any bottleneck cartridge. Apply more CARE To neck prep (ie good chamfer) and wash the brass in water/simple green, and stop thinking you need to remove it. Too many people spend way too much time removing the coating thinking "its only for the P90 mag", when in reality it's because the case has like no taper and it's needed for function in almost all 5.7 guns except maybe the M*P 57 and DBX. You can't get violent fragmentation in 5.7 and reach penetration depths of 12". You can get to 12"+ with Hornady Black or a Vmax loaded to around 1800 fps (IE no SS197, Fiocchi HyperFormance). That type of expansion is basically on par with mid to upper 9mm JHP. If you want better wounding then that with the ability to pop barriers, you'll want a tumbling round. That's where copper solids come in handy in 5.7 but unfortunately only smaller loaders make loads. Elite Ammo, T6B, T7B, Devastator 2.0, 3.0. Vanguard Outfitters Black Dragon Fang. All of those will tumble, bring a bit of velocity (over 2000 fps from the pistols) and provide 12"+ of penetration. |
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Originally Posted By Buffman_LT1: 1. Keltec's various 5.7 designs are designed around operating SS197 or other weaker 40gr loadings. Running things like Hornady Black or SS195 or SS198LF will show pressure signs that other designs don't do. You can mitigate this in the Sub 2000 by using the heavy bolt weight. The P50 was the worst and I imagine the operating mech on the KP50 isn't different. I helped mitigate the risk on the P50 by going to the ST50 and using a heavy AR-15 hammer, but it still shows pressure sign with factory ammo. The PR57 seems better about this, but it also has a 4" barrel and the ballistcs are poor. You need Elite Ammo's S4M to get the same velocity that SS198LF can get from the 5.2" rock. 2. It's just like reloading any bottleneck cartridge. Apply more CARE To neck prep (ie good chamfer) and wash the brass in water/simple green, and stop thinking you need to remove it. Too many people spend way too much time removing the coating thinking "its only for the P90 mag", when in reality it's because the case has like no taper and it's needed for function in almost all 5.7 guns except maybe the M*P 57 and DBX. You can't get violent fragmentation in 5.7 and reach penetration depths of 12". You can get to 12"+ with Hornady Black or a Vmax loaded to around 1800 fps (IE no SS197, Fiocchi HyperFormance). That type of expansion is basically on par with mid to upper 9mm JHP. If you want better wounding then that with the ability to pop barriers, you'll want a tumbling round. That's where copper solids come in handy in 5.7 but unfortunately only smaller loaders make loads. Elite Ammo, T6B, T7B, Devastator 2.0, 3.0. Vanguard Outfitters Black Dragon Fang. All of those will tumble, bring a bit of velocity (over 2000 fps from the pistols) and provide 12"+ of penetration. Another thanks for the wealth of info. |
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I have the earlier, slightly funny looking version, but it's the same receiver and operating system. They don't seem to have the old one on their web page any more. It's been very reliable for me. I like it, but I like weird guns. I also reload for it. The biggest caveat in my opinion is that because of the tiny case volume, very small variations in powder drop give a pretty drastic variation in velocity from shot to shot. I use a Dillon 550, and I'm thinking about getting a powder trickler to keep them more consistent (I'm not chasing any performance milestones, just trying to keep my loads safe, reliable and consistent). Projectiles are 5.56, and you can load any projectiles 55 grain and lighter. 40 grain projos are what I seem to load the most of. 55 grain has to be subsonic. If you try to load them too hot, it will go out of battery. Get one. You'll have fun with it. |
"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 Buffman_LT1: Can you show me a picture of the hammer assembly they are using and the pictures of the spent cases of primers from the gun? @Buffman_LT1, will do later this afternoon, I'll @ you when I get them posted. 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 Buffman_LT1: Can you show me a picture of the hammer assembly they are using and the pictures of the spent cases of primers from the gun? @Buffman_LT1, here you go and I appreciate your assessment! The cartridge was dirty from suppression. This this is stupid simple, almost reminds me a compact Sten Gun operationally          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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Thank you, that was really what I was looking for, might be a great truck PDW if the ammo can be counted on for stopping power. I VERY much appreciate the detailed response and excellent photos, thank you! Does anyone know which commercially civilian legal ammo is considered decent SD ammo and what reputation it might have? |
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Originally Posted By armoredman: Thank you, that was really what I was looking for, might be a great truck PDW if the ammo can be counted on for stopping power. I VERY much appreciate the detailed response and excellent photos, thank you! Does anyone know which commercially civilian legal ammo is considered decent SD ammo and what reputation it might have? @Buffman_LT1 is our resident expert. Here's a good run down on page one by him: https://www.ar15.com/forums/Handguns/5-7x28-Love-or-Hate-/4-219652/ 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 armoredman: Thank you, that was really what I was looking for, might be a great truck PDW if the ammo can be counted on for stopping power. I VERY much appreciate the detailed response and excellent photos, thank you! Does anyone know which commercially civilian legal ammo is considered decent SD ammo and what reputation it might have? Originally Posted By armoredman: Thank you, that was really what I was looking for, might be a great truck PDW if the ammo can be counted on for stopping power. I VERY much appreciate the detailed response and excellent photos, thank you! Does anyone know which commercially civilian legal ammo is considered decent SD ammo and what reputation it might have? @Buffman_LT1 is our resident expert. Here's a good run down on page one by him: https://www.ar15.com/forums/Handguns/5-7x28-Love-or-Hate-/4-219652/ Just adding that stopping power is an interesting topic with the 5.7x28mm. The more velocity the better but you also need to figure out if you want penetration or expansion (in general terms). I don't see it as some great threat stopping offensive weapon but more as a PDW that can help get you out of a sticky situation. I'm sure it's effective (some evidence in real-world shootings) much like the M1 Carbine but its role seems more aligned to PDW than fighting tool. Originally Posted By Buffman_LT1: Thanks. if possible to find some of the 198 Brass I'd appreciate some pics of that. Those will have green primer sealer and 3 stake crimp As soon as I took the pics and saw the box of 198LF sitting there, I knew you would ask based on your concerns of the P50 I'll get a couple rounds shot off and take a pic of the brass this afternoon. How badly was that brass from the P50? ROCK6 |
"The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants" - Thomas Jefferson
"The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants" - Thomas Jefferson
Those look objectively better than the P50. There's still an ejector mark, but the primers don't look like this: 5.7x28mm Brass from P50 T&E by Buffman RANGE, on Flickr |
| Dang, I am so very happy that none of my fired brass out of my PS90 look like that. I'n currently on 3 reloadings on FN brass. FWIW: FN factory ammo was absolute CRAP. Wildly variable MV and report. A couple of rounds would not cycle the action. |
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Originally Posted By bbqncigars: Dang, I am so very happy that none of my fired brass out of my PS90 look like that. I'n currently on 3 reloadings on FN brass. FWIW: FN factory ammo was absolute CRAP. Wildly variable MV and report. A couple of rounds would not cycle the action. Originally Posted By bbqncigars: Dang, I am so very happy that none of my fired brass out of my PS90 look like that. I'n currently on 3 reloadings on FN brass. FWIW: FN factory ammo was absolute CRAP. Wildly variable MV and report. A couple of rounds would not cycle the action. My ammo? It was going on about 100 rounds suppressed, so it was pretty dirty coming out. Originally Posted By Truck_Norris: So you're saying you're buy-curious? Yep. I was honestly very intrigued by the design and mildly interested in 5.7. I'm not a huge fan of Kel-Tec minus a few of their designs, but this one is definitely different...in a good way. I like the PDW concept, and this fits the role pretty good. 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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