Estimated reading time: 14 minutes
I turned a PTR 9KT into the MP5K I spent years building in video games, then dumped thousands of rounds through it in the real world. The final running total hits $5,008.58, and yes, I would absolutely do it again.
Table of contents
- My PTR 9KT MP5K Build Started With an Obsession
- MP5 or MP5K? Why I Chose the Compact Route
- PTR 9KT: The American MP5K Clone I Built Around
- MP5K Handguard Setup: More Rail Space Without the Bulk
- Holosun SCRS: The Tiny Red Dot This MP5K Needed
- AB Suppressor F4: Tiny, Titanium, and Perfect for the MP5K
- Turning the PTR 9KT Into an SBR With a B&T Stock
- Fixing the PTR 9KT Trigger, With Another Upgrade in Mind
- Thousands of Rounds Later: This MP5K Is No Safe Queen
My PTR 9KT MP5K Build Started With an Obsession
If you’re a fan of the MP5 platform and its variations, we have this in common. This PTR 9KT MP5K build is my attempt to turn that obsession into the real thing. I am going to detail my own MP5K “build” because I love it so much. I hope that those who want to can use this as a guide to create something truly special for any gun owner. But be warned, this is a costly endeavor.
There are levels to an HK fan. Some build exact replicas from various military operations. Some marvel at the engineering design of various platforms. And some just admire the vibe. I’m probably a combination of the latter two. I’m not from the era that watched British SAS breach the Iranian Embassy while clad in ninja-like attire, brandishing the MP5 platform. In fact, I wasn’t even born yet. However, I grew up on the echoes of the MP5’s legendary legacy. I also find a certain respect for the design of the MP5’s roller-delayed operating system, specifically.
Before I was old enough to purchase a firearm, I was customizing the MP5 to my liking in video games. In fact, I’d bet any FPS video game fan from my generation had a loadout with a red tiger stripe, suppressed MP5 in COD 4. Now that same generation, myself included, is grown up and can spend our grown-up money on real guns. So here’s a rundown of how I recreated an iconic firearm from my virtual childhood in real life, as an adult.
MP5 or MP5K? Why I Chose the Compact Route
There is a myriad of MP5 variants. However, in my head, there are two MP5s: the MP5 and the MP5K. This may be a blasphemous statement to some, but please bear with me for the sake of simplicity.
Both of these have their positives and negatives. MP5 pros include better controllability and increased real estate for attachments. In contrast, the MP5K pros include a higher fire rate in full-auto or forced-reset semi-auto, easily fitting in a briefcase or backpack, lighter weight, and a more compact footprint when deployed in CQB.
Obviously, I think the pros for the MP5K outweigh those of the MP5. Naturally, I went this route when purchasing my platform.
PTR 9KT: The American MP5K Clone I Built Around
Ok… it’s not that simple. I want an MP5K, but how do I get one? Good luck getting one from HK themselves. Or, at least that was how it was at the time I was looking to purchase. HK’s own SP5K-PDW was released in 2020, while there was already a bunch of companies selling MP5K clones.
Many of these clones are very high quality and boast excellent reviews of reliability. And by “many,” I mean that. There are a lot of MP5 clone manufacturers. One such company is PTR. PTR gained my interest by being U.S.-based and by using authentic HK tooling in their manufacturing process.
Naturally, I chose to build my dream gun with the PTR 9KT, built on home turf in South Carolina. From this point forward, I’ll refer to this gun as an MP5K, but please keep in mind that it is an MP5K clone called the PTR 9KT.
This gun has a few specific features that I was looking for. First, it has a threaded, tri-lug barrel for suppressor compatibility. Second, it features a section of Picatinny rail for mounting optics without purchasing some weird adapter or claw mount, as you’d have to with many other MP5K options. And finally, the 9KT comes with a Picatinny adapter for mounting a folding brace until the gun can be SBR’d. Lord knows we are SBR-ing our MP5K in the future.
Build list:
PTR 9KT $1,989.00
Running total:
$1,989.00
MP5K Handguard Setup: More Rail Space Without the Bulk
To deal with the real estate issue for mounting attachments to the handguard, I chose to simply acquire a handguard that has a lot of mounting options. The handguard of choice is the Midwest Industries MP5K M-LOK handguard. This handguard provides two full-length M-LOK slots at the 5,6, and 7 o’clock positions. There is also one M-LOK slot located at the 2,3,9, and 10 o’clock positions. This provides 10 different mounting locations for lights, lasers, pressure switches, foregrips, and more.
Naturally, there is a myriad of options for all of these accessories. I knew I wanted a hand stop, a visible laser, and a light at the minimum. After scouring the web for inspiration, I found it at The Firearm Blog.
I copied Nicholas’ setup, choosing a green Viridian HS1 M-LOK Hand Stop with Integrated Laser Sight. This consolidates the laser and hand stop. I also used a SureFire Mini Scout Light Pro, paired with a Unity Tactical Unity Hot Button M-Lok. I linked these using the UE Scout Light Rear Cap. If I can ever afford night vision responsibly, this setup will change slightly to include an IR light and laser.
Build list:
PTR 9KT $1,989.00
Midwest Industries MP5K M-LOK Handguard: $131.95
Viridian HS1 M-LOK Hand Stop with Integrated Laser Sight: $149.00
Mini Scout Light Pro: $379.00
UE Scout Light Rear Cap: $79.00
Unity Tactical Unity Hot Button M-Lok: $108.00
Running total:
$2,835.95
Holosun SCRS: The Tiny Red Dot This MP5K Needed
Remember, one of the reasons I bought the PTR 9KT is because it had a Picatinny rail for mounting optics. This opens up literally endless options for optics. It makes sense to me to have an enclosed red dot on a riser. This narrows our options down significantly. Next, I want this optic to be relatively small to continue the overall theme of the MP5K build. With this consideration, I chose the Holosun SCRS.
The Holosun SCRS is available with a red or green multi-reticle or 2 MOA reticle option. It’s also solar-charging, has a manual and automatic brightness mode, 20,000 hours runtime, shake-awake, IP67 waterproof rating, and many more features. Basically, this micro red dot sight has everything going for it. Oh, and it comes with a riser and mounts to a Picatinny rail. Perfect.
Build list:
PTR 9KT $1,989.00
Midwest Industries MP5K M-LOK Handguard: $131.95
Viridian HS1 M-LOK Hand Stop with Integrated Laser Sight: $149.00
Mini Scout Light Pro: $379.00
UE Scout Light Rear Cap: $79.00
Unity Tactical Unity Hot Button M-Lok: $108.00
Holosun SCRS: $317.64
Running total:
$3,153.59
AB Suppressor F4: Tiny, Titanium, and Perfect for the MP5K
Because the 9KT has both direct thread and tri-lug mounting options for suppressors, I have nearly endless options available to choose from yet again. To narrow these options down, I had two criteria a suppressor had to meet: lightweight and short. At the time, the best 9mm suppressor that fit these criteria perfectly was the AB Suppressor F4. I would even say that it is still the best, even with sound suppression performance being thrown in as a consideration.
The AB Suppressor F4 is a fully titanium can with a 1/2×28 TPI direct thread mount. It’s also short, coming in at 4.9 inches long. This suppressor adds less than 4.5″ in overall length to my MP5K, suppressing it well. On top of this, it only weighs 4.5 ounces! When I first picked this suppressor up from my FFL, I had to open the box it came in to make sure it was even in there.
Build list:
PTR 9KT $1,989.00
Midwest Industries MP5K M-LOK Handguard: $131.95
Viridian HS1 M-LOK Hand Stop with Integrated Laser Sight: $149.00
Mini Scout Light Pro: $379.00
UE Scout Light Rear Cap: $79.00
Unity Tactical Unity Hot Button M-Lok: $108.00
Holosun SCRS: $317.64
AB Suppressor F4: $580.00 + $200 Tax Stamp
Running total:
$3,933.59
Turning the PTR 9KT Into an SBR With a B&T Stock
How can you own an MP5K and not convert it to an SBR? I couldn’t.
First, I applied for a Form 1 which makes it legal to convert your firearm to an SBR… well, partially. You also have to permanently mark the receiver with the required identifying information, among other things. If you’ve completed the legal jungle gym that is the SBR process, you know it was hard the first time, but easy once you know what to do. For a guideline on this process, check out this detailed how-to by National Gun Trusts.
As soon as the Form 1 was approved, I purchased a buttstock from B&T. I went with their BT-20155 polymer folding stock with adapter for the MP5. Buttstock options for the MP5K are basically split between collapsible and folding options. I like the look of the collapsible buttstock, but prefer the feel of the folding stock. Ultimately, ergonomics won and I chose this buttstock from B&T.
Build list:
PTR 9KT $1,989.00
Midwest Industries MP5K M-LOK Handguard: $131.95
Viridian HS1 M-LOK Hand Stop with Integrated Laser Sight: $149.00
Mini Scout Light Pro: $379.00
UE Scout Light Rear Cap: $79.00
Unity Tactical Unity Hot Button M-Lok: $108.00
Holosun SCRS: $317.64
AB Suppressor F4: $580.00 + $200 Tax Stamp
BT-20155: $325.00 + $200 Tax Stamp
Running total:
$4,458.59
Fixing the PTR 9KT Trigger, With Another Upgrade in Mind
The trigger that comes on the PTR 9KT is pretty abysmal. But it’s designed for a submachine gun, so I guess this is only natural. The last upgrade that I made to complete my MP5K build was swapping this trigger for something better. Currently, this means that I have a Timney HK MP5 Two-Stage Trigger installed. This trigger is crisp and light, allowing me to run it as fast as my trigger finger can move.
Still, this isn’t the final evolution of my MP5K. In the future, I want to supercharge my trigger finger speed with an FRT. There are a bunch of different options available for the MP5K, but they’re all very convoluted. Some approaches involve multiple aftermarket components. I won’t bother to mix and match this and that to find the right combination.
Instead, I will wait for a drop-in FRT trigger. Rare Breed currently offers one, but due to the political bull crap they are involved in, I don’t want to give them any of my hard-earned pennies. Instead, I am waiting for AS Designs to release their ARHK drop-in FRT for HK roller-delayed platforms.
The ARHK is described as a 3-position FRT. With this, my MP5K would have safe, semi- and “FRT” functionalities. AS Designs plans on these being available for purchase early in October of 2026.
Build list:
PTR 9KT $1,989.00
Midwest Industries MP5K M-LOK Handguard: $131.95
Viridian HS1 M-LOK Hand Stop with Integrated Laser Sight: $149.00
Mini Scout Light Pro: $379.00
UE Scout Light Rear Cap: $79.00
Unity Tactical Unity Hot Button M-LOK: $108.00
Holosun SCRS: $317.64
AB Suppressor F4: $580.00 + $200 Tax Stamp
BT-20155: $325.00 + $200 Tax Stamp
AS Designs ARHK: $549.99
Running total:
$5,008.58
Thousands of Rounds Later: This MP5K Is No Safe Queen
Yes, I have spent thousands recreating a childhood fantasy gun. I would also do it all over again. The MP5K legacy is timeless, and I know that this will always remain a favorite firearm of mine because of this.
Besides being a huge vibe, this PTR 9KT MP5K build is incredibly functional. It lives on my nightstand and would be a perfect self-defense weapon against anything that goes bump in the night. Through heavy use, I’ve proven this gun to be reliable and accurate as well as quiet and soft-recoiling.
I’ve shot thousands of rounds through this gun at the range. During this time, I’ve found that most bullet designs work flawlessly. However, the MP5 as a platform in general is known to have issues feeding truncated cone projectiles and some hollow point designs. I’ve noted that my PTR 9KT shares this flaw, failing to feed almost all truncated cone projectiles. However, I’ve found most hollow points to not cause issues.
Also, I’ve even taken this MP5K build into the competition shooting world of USPSA. For those who don’t know, USPSA involves running through a course of fire, shooting all targets as accurately and quickly as possible. During this time in the competitive shooting scene, I’ve learned that the proper reloading procedure for an MP5 is lengthy, cumbersome, and slow. Consequently, there are better platforms for this shooting sport, but I can promise if you show up with an MP5 to shoot regardless, everyone will be talking about you.
PTR 9KT MP5K Build Specs and Cost Snapshot
| Base Platform | PTR 9KT |
|---|---|
| Platform Type | MP5K clone |
| Suppressor Mounting | Threaded, tri-lug barrel |
| Optic Mounting | Picatinny rail |
| Handguard | Midwest Industries MP5K M-LOK Handguard |
| Optic | Holosun SCRS |
| Suppressor | AB Suppressor F4 |
| Suppressor Length | 4.9 inches |
| Suppressor Weight | 4.5 ounces |
| Stock | B&T BT-20155 |
| Current Trigger | Timney HK MP5 Two-Stage Trigger |
| Final Stated Running Total | $5,008.58 |
PTR 9KT MP5K Pros and Cons: Expensive, Addictive, Worth It
- Pros: Compact MP5K footprint, soft-recoiling roller-delayed system, strong suppressor compatibility, built-in Picatinny optic rail, ample accessory space with the Midwest Industries handguard, excellent shootability, and proven reliability through thousands of rounds.
- Cons: The build gets expensive fast, the factory trigger is pretty abysmal, some truncated cone projectiles fail to feed, and MP5 reloads are lengthy and cumbersome compared with better competition platforms.
The $5,008.58 Verdict: I’d Build This MP5K Again
That is the ridiculous beauty of this entire PTR 9KT MP5K build. It started with an iconic gun I knew from video games and the echoes of the MP5’s legendary reputation, then slowly turned into something I actually shoot, suppress, compete with, and keep close at hand.
Could I have spent less? Obviously. A lot less. But the point was never to assemble the cheapest possible roller-delayed 9mm. I wanted my MP5K, with the optic, light, laser, suppressor, stock, trigger, and overall vibe that made me want one in the first place. At a running total of $5,008.58, that childhood fantasy certainly wasn’t cheap. After thousands of rounds, I’d still do it all over again.
Related Reads from GunsAmerica Digest
- Taurus RPC Review: MP5 Feel Under $1,000
- SAINT Victor 9mm PDW Review: Tiny, Fast, Mean
- The Kuna: A Feisty New Sub-Gun From Springfield
Riley Baxter is a seasoned hunter, outdoorsman, and competitive shooter with deep roots in the backcountry. He has guided professionally for bears, bighorn sheep, and other big game across rugged terrain, bringing firsthand knowledge of what gear actually works in the field. When he’s not chasing game or running drills on the range, Riley is likely in the garage customizing his rifles, pistols, or backcountry kit.
A competitive pistol shooter and lifelong firearms enthusiast, Riley brings both precision and creativity to every piece of equipment he touches. Outside of the gun world, he works as a perfusionist in Montana, a vital role in heart surgery that demands attention to detail, critical thinking, and mental fortitude.
Experience:
– Professional Hunting Guide – Guided for bears, bighorn sheep, and more in some of the West’s toughest country.
– Competitive Shooter – Skilled USPSA pistol shooter with a passion for precision and performance under pressure.
– Custom Builder – Enjoys building and tuning firearms and equipment to meet the exact demands of the hunt or the range.
– Experienced Marksman – Experienced in long-range hunting and precision rifles to meet the demands of the terrain of the West.
– Montana-Based Perfusionist – Medical professional accustomed to making critical decisions in high-stakes environments.
I foresaw some purist rage and some opinion preaching here in the comments of this article, but this is so much better than expected.
We don’t have to agree Evan and that’s OK. I use a FosTech which does come with a 20 round drum magazine but that’s a little obnoxious to be carrying around the house so I have a five and 10 round magazine also. I don’t plan on spraying my house up should somebody come in here so I certainly don’t need a 30 round magazine. My second choice would be my HK SP5… NO light, lol.
The way I look at home defense is this… The number one reason to defend a home, is family. Family safety comes first. I don’t care if they’re currently in the process of stealing my electronics or furniture lol. I have insurance and I don’t get attached to material items. I do get attached to friends and family and they come first.
Keep in mind that during a home invasion, chances are the invader has the advantage over you. He hears a noise coming from you, he’s already in the house… He’s going to honker down and then he has the drop on you. Too many people wanna be the hero and kill their home invader when in all honesty the smartest thing to do for anyone that has not been in that situation before with no real training, is get everyone in one room, shut the door, and call the police with your weapon focused on that door. You will obviously be in a different part of the room than the rest of your family.
Some People think because they go out and buy an AR, train on the range… they’re all of a sudden experts in clearing their own home. The adrenaline rush you get in doing this is huge and if you don’t know how to handle that rush, your brain will not function properly. Taking classes etc. certainly does help especially if they’re using something to shoot back at you like “lipstick rounds“ or paintball.
Maybe I’m crazy but I just go with a quality build from the start so… I forked out the cash for my HK SP5. I put a claw Picatinny on the top and mounted an holographic with a 5X Magnifier for fun at 100 yards, a Dead Air Wolfman tri-lug mount and a retractable stock. And I sure in the hell didn’t waste $600-$800 on a HK retractable stock when I could get one just as good from Magpul for $110, at the time. Sometimes I think you guys like to brag about how much money you actually put into a weapon that weighs a ton and doesn’t fire any better than one that weighs 3 pounds less because we don’t have the kitchen sink hanging off of it. If you’re spending extra cash to replace parts to save a few ounces, then you’re a wee Cunt and should get your ass out from in front of the TV and go to the gym or get a real job.
I can’t think of a better way to let the bad guy know where I am in my house than to put a flashlight on my fucking home defense weapon. You’ve been living in mommy and daddy‘s house for how many years… and don’t know your way around it yet?
All the rest of that shit you guys put on your weapons is just gay. It’s like you’re going to hop into a 1980s action movie with Arnold and Sylvester or you spend too much time playing video games. These aren’t toys but they are practical if built right.
I’ll bet you this response will be Kristall approved!
This is Kristall and I approve this message!
This is the way!
I think a light is an absolute necessity for a home defense gun, unless you’re running night vision.
The reason is target identification. Are you shooting an intruder or your teenager who is sneaking in/out? If you’re gonna fire a shot at someone, you best be 100% sure that that someone needs to get shot.
Now, that light needs to be set up a certain way. You need a momentary pad, not an on/off switch. And you need to train with it so you don’t ND it – a light ND can give your position away.
Evan… I would love to agree with you, I really would. Target identification is obviously key but you should always know where your children are. My parents never went to sleep until all the kids were in the house. During a possible home invasion, in my opinion, the first thing I would do is check to see where everyone is so that I don’t accidentally shoot them because my wife or the oldest child will take everyone else into one room and that would be a plan that would already be set up. And your children should be aware of the dangers of sneaking in late at night. A simple call out is a lot safer than a light. I’m sure your kids would be made aware of the dangers of sneaking in late at night. Plus I’m sure there is a sound difference in someone unlocking the door versus someone kicking in the door or breaking a window.
I’ll give you this though… If you have a secondary position already set up so that when you flash that light you can move, under the cover of darkness, to that new position… I’ll give you the light lol.
We were trained by two of the best and the one thing that stuck out more than anything, was what to do with your light while clearing a building. It doesn’t go on your weapon it goes in your hand. And your hand is held out to the side because the first thing a bad guy is going to shoot at whoever or whatever is holding that light. I will always use and believe the number one home defense weapon is a shotgun but to each their own.
One of the things I tried to teach our tactical teams and convoy security teams is to avoid “what if’s”. I told them the training I’m giving you is to put you in the mindset of one or two situations you may run into. There are a million different scenarios in the field and I can’t cover all of them in class. Stay alert and think tactically… That’s all the advice I can ever give to anyone regarding a home invasion. I don’t know it all… Never claimed I did and I’m just one of a million people with an opinion.
I still disagree on most of this.
First, I think a shotgun is an abysmal home defense weapon for a number of reasons – ammunition capacity and manual of arms being the top two. My home defense weapon is a suppressed 12.7″ SBR in 5.56, with an EOTech and a Surefire Scout light.
In a home invasion scenario, assume you don’t have time to wrangle the whole family. You need to aggressively go and face the threat. And that’s where the light comes in. Once you have eyes on the presumed threat, hit it with the light. This not only allows you to properly identify the target, but it also gives you the tactical advantage of blinding/stunning the target.
The light is useful for clearing as well – in short bursts along with movement.
A light in the hand along with a gun in the other is far from ideal. You want to be ready to use that weapon, and a light in your off hand does not allow that.
Yes, teenagers should be taught to behave responsibly. That doesn’t mean they’ll actually do it. Teenagers are idiots, I know, I used to be one. I snuck in and out of my own house (and more than one girl’s house) enough times to know that.
But yeah, a white light is useful in tactical situations at night. We used them in the Marine Corps in Iraq. And you need to be 100% sure before you can ethically shoot at a person. The light both allows for this identification and can give you a tactical advantage when used properly.
Don’t confuse clearing a house in Iraq with clearing your own home. You know we didn’t really care about anyone else in that house that was hit with rounds because we knew where our own men were. Our ROE allowed that, depending where you were… Casualties of war.
Now let’s talk about this sneaking in the girls houses thing lol…
if its not a full auto gun & semi auto.then its not a MP5K
If I threw a bunch of el cheapo crap on my MP5 clone, I wouldn’t write an article bragging about it.
AB are the absolute worst silencers I’ve ever heard. Visible lasers are gay. That Holosun optic you put on there is lame. And you still put a B&T stock on it?
This build is retarded. Get rid of the laser, those are gay and for idiots. Get a Rugged Sub9 or a B&T Print-X, that AB can belongs in the trash. Put a real optic on there, an EOTech or an Aimpoint micro or something. And get a Rare Breed FRT, which should be the first thing you do in any MP5 build.
Let’s see your build?
Hey Dominic… How do you post pictures in the comment section? I’ll give ya a minute to think that over.
Evan, let’s see your build.
Mine isn’t complete. I have the FRT and Rugged Sub9, I got the classic VFG handguard from HK Parts. It’s still wearing a brace, I’m probably gonna put the B&T stock on it. I haven’t decided on optic yet, but knowing myself, it’s probably gonna be an EOTech. Not sure if I’m gonna put a light on it or not.
Definitely not putting gay nonsense like visible lasers on jt.
You’re the only other person I’ve heard/read that uses the word gay in that way, other than myself. It looks like it when I use it are absolutely hilarious and a female friend of mine howls every time I use it in that way. Well played!