Grips for the MP5/HK33 and HK91/G3 rifles can be converted for use on MP5K-type weapons. As you can see in the photo above, a small circle appears at about 2:30 position on the larger hole for the pin when this is done. I used to wonder why and since I started offering converted grips for sale, I’ve had a few guys also ask me why this is the case.
Well, the short answer is that the steel reinforcing that is cast into the rear of the grip has different holes when an MP5K grip is made vs. the others. This allows the hole for the pin and the countersink for the head to not encounter another hole.
With the MP5/HK33 and HK91/G3 grips, the designers never planned for a hole to be made in that location and as a result, the newly drilled hole runs right into an anchor hole they have in the metal to allow the injection molding to adequate bond to it.
If you try to drill into one of these grips, the smaller hole will get cut open and then ride the flute of the drill upwards and make a mess. To compensate for this, an end mill must be used to do a plunge cut straight down. There must be careful workholding fixtures to keep the grip from moving. Trust me, I’ve trashed a bunch of grips by not making sure the grip was completely secure.
Despite those rear anchor holes being removed, the steel reinforcing is still held in place. While theoretically weaker, I have not heard of any real world cases where the the steel (it’s folded sheet metal really) has come lose due to separation from the surrounding polymer.
For people using converted grips, just insert your rear pin such that the retaining wire is on the shoulder and not in the hole. That’s really the only difference. Of course, like most grips, some final fitting may be required – by using a circular file to adjust the rear hole, filing the front locking plate or removing a bit of material off the back with a file or by sanding.
Summary
In short, purpose built MP5K grips have enough spacing between the rear metal strap’s anchor holes for the 6mm pin hole and 9.5mm countersink to be drilled. Other HK models do not use that same spacing so the tell tale partial hole appears at the 2:30 position. It’s purely cosmetic and just requires the user to insert the rear pin such that the locking wire rests on the normal shoulder of the hole and not the newly formed void.
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There are some things I like on MP5Ks and some things I don’t. I usually dislike the triggers but my MKE AP5-P has a fairly decent trigger as MP5 and MP5Ks go. My MKE also had a factory contoured grip. Of all the HK grips out there, the contoured is the one I like best but there is one I like even more – the “Magpul SL Grip for HK94, HK93, 91 and Semi Shelf Clones”. That one heck of a long product name – just remember the model – MAG1070-BLK.
A few months ago, I installed one on my Zenith ZF5-P and really liked it. Whereas the MKE has a contoured grip, the Zenith has a basic straight grip that is only slightly more ergonomic than a rounded rectangle. I’d read a few posts about guys converting over the Magpul grip, so I did the same. You know what? I realy like it.
Doing the Conversion
The Magpul SL grip wasn’t designed for use on a MP5K but what you need to do is pretty straight forward if you have the tools and at least some basic knowledge of locating holes to be drilled.
Let’s go over some basics – first off, the steel “tail” that sticks out of the Magpul will need to be cut off. I’d recommend using something like a hacksaw, reciprocating saw or a bandsaw. I have a metal cutting bandsaw so I used that. Please notice I did not list a Dremel or similar rotary tool with an abrasive wheel. They risk making the steel so hot that the plastic could be damaged.
Next, sand the tail end smooth. Take off as little material as possible as it will help you get a solid lockup.
As you may have noticed, many MP5K-type weapons, such as those from MKE and Zenith, use two small pins to retain the grip assembly – one in the front at the bottom and one in the top rear. With the semi shelf and a snug fit, you just need the single rear pin to hold the grip’s rear end up and in place.
The front of the grip has a plate that interfaces with the semi shelf on your MP5K. Magpul includes instructions for SP5 owners that they may need to remove a little material for a good fit and I would assume this extends to the SP5K but I don’t know this for sure. With both my MKE and Zenith, no adustment was needed.
In terms of locating the hole, take your current grip and measure backwards from the front locking plate to the center of the hole. Then, measure down from the top of the grip. Use these two measures to locate where you need to do your cutting and then setup your mill accordingly or at least a good drill press because all you are doing is plunge cuts.
Cutting the rear hole.
Critical: You must make an insert from hard wood, plastic, or aluminum. If you don’t, the walls of the grip will flex and your holes are going to be a mess. I learned this the hard way. The width left to right is about 7/8″ and then you can decide how you want to handle the vertical. I’d recommend surrounding the area where you want to make the cut. I run my insert the whole length of the inside top to provide a firm support both for the clamps and the plunge cuts. You don’t wany anything to flex.
The first step is to cut the reliefs where the pin goes. The head of the takedown pin is about 9-9.1mm wide. A 9.5mm cut doesn’t give you much room to adjust. 10mm is just a tad wider and gives you more room to adjust your cuts later with a circular file and not have the head unable to sit down in the recess. The reliefs need to be cut about 3mm deep.
Next is to cut the 6mm holes for the pins. I’d recommend against a drill bit as it might get squirrely on you – both in terms of deflection or the bit getting caught on one of the holes in the steel reinforcement. Get a 6mm carbide end mill, make sure your grip is held securely and do a plunge cut.
If you do use a drill press, check your runout. If you have more than 0.5mm on one side, you risk cutting to big of a hole. You want to be somewhere between 6.0 and 6.1mm. If you go too wide, the retaining wire may not get a good enough hold to keep the pin in place.
Cleaning Up
Use a fine file or diamond abrasive stick to remove all material left over from cutting inside the grip so you have a smooth surface.
It’s time to test fit the grip. It may go in great all by itself or you may need to adjust it just a tad with a circular file. I’d recommend a 6mm tapered circular file so you have a lot of control.
Note, test fitting the grip by itself is one thing. Doing it with the stock, brace or endcap in place is another. You may find further adjustments with the circular file are required. Also, you can make things fit sometimes by moving or tapping the grip or whatever is on the end around. The sheet metal of the receiver can flex and sometimes it gives you just enough alignment to push the pin on through. I often tap (not bang) them in with a small hammer with a non-marring head.
You want everything to be snug. You’ll find the front pin doesn’t matter if everything is tight. If you really want a front pin, you would need to make a custom pin given the width of the Magul’s front lower “ears”. It would also only be cosmetic because you would be inserting a steel pin into soft plastic that does not have a reinforcing plate.
The moral of the story is to keep the front-to-back length of the grip long so it is snug – again, don’t cut or sand off more of the black plastic than you must. Also, try to be as close as you can with the pin holes at least vertically. Because of how the grip is sandwiched between the mag well and whatever is on the rear, it’s not going anywhere. The rear pin is the final part to limit movement.
The Results
The MKE feels great. I will upgrade the selector the Magpul ESK but even with the stock MKE selector I like the feel more.
Summary
I hope this helps you out if you want to do this yourself. For folks who just want to do the final filing adjustments, we will converted Magpul grips for sale. Please click here to go to our store.
Here are the original Magpul grips in case you are looking for them:
Production Grip Comment
For our production grips. the holes are based on a new unissued German MP5K grip. Depending on a bunch of factors, the exact holes in the grip you get will vary a bit. Fitting will be required – front to back and the hole locations.
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If you are looking for an extended selector lever for your MP5 or MP5K, these are really nice.
I hate bad triggers and the worst triggers I have ever used were on HK MP5 and MP5K weapons. I have no idea of the design intent – maybe a real strong emphasis on avoiding an accidental discharge by having a long spongy pull and then a break somewhere around eight pounds. For someone who likes crisp triggers and a lighter pull, the HK triggers in general can be a rude awakening.
I recently picked up Zenith Firearms ZF5-P, which is a MP5K clone. Zenith Firearms is based in Afton, VA, and make their various rifles and pistols there. They used to import MKE clones from Turkey but severed ties and are actually making them here in the US.
I bought the ZF5-P for a few reasons – First, I got a good deal on it. That always helps. Second, I no longer had any form of an MP5 and kind of wanted to get back in. Third, and the subject of this story, I knew Timney made a well-regarded trigger pack for the MP5/MP5K. Fourth, I had an urge to tinker and needed a test platform.
Now Zenith makes a big deal that they machine their cartridge walls vs. bending sheet metal resulting in a better trigger. I was kind of curious to check that out as well.
For the rest of the article, I’ll just refer to the trigger as an MP5 trigger because the MP5 and MP5K share the same trigger pack. It’s the grip that differs.
The Zenith’s Original Trigger
Well, I was hoping for a good trigger out of the box because of Zenith machining the walls of their trigger pack but to be honest, it was just another MP5 trigger. I bought a new Century MKE AP5-P and its trigger was better than the Zenith’s also. It’s not that the Zenith’s trigger is bad – my point is that the unit I received was no better than any other MP5 trigger I’ve used.
I used a Wheeler “Professional Digital Trigger Pull Gauge” and did 10 pulls of the trigger after lubrication plus I had pulled the trigger maybe two dozen times since I bought it so there was a tad bit of wear in before testing. At any rate, the lightest pull was 7 pounds 5.9oz. The heaviest was 7 pounds 13.5 ounces and the average came in at 7 pounds 11.3 ounces. So, just shy of 7.75 or seven and three quarter pounds. Still long, creepy, spongy … pick the bad discriptor you like.
The Timney MP5 2-Stage Trigger
These triggers are compatible with SEF/ Semi-Auto trigger packs and their style of safety selector levers.
These triggers are NOT compatible with Ambi/Navy/FBI trigger packs or .22 clones, as they are different internally.
Timney provides clear installation instructions in the package plus they have the following video to help with the install.
Folks, that trigger is amazing. Here are pull test results: Minimum pull weight was 3 pounds 2.7 oz. Maximum was 4 pounds 0.1 ounce. The average was 3 pounds 10.3 oz.
I’d call it crisp and clean. Night and day better than the original Zenith trigger.
Range Time
My brother-in-law, nephew and I took the Zenith ZF5-P and a Century MKE AP5-P to the range. For an MP5, the MKE’s trigger is fairly decent but was seriously beaten by the Timney.
Summary
I have never hid my dislike of MP5 triggers – I genuinely don’t like them and the only good things I can say are that they are reliable and you’ll probably never have an accidental discharge.
The Timney trigger ranks as one of the best upgrades I have done to a firearm. If you want a better trigger for your MP5/MP5K, or a clone of them, then get the Timney trigger.
Note, I have to buy all of my parts – nothing here was paid for by sponsors, etc. I do make a small amount if you click on an ad and buy something but that is it. You’re getting my real opinion on stuff.
If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com. Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.
In the last post, I told you I bought an HK SP5K. It’s relatively heavy and begging for a brace. I don’t really feel the need to spend the money and wait to register it to be a Short Barreled Rifle (SBR) and there are actually a ton of arm brace options out there.
Option 1: The SBT5KA Brace
I have a SB Tactical SBT5A Brace on my POF-5 and really like it. I knew they made a version for the SP5K known as the SBT5KA but I was hoping for something different. Please note they are two different models of braces reflecting the different receiver end caps.
Option 2: The SOB Brace
Every time I write this product name – the “SOB” – down, I smile. SB Tactical has a ton of braces for the AR/M4 weapons family and they have evolved a ton away from the ugly original. The SOB has clean lines and I run one on my PTR PDWR. I think it looks good and has handled the .308 rounds from the PDWR just fine and feels solid too.
Needless to say, I was bummed. I had it completely installed only to find out that the guide rods on the SBPDW run right into the sides of the SP5K. Crud. I didn’t feel like figuring out all the changes that would be needed.
Installation was a breeze. Pull out the two small pins at the back, swap the old end-cap for the brace, push them together and reinsert the pins. I did make sure the recoil rod lined up and nothing was binding as I reassembled the unit.
I Did Clean and Lube The Internals
I should point out that when I removed the end cap, I went ahead and slid out the bolt group and lubricated everything. I applied Super Lube grease to the bolt body and Mobil 1 Synthetic 10w30 via a precision oiler to the rollers of the bolt and rotating surfaces. I also oiled the pins on the trigger pack while greasing the hammer face with Super Lube.
Summary
So you see I went with the SBT5KA brace. In the next post I will discuss handguards.
Note, I have to buy all of my parts – nothing here was paid for by sponsors, etc. I do make a small amount if you click on an ad and buy something but that is it. You’re getting my real opinion on stuff.
If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com. Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.