Armory Sponsor
Posted: 7/31/2026 8:04:18 PM EDT
[Last Edit: desertmoon][Edited]
|
So, a good friend of mind purchased a MAC 5 recently. He brought it over, I looked it over but I am NOT an HK style guy so I have EXTREMELY limited knowledge on the MP 5s. Component-wise it seemed really decent. Anyhow, we look it over, clean and oil it, Check bolt gap, (.016", hammer down) check ejector height and activation (looked GREAT) and off to the range we went. Phew....what a complete jammo-matic. Terribly weak to non existent ejection. I was having "My m60 just somehow ate of a bunch of links in the middle of the night flashbacks" because this thing was just sucking the brass down into the nether regions of the receiver and that shit got ugly fast. When it would fire ( we tried 3 brands of 115 grain ammo ) the ejection was terribly weak. Most of the time, it wasn't even ejecting at all. Ya know, the visual cues of the gun were actually much nicer than I thought. I was expecting something between a Rossi 62 clone and a Rock Island arsenal gun but the components were very nicely made, it actually had a VERY nice trigger for an Hk Style gun. Almost as nice, though not as light, as my Hk 300. The gun felt, good. It felt smooth, It felt solid. Man, it ran like CRAP!!!! So, word to the wise. A lot of folks seem to have no trouble with these....but the ones who do. Eek. I am hoping MAC does him right. This thing is just bad. Oh, BTW: accurate as all get out. That alone made me almost want to take the risk of buying an alternate version...but I know better. I think. If anyone has any easy advice that might be an easy fix...well, I am sure he would appreciate it. I keep hearing and have even read here that swapping the extractor and spring for real deal HK extractors often turns these into really decent shooters. Again, the majority of the malfs were ejection related. Sometimes it chewed the brass but sometimes a stovepipe and sometimes, ( my favorite ) the brass would disappear into the back of the trigger group! (  ) Anyhow, here's a pic exactly like the case eating culprit:  Again, I am NOT an MP 5 or G3 or whatever guy....but I guess I had better learn. Thanks, Guys! ( P.S. IF I get one of these I am ponying up for the Hk. ) |
"Such predicaments! I must forge ahead!"
| MP5s and clones are designed to be broken in with 124gr NATO spec ammo (~500rds). My AP5 has been great after that period. The other factor you can try if hotter ammo doesn’t solve it is going to HK mags. If both of those don’t work it’s on to swapping the bolt components like the extractor. |
|
Originally Posted By bluedog82: MP5s and clones are designed to be broken in with 124gr NATO spec ammo (~500rds). My AP5 has been great after that period. The other factor you can try if hotter ammo doesn't solve it is going to HK mags. If both of those don't work it's on to swapping the bolt components like the extractor. I really wanted to try some 124 and I had plenty at home. I wish I would have grabbed it, Thank you for the advise!! I am going to pass it along. |
"Such predicaments! I must forge ahead!"
|
Originally Posted By osprey21: The MP-5 was designed around/for 124gr NATO loads. I sent my buddy a link for the hottest 124 ( seems to be Fiocchi ) grain ball ammo I could find and then a link for an Hk mag. This seems to be a good route. I am going to go back to working on Marlin lever guns and Colt REvolvers. Stuff I know I can do!!!! Still. I think I am going to start learning this platform. It's high time. Anymore help is still appreciated and thank you, guys, for the comments. |
"Such predicaments! I must forge ahead!"
|
Originally Posted By bluedog82: MP5s and clones are designed to be broken in with 124gr NATO spec ammo (~500rds). My AP5 has been great after that period. The other factor you can try if hotter ammo doesn’t solve it is going to HK mags. If both of those don’t work it’s on to swapping the bolt components like the extractor. Good advice |
|
Originally Posted By osprey21: The MP-5 was designed around/for 124gr NATO loads. The SAS adopted the MP5 before 1980 and made extensive use of their UK issue Mk 2z ammunition which was 115 grain. It's not like 124 grain ammo is a requirement. Around 1991 HK developed the Action 3 bolt group, which was specifically to correct feeding problems with RUAG's Action 3 ammunition, which utilized a 94 grain bullet. |
|
Originally Posted By KitBuilder: Yeah, that's what Germany issued at the time, but not all of NATO. The SAS adopted the MP5 before 1980 and made extensive use of their UK issue Mk 2z ammunition which was 115 grain. It's not like 124 grain ammo is a requirement. |
Now with more political fatigue.
|
Originally Posted By Goosemaster: Replace the extracter spring first, and possibility the extracter and ejector lever with HK parts. This and check to make sure the recoil rod is resting in the pocket/hole on the receiver cap. IF it is crooked and out of that pocket it could bind at the end of the bolt travel a bit and really weaken the extraction/ejection. I had that when I swapped out caps on a gun once - it had a small dimple for that pocket and the rod would move off of it - widened it with a drill bit just a little so it fit perfect and it fixed it. |
|
Originally Posted By cherenkov: This and check to make sure the recoil rod is resting in the pocket/hole on the receiver cap. IF it is crooked and out of that pocket it could bind at the end of the bolt travel a bit and really weaken the extraction/ejection. I had that when I swapped out caps on a gun once - it had a small dimple for that pocket and the rod would move off of it - widened it with a drill bit just a little so it fit perfect and it fixed it. |
"Such predicaments! I must forge ahead!"
|
Originally Posted By drobs: Note Winchester is really the only source for 124gr Nato ammo. It's sold in a white box as Nato or Flag box as Valor. It has 1200fps from the muzzle. Fiocchi's 124gr has 1150fps from the muzzle. |
"Such predicaments! I must forge ahead!"
|
Originally Posted By JoshNC: If you want an MP5, do yourself a favor and buy a German SP5 and/or SP5K-PDW. Skip the Turkish and paki copies. If they were the same price I’d buy the HK all day. But they’re not—like 1/3-1/2 the price. I’m very happy with my AP5 and I know a bunch of others who are too. |
|
Originally Posted By bluedog82: If they were the same price I’d buy the HK all day. But they’re not—like 1/3-1/2 the price. I’m very happy with my AP5 and I know a bunch of others who are too. "Just as good" lol Generally they work just as well. Sometimes the mag wells have some fore-and-aft wobble, which usually does not affect feeding. Welds and finish may not look as pretty. They're not like the old Special Weapons SW5 clones that actually sucked. I've seen photos of an SP5 delivered with rust in it. Never seen that from MKE. |
|
Originally Posted By bluedog82: If they were the same price I’d buy the HK all day. But they’re not—like 1/3-1/2 the price. I’m very happy with my AP5 and I know a bunch of others who are too. Originally Posted By KitBuilder: Yeah I have both and the MKE guns are almost as good. "Just as good" lol Generally they work just as well. Sometimes the mag wells have some fore-and-aft wobble, which usually does not affect feeding. Welds and finish may not look as pretty. They're not like the old Special Weapons SW5 clones that actually sucked. I've seen photos of an SP5 delivered with rust in it. Never seen that from MKE. I’d rather have fewer guns, but all quality without compromise. For me, buying German HK fits that bill. I’ve never had to tinker with German HK roller delays ever. They just work. I totally understand the desire to save money, that’s just not my philosophy when it comes to firearms. Quality over quantity is my mantra. |
|
Originally Posted By JoshNC: I’d rather have fewer guns, but all quality without compromise. For me, buying German HK fits that bill. I’ve never had to tinker with German HK roller delays ever. They just work. Originally Posted By JoshNC: I’d rather have fewer guns, but all quality without compromise. For me, buying German HK fits that bill. I’ve never had to tinker with German HK roller delays ever. They just work. (I understand that some people have.) Maybe I just got really lucky? I think maybe most MKE buyers are that lucky, but I don’t really know that for sure. I totally understand the desire to save money, that’s just not my philosophy when it comes to firearms. Quality over quantity is my mantra. Attached File Attached File Attached File |
|
Originally Posted By KitBuilder: I've never had to do any tinkering with my MKE firearms. (I understand that some people have.) Maybe I just got really lucky? I think maybe most MKE buyers are that lucky, but I don't really know that for sure. I like both. https://www.ar15.com/media/mediaFiles/13082/IMG_6760_JPG-1363014.JPG https://www.ar15.com/media/mediaFiles/13082/0E8D46AC-5C26-40D0-9365-3B1C175DAC5C_jpe-1417183.JPG https://www.ar15.com/media/mediaFiles/13082/D5BC4523-04AD-492F-8F1D-7D52F5F3D81C_jpe-2362714.JPG |
"Such predicaments! I must forge ahead!"
|
Originally Posted By xoldsmugglerx: Sounds like it could be the bolt gap is too little causing poor ejection. If you have feeler gauges, I'd try measuring it and compare it to the specs. If it is off, you could buy + or - rollers to adjust it. |
"Such predicaments! I must forge ahead!"
|
I went ahead and swapped in a German extractor and ejector although the MKE one my AP5 came with looked identical I also ran HK mags for awhile. It had some issues here and there but once it hit about 500 rounds it’s been solid I shoot whatever cheap 115 gr including steel cased and different cheaper mags and it runs and runs |
|
Originally Posted By glocktalk: I went ahead and swapped in a German extractor and ejector although the MKE one my AP5 came with looked identical I also ran HK mags for awhile. It had some issues here and there but once it hit about 500 rounds it’s been solid I shoot whatever cheap 115 gr including steel cased and different cheaper mags and it runs and runs HK ejectors and MKE ejectors are slightly different just look at cut on the face, HK’s are gen 3’s with MKE being gen 1 ‘s. I’ve not had any issues with my 3 MKE ejectors but have HK’s for spares. |
|
Dunno OP, sounded more like 'extraction' problem rather than 'ejection'. The 2 are not related to the same part. I would check the extractor spring as it is the most replaced item. Look up on Youtube on how to check. My Century Arms MKE AP5K functioned 100% out of the box, with Magtech 115 steel case, S&B 115 (NATO power rated), and Fed 115. Tried some 124 Magtech and Blazer just for grins, all functioned fine with the supplied MKE 30 rds mags. The only thing I did before going to the range for live testing - stripped the thing down, wiped off excess oil, reassembled to make sure things runs smoothly, that was it. Let MAC resolve the issue if you guys don't want to deal with it but replacing the extractor spring might be quicker DIY solution. https://hkparts.net/hk-rifle-smg-parts/hk-mp5-mp5k-replacement-parts-kit/?query_id=7c3f6f741cd2f54f076cb54a367b28c7 |
|
My experience is limited compared to others here. But I had some extraction and ejection issues to work through with my Cetme. First a weak extractor spring, they are cheap enough and take about 5 minutes to change. They are so cheap and easy to change that it’s worth it to rule them out as a problem. The extractor was noticeably harder to push with the new spring. Next my ejector wasn’t lined up with the groove in my bolt. This was causing the ejector to go under the bolt and push it up on the receiver and slowing it down significantly. I slightly bent the ejector to line it up. Next I stapled progressively finer grit sand paper to a paint stir stick and I sanded the rails until they were completely smooth. Then I gave everything g a good greasing. After this I was chucking the cases 20 feet and running reliably. |
| Try an HK mag or even load a round and then remove the mag and see if extraction and ejection improve. I saw 2 MAC5 mags that sat slightly high and caused issues. An HK mag ran beautifully. The MAC5 mags just needed to be filed a bit so that they sat lower on the mag catch and then the issues went away. This was with 115gr Winchester White Box in a MAC5 |
|
Originally Posted By osprey21: The MP-5 was designed around/for 124gr NATO loads. Repeated for emphasis. Failures reeked of weak ammo for that design. Check to see, I think S&B has NATO spec 124gr ammo at a reasonable price. That is what I'd try first. Oh, +1 to post count. 
|
Call the tune and let's dance; but beware that the devil is the piper and the tab for that soiree will be hell to pay.
Training&Trigger Time are more important than chasing a hardware Holy Grail
Training&Trigger Time are more important than chasing a hardware Holy Grail
| Again. Thank you for all of the replies. My buddy is gonna get either S&B or Winchester NATO and is ordering an extractor a couple of springs and an Hk mag. Then we start over. I told him everything I learned in this thread and I really can't thank you guys enough for your replies. |
"Such predicaments! I must forge ahead!"
Member
Joined:
Oct 2024
Posts:
593
EE: 100% (9)
USA
|
Lemme tell you mang That’s nothing compared to the issues of this Cohaire  It sat in a box under the stairs for over a decade. One day I dug it out and started grinding and beating on it lol. After surgery and the only thing left on it as Cohaire (the receiver) it runs like a raped FRT fed ape. Everything down to the roll pins holding the handle in the cocking tube support is German. For you I’d just replace with a German extractor and a silver (556) extractor spring. That’s fixed 95% of folks problems over the years in my experience. 
|
|
Originally Posted By HKH: Lemme tell you mang That's nothing compared to the issues of this Cohaire It sat in a box under the stairs for over a decade. One day I dug it out and started grinding and beating on it lol. After surgery and the only thing left on it as Cohaire (the receiver) it runs like a raped FRT fed ape. Everything down to the roll pins holding the handle in the cocking tube support is German. For you I'd just replace with a German extractor and a silver (556) extractor spring. That's fixed 95% of folks problems over the years in my experience. https://www.ar15.com/media/mediaFiles/99571/IMG_5467-3803102.jpg ...a Cohaire.... to WORK? I was proud of getting and Auto Ordnance 1911 to work....but THAT is an accomplishment. |
"Such predicaments! I must forge ahead!"
|
Originally Posted By desertmoon: You got..... ...a Cohaire.... to WORK? I was proud of getting and Auto Ordnance 1911 to work....but THAT is an accomplishment. Originally Posted By desertmoon: Originally Posted By HKH: Lemme tell you mang That's nothing compared to the issues of this Cohaire It sat in a box under the stairs for over a decade. One day I dug it out and started grinding and beating on it lol. After surgery and the only thing left on it as Cohaire (the receiver) it runs like a raped FRT fed ape. Everything down to the roll pins holding the handle in the cocking tube support is German. For you I'd just replace with a German extractor and a silver (556) extractor spring. That's fixed 95% of folks problems over the years in my experience. https://www.ar15.com/media/mediaFiles/99571/IMG_5467-3803102.jpg ...a Cohaire.... to WORK? I was proud of getting and Auto Ordnance 1911 to work....but THAT is an accomplishment. I have a Cohaire and a Special Wepunz. Both run…. |
|
Originally Posted By sdacbob: If you have an Academy sporting goods store where you live, they carry Monarch ammo as a store brand. They also have Monarch 124 gr NATO ammo and it is usually made in Turkey. It is pretty decent. Baby steps. |
"Such predicaments! I must forge ahead!"
| If it is having problem. Contact Military Armament Corp and get a RMA and shipping label for repair. Also are you running a SB brace on it? If so try running it without the brace and just the factory endcap. The SB brace on mine was to tight and caused malfunction like you are having. The Magpul brace and A2 stock work 100%. I current have about 1500 plus rounds down range after figuring this out. First I heard about SB brace problem was here from another person having problems with them on the SP5. |
Armory Sponsor