Gunsmithing MP5 clone questions/help

[jMarine]

Is there a knowledgeable mp5 guru on here that can help me? I know zilch about this weapon system except what I have been learning over the past few weeks watching various videos and reading other forums.

I recently picked up an AP5 and the first range session with it I had no issues. Everything seemed to work fine. I shot around 300 rounds. Even at home, larping around in my workshop pretending to be John McClaine doing numerous “HK slaps,” everything seemed to be fine. I go on my next trip to the range 2 weeks or so later, and at first everything seemed fine. At some point I ran the gun dry, attempted to fire, got a click, went to pull the cocking lever back and it made it about 1/2in and got SUPER tight. Like I had to brace it against my body to be able to cock it. This was consistent every time I ran the gun dry and even after the first time this occurred, simply racking the charging handle seemed more difficult than when I bought it.

Now I’ve read several other forums from other people who had a similar problem and it seems the consensus was that there could be an alignment issue. However, if there was an alignment issue, wouldn’t it have been a problem from the get go? Or did shooting it several hundred times exacerbate the issue?

I’m just looking for solutions to remedy it. I’ve field stripped it and checked various parts and the FCG. The charging handle seems to be difficult even when disassembled. Any thoughts what it could be? Can the cocking support break/crack and cause this?

 

[biffj]

You may have something jammed into the cocking tube that is dragging the cocking piece. Its not uncommon.
You could also have a lot of goop gumming up the works and after sitting a few days it solidifies a bit and makes things tough to run. My bet is on crap in the cocking tube. It could even be the retaining pin that holds the handle to the cocking piece.

What ammo are you running, this is a key question. Also, what mags? The system is pretty simple but the variation between makers and even between production runs can be amazingly wide.

Frank

 

[jMarine]

You may have something jammed into the cocking tube that is dragging the cocking piece. Its not uncommon.
You could also have a lot of goop gumming up the works and after sitting a few days it solidifies a bit and makes things tough to run. My bet is on crap in the cocking tube. It could even be the retaining pin that holds the handle to the cocking piece.

What ammo are you running, this is a key question. Also, what mags? The system is pretty simple but the variation between makers and even between production runs can be amazingly wide.

Frank

The first range session was blazer and I beleive some S&B. Second time to the range was just some Winchester white box. I only have the MKE mags that came with it.

Should I remove the cocking lever and pull the cocking support?

 

[dttheliman]

https://www.tiropratico.com/manuali-pdf/2015-H/Hk Mp5 ARmorers Manual.pdf may help you - there is probably as mentioned before shit jamming up everything - they like to be wet and clean. And just because MP5's everything

 

[jMarine]

I disassembled it again to inspect if anything was in the raceway of the cocking support and it appears to be clear. In the process I discovered it was extremely difficult to remove the cocking support like it was jammed or something. I had to use a a punch to stick in the slot the that the cocking lever travels into continue pushing the cocking support backwards past whatever was causing it to bind up.

Looking inside of the tube it appears that the welds could be ground down some more. But I’m not sure what amount of visible weld is acceptable since I am new to this platform.

Is it possible for a cocking support to become bent any and cuause it bind inside of the tube at some points?

I have a good video of how it’s binding in some spots during its rotation while trying to cock it. And how it is “free footing” and moves freely.

It’s so odd that it seemed totally fine and then all of a sudden it’s not.

 

[biffj]

it is quite possible to bend the tube and bind up the system. Maybe in your slap and shoot drills you dinged something. That is what you need to determine. You can use a sharpie or other marker to color the cocking piece. Put it back together and move it a few times, then look it over to see where the sharpie is worn off. Once you know that you can look at the part of the tube that is dragging. It could be a weld or a dent or? Since we can't see or handle it the diagnosis is up to you.
Check the handle itself as well. Make sure it moves freely in the slot. Make sure the spring isn't slipping out of place and catching between the handle and the slot and so on.

Frank

 

[jMarine]

Here are some pics for now. I’ll try and get more later when I fart with it some more. I wish there was a way to post a video on here

 

[dttheliman]

Here are some pics for now. I’ll try and get more later when I fart with it some more. I wish there was a way to post a video on here

That tube looks like a rat chewed it out , original MP5 stub pic below with dog hair to compare

 

[Evintos]

Remove the cocking tube end cap, check to see if you have a spacer, if so, remove spacer and then check for concentricity and check for binding. If it no longer binds, leave spacer out, it's not required and reinstall cocking tube end cap.

 

[jMarine]

That tube looks like a rat chewed it out , original MP5 stub pic below with dog hair to compare
View attachment 8162706

Haha yeah it looks a little rough on the inside. I wish I had better knowledge about inspecting these forearms prior to buying it so I could’ve thoroughly inspected it the gun store

 

[jMarine]

Remove the cocking tube end cap, check to see if you have a spacer, if so, remove spacer and then check for concentricity and check for binding. If it no longer binds, leave spacer out, it's not required and reinstall cocking tube end cap.

I removed the end cap and did see a spacer. How is this removed?

 

[Evintos]

I removed the end cap and did see a spacer. How is this removed?

Tilt muzzle down and give the cocking tube a couple of smacks or jiggle it free. If it doesn't fall out on its own, you'll have to push it out from the other end. Edit - with the cocking tube support removed.

 

[jMarine]

Tilt muzzle down and give the cocking tube a couple of smacks or jiggle it free. If it doesn't fall out on its own, you'll have to push it out from the other end. Edit - with the cocking tube support removed.

Yeah I quickly figured out it was just sitting there. So I did this. The cocking tube is off centered a bit but it definitely freed it up A LOT. But it is still sticking slightly in one area. Could this just be a break-in issue? It’s definitely way better than it was!!

 

[Evintos]

Yeah I quickly figured out it was just sitting there. So I did this. The cocking tube is off centered a bit but it definitely freed it up A LOT. But it is still sticking slightly in one area. Could this just be a break-in issue? It’s definitely way better than it was!!

Yeah it's gonna be a partial break in and partially because the cocking tube is not welded concentrically. It's not an issue if it's slightly crooked and it'll break in eventually.

Edit - the plus side of removing the spacer is free floating the barrel.

 

[jMarine]

Yeah it's gonna be a partial break in and partially because the cocking tube is not welded concentrically. It's not an issue if it's slightly crooked and it'll break in eventually.

Edit - the plus side of removing the spacer is free floating the barrel.

Awesome! This helped me out a lot. I put it all back together and it cycles just fine after dry firing. I’m glad it was a simple fix. I was concerned I was going to have to send it off to get worked on

 

[Nik H]

Is there a knowledgeable mp5 guru on here that can help me? I know zilch about this weapon system except what I have been learning over the past few weeks watching various videos and reading other forums.

I recently picked up an AP5 and the first range session with it I had no issues. Everything seemed to work fine. I shot around 300 rounds. Even at home, larping around in my workshop pretending to be John McClaine doing numerous “HK slaps,” everything seemed to be fine. I go on my next trip to the range 2 weeks or so later, and at first everything seemed fine. At some point I ran the gun dry, attempted to fire, got a click, went to pull the cocking lever back and it made it about 1/2in and got SUPER tight. Like I had to brace it against my body to be able to cock it. This was consistent every time I ran the gun dry and even after the first time this occurred, simply racking the charging handle seemed more difficult than when I bought it.

Now I’ve read several other forums from other people who had a similar problem and it seems the consensus was that there could be an alignment issue. However, if there was an alignment issue, wouldn’t it have been a problem from the get go? Or did shooting it several hundred times exacerbate the issue?

I’m just looking for solutions to remedy it. I’ve field stripped it and checked various parts and the FCG. The charging handle seems to be difficult even when disassembled. Any thoughts what it could be? Can the cocking support break/crack and cause this?

Have you tried posting this on HKPRO. Link is here.

Like Sniper's Hide but for HK stuff.

I have a couple of HK SP89s. I have fired over 7,000 rounds out of it. Never had this happen.

Have you taken it apart and looked at the bolt carrier? They like lube to keep them happy but not after 300 rounds

 

[biffj]

It does look like the welds on the right side are rubbing from your pics. Obviously we can't see the left side but chances are they're dragging too. With the spacer removed the tube can bend back to its resting position and you're likely clearing the welds a bit. If you can get a cartridge roll sander and put an extension on it you can get in there and clean it up a bit. Don't go overboard. All you need is for the cocking handle to be free enough to function. As to whether it will wear in its up to you. Most of us don't run the cocking handle enough to wear parts in but some folks do. If you do a lot of drills you may get it done. You can also oil the crap out of everything. It will help too but with the roller delay guns it gets messy.

Frank

 

[jMarine]

Have you tried posting this on HKPRO. Link is here.

Like Sniper's Hide but for HK stuff.

I have a couple of HK SP89s. I have fired over 7,000 rounds out of it. Never had this happen.

Have you taken it apart and looked at the bolt carrier? They like lube to keep them happy but not after 300 rounds

I haven’t posted on there, I don’t have an account. Maybe I oughta join over there as well now that I have one of these things

 

[biffj]

HK pro has a lot of great info but the site can be a little snobby. Since your mp5 isn't really an HK some folks get weird. I got banned for saying that registered sear guns were not original MP5's but rather semi's converted to select fire. Some folks are a little sensitive, or were a few years back. Maybe with the influx of more clones they're a bit less so....its worth a try for the info.

Frank

 

[Nik H]

HK pro has a lot of great info but the site can be a little snobby. Since your mp5 isn't really an HK some folks get weird. I got banned for saying that registered sear guns were not original MP5's but rather semi's converted to select fire. Some folks are a little sensitive, or were a few years back. Maybe with the influx of more clones they're a bit less so....its worth a try for the info.

Frank

A lot has changed and they are a bit more tolerant of clones these days.

I don't post much there but it is without a doubt the best place for information relating to HK (real or clones).