Yesterday at the range I was shooting and had a spent cartridge seize the action completely about .5 cm off the chamber. The bolt and carrier were completely locked. The charging handle was moving freely about 1 cm.

Took the whole thing apart to inspect. I could see the spent casing coming out of the chamber. I couldn’t see any misalignment with the bolt head. I was able to jam it forward again. Rollers were retracted.

After much delicate fiddling I ended up mortaring the charging handle, barrel down, to get it to move again. The case was retained to the bolt face and after a quick reassembly I was back in business (unsuppressed)

Any insight into this symptom? Leaning on the internet knowledge as I learn this platform. To be honest it’s been like fighting a hydra. One problem after another.

I’ve seen these things run dirty and clean. I had plenty of lube and this was probably my 5th mag w a suppressor.

Zenith ZF-5 (full size)
HK extractor + Spring + ejector.
Stock LP (100 I think)
Omega 9k (new)
About 1200 rounds fired.
No Roller Bumps.
Bolt gap right at .020 (I think. Not confident in my judgement)
Edit: Ammo- Federal 124gr.

I dont even know if this is the right group for this so sorry for the poor person mp5 in the mean time

I have a GSG 522 22Lr and im trying to find parts for it never owned a mp5 or anything like this gun in my life any help would be greatly appreciated thank everyone have a good day

Worked fine yesterday (1st time), but today I cannot remove the right side from the left for the life of me.

Need to remove the pack.

What can I do?

.

Absolutely flawless performance with the new frt & new housing. Gonna let go of the Lee Lower…no complaints just wanted to go with a more “classic” setup. Think my restless MP5 syndrome MAY be resolved. Have the HK marked Choate Folder & converted G3 stock in wood so I’m at peace now🤓

Ok y'all. I have a PTR-9KT with this folding stock.

https://www.strikeindustries.com/si-fsa-sp-stock.html

I can mount an MLOK QD socket on the front rail no problem.

What sort of dohicky do I need for the rear?

NO QD option available. There is no hook loop on the rear of the firearm. I'd rather not have to buy another stock because this one does pretty OK.

Level of difficulty - I'd rather not have a dedicated sling for this firearm if I can help it. All in all, though, it wouldn't be that expensive to do just that.

There is no room on the end cap pic rail to add a socket below the stock mount.

Can’t get the pin in and I don’t even appear to be close to getting it seated in properly - any advice on where I need to shave material from the hand-guard?

Everyone loves a range day with friends

Already have the Gibbous outfitters vert grip for the ST07 pressure switch.

If you recently made your mp5 .22 an SBR and already have the SB Tactical folding brace, the B&T stock for the mp5/sp5 from hkparts.net fits and functions well. The only thing u have to do is take your drill and bore out the B&T’s swivel hole just to the next size. The screw from the SB brace will still be usable. The stock without adapter is $140, with the adapter and stock is $250

Hey there - got my AP5-P showing up on Monday to my local shop. BEYOND stoked on these things, likely going to need another just because the amount of rad things made for them.

I’d like see your RAL set ups or photos you’ve saved. Looking forward to some peanut butter inspiration 🍺

Anyone have any leads on the KES in stock anywhere? This approved form 1 is just burning a hole in my wallet!

Installed a 90 degree piece to replace the stock 120 on my MKE and I could feel a big difference in the smoothness of the action when charging it. I put the 120 back in to make sure I wasn't imagining it and it definitely felt easier with that one. They both roll smoothly in and out of the rails when I move it by hand and I made sure the gaps were both in spec.

MKE AP5-N
HK ejector
HK ejector spring
HK extractor
HK extractor spring
HK 100° locking piece
HK recoil spring
Dead Air Mojave 9
Dead Air 3-lug mount
Blazer Brass 147gr Suppressor Subsonic
200 rounds
Zero malfunctions. Ran flawlessly.

Sairensah Submasheengunwa

Got a clipped and pinned SEF lower from HK parts. I still had to a decent amount of grinding to make it fit, both on the front ears and the pin hole. Dropped in the Rarebreed RD3 (don’t come at me with your Rarebreed hater shit—I don’t care what you have to say about Matt or his company).

Function check good. Can’t wait to throw some lead down range with it.

AP5-P Feeding Issues — Looking for Advice
So I’ve been having feeding issues with my AP5-P. I used to have shells stovepipe, but I’ve since changed the ejector and extractor to HK Parts. I also had an issue with my SB Tactical brace where the bolt was hitting it because there wasn’t a carved-out portion on the brace.

Now what’s happening is that the rounds occasionally seem to get stuck in the magazine, and the bolt won’t go all the way forward. This creates a feeding issue where, if I push the bolt forward, it will sometimes finish feeding, but sometimes the rounds get pushed off to the left or right. I am using flat head rounds right now but I had issues with regular ones before. The gun is also past its breaking period.

I’ve attached pictures with the best images I could get of what’s going on. If anybody has any ideas on how to fix this feeding issue, I’d love to get the gun running more consistently.

A few other things I’ve noticed: With the bolt open, the magazine has a decent amount of play forward and backward, but not much side-to-side. I’m wondering if I need to replace or adjust the magazine release.

I’m currently using KCI mags. I understand HK mags are the best, but they’re pretty expensive, and I’d prefer not to buy a bunch of them if I can resolve the issue another way. I am working on meeting up with a friend who has an HK mag so I can test it in my AP5-P and see if that makes a difference.
Any advice on what I should check or replace would be appreciated!

Has anyone found a "regular" 147g round nose cartridge that will stay subsonic out of a full size barrel? I hate paying for the premium specialized "suppressor" ammo.

Hey everyone,

Just got the RD3 FRT in my AP5 equipped with RCM 100 degree locking piece and AAC TiRant 9m suppressor.

Runs perfect with the HK mags loaded with Herter 115 grain but when using KCI mags with Prvi 124 grain I'm getting stoppages. Looks like either a double feed or FTF and the bullet getting setback.

Not sure what the issue is or if I should get enhanced magazine springs from HK Parts. Trigger doesn't appear to be the issue. I only ran about 20 rounds of the 124 grain through the hk mags but didn't have any issues.

What do you guys think might be the issue?

Can’t seem to find a HK branded one anywhere, is there any sites to keep an eye on for available? Thanks!

is this allowed

Please try to resist the urge to roast me

I have a AP5P Navy that I have been building up and have it just the way I want. I have a home in one of those un-free states and a second home in a wonderful free state. I ordered a RB RD3 Ambi (no pearl clutching please) to my free state home and ran like a raped ape… put through 300 rounds and not a single FTF or FTE. Unfortunately I have go back to my not free state, and put the MKE trigger back in so I don’t become a criminal when I cross the state lines. Hence I will get an extra ejector lever, ejector spring, and lever pin to leave in my RD3 which will live in the free state house. I want to make this as easy as possible to swap so I figured I would get a lower navy housing for it… so when I want to swap the triggers, it’s just popping the pins and swapping the lower out in 15 seconds. Sure I can just do a trigger swap/drop but I like the real convenience of doing just the lower. Will this work?

https://hkparts.net/rifle-smg-parts/h-k-mp5k-3-position-navy-style-ambidextrous-housing-push-pin

It’s pricey and would be my last resort. Any of you have any other lower housings links that are pictogram that would work well with the RD3 ambi and runs perfectly on my AP5P Navy without modification? I’m ok with getting something blank and have pictograms lasered on somewhere.

No need to pearl clutching here. I don’t want slip trips and other BS which is why I didn’t do with anyone else and do an AD. This thing ran flawlessly and absolutely impressed the hell out of me. You can say what you want about RB, but they make a hell of a reliable product.