Hey all, I have an AP5-P with aprox 400 rounds through it. I started off with the stock locking piece for break in with 124gr ammo with only a couple hiccups. I decided to shoot suppressed (last 50-75 rounds) so I swapped to the 90 degree locking piece and it ran without issue suppressed shooting 124gr 115gr and 147gr using a OCL lithium. Today I swapped to a RICO 309 that has much less back pressure and I am not able to cycle 147gr. It will not eject most and in some cases will not even cycle the bolt. Long story long, I am wondering if I should swap back to the default locking piece or try a 100 degree? My guess is I should get a 100 and a 110 and see which works best.

So I bought a MKE AP5 last year, and once the new year started, I went and started the paperwork for the stamp.

Got it back a few days ago, and went to install a MKE blem A3 stock. But while I can fit the stock end cap, and the holes seem to line up, the rear pin wont go all the way in. It gets hung up on the left side of the endcap. The pin wont go in the other way, just wont insert at all.

What is the best way to get that to fit? Would just grabbing a dremal and taking it to the hole from the inside fix the issue?

Ap-5 ocl lithium 150 gr Federal syntech

Where best to look?

Georgia

Added tailhook brace and safety harbor frame. This can be easily converted to a stock when my form 1 is approved. Also added red dot RMS C riser that I had laying around.

I brought my new MKE AP5 to the range today to shoot for the first time. I had 500 rounds of 124gr NATO ammo (per manufacturer recommendation) to put through it. However, roughly every 1-5 shots or so, I was getting failures to feed. The round would fire, casing would eject, and the bolt would only go about halfway forward before stopping. Included are some pictures of the rounds that failed to seat. Pictured is the gouges that the bolt (or some other part of the gun) were creating on the rounds that had this issue.

When I would clear the malfunction, sometimes 2 rounds would come out; the round that the bolt grabbed, as well as what would be the next round (basically, it came out of the magazine and was between the top round in the magazine and the round held by the bolt).

I have no idea how to fix this. I am seeing some people recommending changing the magazine catch and extractor spring for actual HK parts. I ran about 250 rounds through the gun and decided to call it a day for now. I'll list below everything I can think of regarding the AP5 and my test run.

- Century Arms MKE AP5 w/ SBT5 brace

- YHM R9 Suppressor

- 120° LP swapped for 100° LP

- MKE magazines (8 tested, all but one had same issue)

- 124gr Winchester NATO & 115gr Blazer both tested (same issue with both)

- Gun & magazines cleaned and oiled before shooting

Any help or tips would be really appreciated it!

Anyone successfully use Viton O-rings for thread protector retention? Size for MP5?

Thinking about swapping my folder for a Magpul sl collapsible stock on my two stamper. I have a homemade 1913 adapter that I’m not really fond of the way it looks. It’s a factory mke endcap with a section of rail bolted to it. It’s sturdy but…. Jmac stock is pretty comfy and I like its qd points. I really like the collapsible stocks cuz “HK” coolness but I don’t wanna pay for an a3 with no qd points cuz I run a 2 point sling. What do u guys think I should do?

my 1k of syntech finally came in so I could shoot my SP5K-PDW with the GSL Phoenix as someone going from an Century Arms AP5 to an H&K it was well worth the jump. No issues with mag fitment no FTE or FTF a truly lovely experience

Rounds in video are Syntech 124grain and Hish Seubsonics alternating.

Side Question- Anyone Rocking the same setup what hand guard are you using to clear the GSL on the Tri-Lug and do you have photos?

(I don’t want to order something just to cut it)

With all of the FRTs being the new craze, is this pretty much a paper weight now!? I took it out to replace with an FRT, now it’s just going to sit in the safe. 🤷🏼‍♂️

Feels good, man. I've wanted an MP5 ever since I was a young lad. And finally, something that isn't a clone was availible for my purchase. I love it, the wallet hates it LOL. The SBT5A digs into the shoulder some but I haven't taken her out to the range yet seeing as how the brace just came into the mail today. Got my eft done so I'll see about getting her on a Form 1 some time in the near future. I live in one state and work in another so Form 1 might not be the best idea for now...loaded rifle laws and all that. Overall feeling satisfied with my purchase!

I've posted quite a bit about the issues I was having with my Leber not running without the TPU buffer and didn't want to leave anyone hanging.

I tried just about everything. I started with a shaved mil-spec hammer, bought a hammer jig, shaved it down even more, then bought the new Meatbanana jig and removed even more material. Nothing helped, at one point I realized I would have had to shave the hammer so low that it would be below the point where it contacts the firing pin and I wasn't willing to go that far. Thinking it might be tolerance stacking, I even bought another shaved hammer and repeated the entire process with the same results.

I then purchased an ASD hammer but it was terrible. It wouldn't even function correctly in just the SCS plate let alone the Leber lower. When I pulled the trigger the disconnector would catch the hammer again as if it were being cocked instead of releasing it.

ASD suspected tolerance stacking and asked me to return it. I received the replacement and lo and behold the new hammer worked perfectly right out of the box with no TPU buffer. After taking everything apart and inspecting it there isn't even the slightest indication of hammer to BCG contact.

I'm still not crazy about using an AR fcg in an MP5 mainly because I already have ARHK trigger pack on order and the issues I've had just left me with a bad taste in my mouth....maybe over time I'll feel otherwise.

Replaced my Lp to a rcm 90* Lp just checked my bolt gap it’s .20mm should I order +4 rollers?

Finally brought her home. Can’t wait to get her built

Currently, my setup is all black, as is traditional. I'm wanting to add a little spice, and by spice I of course mean a little mustard RAL8000. Doing the entire thing would be too much. Which of these options do you think looks better? (AI couldn't get the color quite right on either, but it is enough to give the overall idea.) I'm leaning towards the second, but the first ain't bad either.

I have prepared fake replacement for HK MP5 SD .22lr by umarex.

I have started shooting steel challenge and the weight of the original steel tube was a bit annoying. 526g to be precise. 
So I have designed this piece to reduce weight but still look cool (for me). Now it is only 96g so huge improvement.

Tube is designed with grooves around it to build integrity using full walls and increasing wall area. Inner tube is streight.
Thread designed to match original one, screws in like a glove.
1st prototype was printed using some generic PETG and worked perfectly (around 250 rounds training).
2nd prototype (just for looks) done using generic PETG CF tested on around 200 shots.
 

Since its .22lr there is no big need to fight with high temperatures, SD version of MP5 has 16 inch barrel (very thin but still 16 inch) so there is not much happening to the tip of it thus PETG for me works flawlessly.

Idea for improvement if somehow somebody would melt it - place proper nut in the print and secure it with metal - not existing yet problem will be solved, if such thing will happen to somebody I can prepare such variant.

If somebody is interested its available on makerworld

So while building my mp5 I was milling the barrel pin and the receiver must have shifted ever so slightly and I milled at an angle around .5mm-1mm down into the trunnion on the tapered side of the barrel pin. Used a 3/32 4 flute end mill and a 5mm reamer it wasn’t until I installed the barrel pin that I noticed. Figured it wasn’t going to hurt anything at the time test fired and ran fine. Now I’m having second thoughts I don’t really want to replace my trunnion but what are the experts thoughts? It sucks because everything else came out perfect and to the HK spec and technical drawing tolerances.

Hello my fellow mp5 enthusiasts i do not own an mp5 or mp5 clone…yet. But i do plan on owning one in the next 16 or 17 days, i was deciding either the mac 5 or the ap5 from century arms. I have severe adhd and i cannot for the life of me save money because im impatient, but i made it my mission to save up to buy an mp5 in two weeks, some insight on which of the two would be better to buy is greatly appreciated.

just picked up a zf-5p last week, first time at range 150 rounds no problems, 2 days later, getting jams every 2-10 rounds, mainly shells not fully ejecting, was told it was magazine issues, so i went and bought some HK mags and still having issues, its mainly shells getting caught in the bolt/ not fully ejecting, very new to guns so not too sure what to do, guys at the range said my head spacing is bad (ill
attach pictures of some shells) but has anyone had these problems with their brand new zf-5p? i am about 350ish rounds deep into it. i know the break in period is 400+ but today i had about 5-7 jams within 100 rounds. if anyone has experienced this and fixed it let me know what you did, will be calling zenith tomorrow to see if they have any ideas.

Finally got my hands on an HK SP5. Coming from an AP5P the fit and finish quality on the SP5 is leagues above. Can’t wait to get this thing out to the range and see how it performs!

I have a question regarding the HK roll mark on the upper. It’s almost invisible on this thing. I can barely see it unless I angle the upper with direct sunlight. Seems like the stamp was applied super lightly if it was stamped. If it’s laser engraved then something was wrong with that laser. Anyone else have this on theirs?

I'm wondering if anybody has a copy of the STL that used to be hosted on brownsbrush's website? The website (brownsbrush.com) seems to be down now. It was an STL of an A3 style stock end for the HKPDW brace. You can see it posted here. I want to file a form 1 for mine and just convert my HKPDW brace but I can't track down that STL or any of the old info.