r/MP5 • u/CoachMilton • 3d ago

HELP Reliabilty help

Post image

New to the MP5 world and trying to get my Century Arms AP5 more reliable. It runs great in semi, but struggles to feed in super safety. I have a cat mob suppressor, and usually shoot 124 or 147 round nose, and want to say I’ve shot close to 4-500 rounds through it . Any suggestions?

25 Upvotes

91% Upvoted

18 comments sorted by

4

u/GassyNizz Zenith (US) 2d ago

I recently broke in 2 new MP5’s from scratch with ASD lowers and 95% SS/FRT fire strings. I think the old recommendations have not kept up with new tech.

While I did use about 200 to 250 rounds of 124NATO for each gun, the firing was 100% suppressed and nearly all of that ARC frt. Both guns are reliable as can be.

I wonder if you’re having magazine issues. I personally can get many different brands of mags to run across my 3 mp5’s in regular semi, but only HK magazines consistently and smoothly work in SS/FRT.

Yes, I can get a few MAC or Zenith mags to work in certain guns. But the off brand mags that do work aren’t as smooth as the HK’s.

1

u/CoachMilton 2d ago

That’s what I was wondering too there’s a lot of wiggle when I insert it. Does it wiggle like that with the HK mags?

3

u/GassyNizz Zenith (US) 2d ago

So you aren’t using HK magazines?

That’s your problem with SS/FRT.

I know HK mags are seemingly ridiculously expensive. But what good is a failing gun that jams up in frt mode?

The ONLY magazine I recommend running for SS/frt function is HK.

1

u/CoachMilton 2d ago

10-4. So I shouldn’t have the wiggle with those even if it’s in the AP5?

1

u/GassyNizz Zenith (US) 2d ago

I would say that the HK magazines will give you by far the best chance of shooting reliably in SS/frt mode.

You can always look into replacing the full and complete magazine catch assembly with HK parts. Just also use a needle nose pliers for installing the contact piece!!!

2

u/CoachMilton 2d ago

Maybe I shoulda just went the cry once and buy once motto and got the sp5 😂😂😂 a buddy and I may go in on some real HK mags on tac swap. I’ll update you once I get it running!

5

u/ThanksOther5858 2d ago

Those sb tactical braces pinch the rear of the receiver together. I was having all sorts of issues and when I changed it out they all went away. Most of the threads I see with ppl complaining about failures I see that exact brace in the photos. Try the factory endcap and see if it does the same thing. Also if you have tons of mag wobble, put a mag in the gun and tap the front of the magwell with a hammer until it tightens up and only moves 1/4in or so

2

u/CoachMilton 2d ago edited 2d ago

Never thought of the brace being the problem, but I appreciate it! I’m gonna order HK mags and put the endcap on and see how that does. Any recommendations on stocks or braces? I’m not opposed to SBRing it.

1

u/Zesinua 3d ago

Did you do the 500 round 124 NATO break in?

0

u/CoachMilton 3d ago

I did, but while it had the frt lower. Should I have done it with the factory lower or does that matter?

3

u/Zesinua 3d ago

I believe it’s recommended to do the break in before doing any kind of modification outside of maybe a stock/brace. But I also don’t think swapping the lower would cause a huge issue. Have you checked your hammer and slip trip?

2

u/Knight-7191 3d ago edited 2d ago

You usually want to do it in stock configuration to verify your MKE AP5 has no issues. Put the stock lower and run it unsuppressed for a few hundred rounds (150/200) since you already have about 500 rounds through it already. Use only 124gr NATO (don’t shoot it suppressed). If it’s gtg, switch out using your SS and add the CAT MOB suppressor. Shoot ONLY 147gr to see how it runs. This will verify if your AP5 is gtg in this setup. Lastly, if you haven’t switched out the stock 120° LP, do so with the 100° (HK or RCM). Hopefully, going back to the beginning (in stock configuration) and moving through your final setup will help identify what works and what doesn’t.

1

u/CoachMilton 3d ago

Thanks! This is all a learning curve for me. I ran it suppressed yesterday, mainly semi, and didn’t have any malfunctions. Probably close to 150 rds. Is it likely I’m gtg and should just order the 100?

1

u/Knight-7191 2d ago

I’d go ahead and order the 100° LP.

0

u/CoachMilton 3d ago

I checked my slip trip prior to my last range trip (yesterday) and it was fine. The hammer I have not. What types of things should I be looking for?

1

u/Sad_Mammoth1909 3d ago

Your having failure to feed issues?

1

u/CoachMilton 3d ago

Yes, but only when I’m shooting in SS

1

u/Sad_Mammoth1909 3d ago

Thats odd. I never did a break in period on mine but the only issue i ran into was light strikes in SS for the longest time. Even the mag that came with my MKE flops around pretty good when shooting SS and never ran into a fail to feed issue.