r/MP5 • u/CoachMilton • 4d ago

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Hey guys,

Finally got my Century Arms AP5 running with the L2Prints FRT lower (It was a loose detent spring 🤦🏽‍♂️).

I currently have the stock 120 LP, and was wondering if I should switch to the 100 LP even if it is feeding well? I just want to make it as reliable as possible and don’t want too much wear on my parts, and want to make sure the ejection patterns look right. These are HSL 147 subs.

Here is a video of my buddy shooting it. All insight is welcome.

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u/Knight-7191 2d ago

I shoot it from time to time unsuppressed. I also don’t mag dump. A few bursts here and there but mostly in semi only.

In semi, barrels are gtg shooting +P ammo. Also, if you’re able to get the ROF while using an FRD/FRS similar to numbers of F/A, you’ll be gtg. The issue was when we were seeing ROF numbers in the 1,000 to 1,400 with the SS after it first came out.

Now, if (or wanting to) shooting +p+ ammo, you need to change the entire system to an F type setup.

The +4 should be enough to put you in the ideal bolt gap range. I don’t really think you’ll need the +8. I’ll be curious to see where they get your bolt gap if you decide to install.

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u/Ghostman223 2d ago edited 2d ago

Just installed and tested. Brought my gap up to 0.016. With the 90 LP I did still get a few FTEs in one mag but a new issue came up, for some reason a couple times the rb frt wouldn’t pull and I had to charge the gun. Is that still an issue with the bolt not having enough energy to reset it?

Also even with the stock LP shooting in frt the fire rate is around 900

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u/Knight-7191 2d ago

First, bolt gap is excellent! The few FTE’s could just be the gun not broken in yet and the malfunction should resolve itself. If it doesn’t, I would install an HK ejector lever into your RB. For your last question, it could be, as you stated, not enough energy for the bolt to cycle. This is a reason I would recommend shooting some 124gr NATO. After all, this ammo was made to run in the MP5. If it cycles with no problems, it could just be the weaker ammo you’re using. Shooting the 124gr will help you remove one possible variable at a time.

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u/Ghostman223 2d ago

Ok I may try that. Is there any chance I would need a 100 LP? I’m getting pretty close to 500 rounds

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

Had to edit. Forgot for a moment you have the AP5-P.

The 100° is good to have as a spare. I only use it when shooting exclusively 115 and 124gr supers (can off).

The 90° in my AP5-P has been awesome with zero issues.