Hk MR556 kingpin and maglock?

[tiguu]

Hi guys,

I recently got HK MR556 A4 lower.

I usually run ar maglock, kingpin, and klvrco king pal.

I read that these aren’t compatible with HK MR 556 A4. Is that true?

If so, what are my options without using comp mags?

Please let me know!

 

[SlayingMantis]

Featureless. Pinned stock, compensator instead of flash hider, and fin grip. Superior to mag lock anyways

 

[bonesurf]

interesting. my mr556 (not a4) came with a kingpin/maglock