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Q&A for Heckler & Koch Complete MR556 Upper Receiver Kit — 9 Questions & 1 Answers

Name Heckler & Koch Complete MR556 Upper Receiver Kit (5)
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Q
RMIII, member, from FL, United States, asked on September 10, 2022

Would this H&K model upper be piston; if so is there adjustable gas settings?

Expert Answer
A
Answered by Ethan, Gear Expert, from IL, United States, on September 21, 2022

The Heckler & Koch Complete MR556 Upper Receiver Kit uses a gas piston setup, however, it is not adjustable.

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Q
Ken, member, from CA, United States, asked on September 05, 2024

This upper require special trigger groups?

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Q
Mike, member, from CA, United States, asked on August 21, 2024

What do I need to do to adapt this upper to a milspec AR lower?

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Q
Charlie, guest, from CA, United States, asked on March 25, 2024

Will I be able to put the geissele super modular rail on this?

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Q
P80mustang, member, from CA, United States, asked on March 23, 2024

Does this upper come with the gas block and piston op-rod installed?

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Q
walter3ca, member, from CA, United States, asked on March 17, 2024

Is this the MR556A1? Will it drop into my Olympic Arms lower?

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Q
Ken, member, from CA, United States, asked on January 17, 2024

MR556 inside the upper is mark .223 , can I shoot 5.56 with it?

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Q
Runningjalapeno, guest, from TX, United States, asked on December 26, 2023

Can this upper be used on any lower mil spec lower?

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Q
The Gun Slinger, member, from CA, United States, asked on December 06, 2023

Would this upper work on a dedicated 5.56 milspec lower receiver?

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