H&K USA is releasing the gas-piston, MR556A1 upper assembly to the market. Ever since a limited number of HK416 upper receivers showed up for sale on internet websites several years ago, fans have hoped that they would make the MR556A1 upper available for general sale and its finally happened.
The upper receiver kit will include a barreled flat top upper, Free Floating Rail System handguard, bolt carrier assembly, buffer, and buffer spring. The bolt carrier assembly, buffer, and buffer spring are all different than standard US Mil Spec items.
Fortunately, the MR556A1 features the same take down pin geometry as US Mil Spec Carbines so you will be able to plug it right in. Some variants of the civilian model do not share this feature.
Since it’s an upper, you can purchase the assembly as a part to attach to your existing gun so you won’t need ATF approval. However, make sure you are sitting down when you read this next part. The MSRP is reportedly $2195.