Editor recommended because this is the officially named Prestige Attachment for MXR-17. It is not labeled BEST. Tradeoffs are quoted from official launch copy.

MXR-17
MagazineMFS Semi-Auto Fast MagReach maximum Weapon Level and Prestige the weapon.
Converts the MXR-17 into a powerful semi-auto weapon with a unique blend of firepower and handling. Faster to aim and reload with reworked recoil and more damage fall off.
Attachments 1
- MagazineMFS Semi-Auto Fast MagReach maximum Weapon Level and Prestige the weapon.
Converts the MXR-17 into a powerful semi-auto weapon with a unique blend of firepower and handling. Faster to aim and reload with reworked recoil and more damage fall off.
Alternatives
- Base weapon / no prestige attachmentKeep the base gunsmith path if you do not want the official prestige tradeoff quoted above.
Evidence basis: Source
For streamers: add this as an OBS Browser Source — stream widget
Recommended · bo7-mxr-17-prestige-launch