In a surprising turn of events, Sauer has, yet again, decided to shake up the norm in their rifles' mounting surface design. Just when the dust had started to settle after the transition from the older ISI versions to the SUM mounting surface, which became a standard for all Sauer 404 rifles, a new development emerged. After only four years since the establishment of the SUM surface, a new adaptation of the SUM mounting surface has been introduced, leaving some users puzzled.
The resulting changes have given birth to two versions of the SUM mounting standard. Users might be scratching their heads, wondering why such an alteration has been made in the first place. Our mission is to share with you our latest findings on this topic to make your life just a little bit easier.

What Does This SUM Change Mean?
From the information we have managed to gather, this design modification quietly took place in 2022. There were no grand announcements made to the end users, nor were there clear indications in the latest catalogues, leaving users somewhat in the dark.
So, why all the fuss? Essentially, the key concern lies in the significant impact this has on interchangeability between the newer and older models.
The new generation SUM mounts, manufactured after 2022 can be fitted onto both newer and older models of Sauer 404 rifles. However, the previous SUM mounts produced up until 2022 are not compatible with the newer Sauer 404 rifles.

This lack of interchangeability can be traced back to design changes in the recoil notches of the newer mounting surface on the rifles and the corresponding recoil stoppers on the mount. The newer scope mount version introduces two recoil stoppers, sloped at an angle, contrasting with the older versions' single, straight stopper.

INNOMOUNT has quickly adjusted to changes and now provides an updated version of the scope mount. However, if users plan to transfer optics from their older Sauer 404 model to a new one, a new mount is required. All mounts promoted by INNOMOUNT as compatible with the Sauer 404 SUM will now feature this updated version of the mounting surface, and the older version will be discontinued. We also anticipate that other manufacturers, such as MAK or Henneberger, will likely adjust in a similar fashion.

Final Thoughts
This should dispel some of the mystery surrounding the topic. However, while we believe, that while technical advancements and the reliability of SUM mounting solutions are greatly appreciated, changes of this magnitude should be clearly communicated to end users in advance. Such an approach would not only encourage trust but also help users in making informed decisions about their purchases and their user experience.
While we appreciate Sauer's innovation and drive for improvement, a little more transparency would go a long way in ensuring a better user experience. After all, a well-informed user is a happy user.

