GO conducts accuracy test firing of upgraded NORA B-52 M21 system 14 April 2021 (Last Updated April 14th, 2021 11:00) Global Ordnance (GO) has performed the accuracy test firing of an upgraded NORA B-52 M21 155m mobile howitzer system. Share Article NORA B-52 M21 Performing Accuracy Test Firing in Serbia – April 2021. Credit: Global Ordnance LLC. Global Ordnance (GO) has performed the accuracy test firing of an upgraded NORA B-52 M21 155m mobile howitzer system. The test was conducted along with Serbian manufacturer Yugoimport SDPR before shipping the NORA B-52 system to the US to participate in the army shoot-off and evaluation programme. During the evaluation, NORA will be put through its paces in various tasks to help the US army to decide, which system(s) meets its requirements.