资料参考：
https://thedefensepost.com/2026/02/23/us-marines-m7-weapon/
https://www.twz.com/10147/the-army-is-once-again-looking-to-replace-the-5-56mm-cartridge
https://www.twz.com/land/army-captain-slams-new-xm7-rifle-as-unfit-sig-sauer-says-otherwise
https://www.armytimes.com/news/your-army/2017/10/08/the-armys-next-generation-squad-weapon-could-change-the-way-you-fight/
https://www.military.com/kitup/2010/03/us-army-outgunned-by-afghan-insurgents.html
https://taskandpurpose.com/news/m7-pentagon-testing-office-list/
https://taskandpurpose.com/news/m7-pentagon-testing-office-list/
https://x.com/JakOSpades/status/2067172486014243115
https://armourersbench.com/tag/sig-m7/
https://modernfirearms.net/en/assault-rifles/u-s-a-assault-rifles/ngsw-r-sig-mcx-spear-2/
https://militarnyi.com/en/news/ngsw-weapons-has-received-negative-assessments/
中文参考：
https://zhuanlan.zhihu.com/p/511243183
