So I've been hearing rumors on the DL that since the first XM7s (and XM157 optics) started reaching the 101st Airborne this year, they're apparently not well-liked by the paratroopers that have been issued them. The biggest complaint - surprise surprise - is the weight of the rifle/optic setup. I'm also hearing that HQDA is already discussing whether to scale back the current procurement plan. There have already been at least a few public statements where the Army has suggested that the M4A1s will remain in the inventory of the units getting XM7s, which suggests that they've already not confident in their idea and intend to hold the M4A1s in reserve until the T&E period results come back.
For those who missed it - Jeff Gurwitch (former Army SF) already put out his take more than a year ago on why the XM7 was a bad idea:
https://www.youtube.com/watch?v=YdAYSEm5zJA
His key points:
(1.) XM7 is too heavy, and larger caliber = too few rounds per individual infantryman. (In a firefight: The name of the game is to throw a lot of rounds down range to break contact and keep enemies' heads down.)
(2.) The entire idea of the XM7 (then called XM5) was to achieve overmatch over enemies armed with long-range weapons (e.g., Dragunov and PKM) at the individual rifleman level, which is a fallacy from the get-go. He argues that an infantry rifle like the M4 tends to get used more as a personal defense weapon - the actual effects on target come from heavier weapons and/or air support.
(3.) Russian and Chinese body armor was also a factor, but the Ukraine War is demonstrating that in combat against near-peer adversaries in urban environments, a more traditional carbine in a caliber like 5.56 or 5.45 - and equipped with a good old-fashioned red dot optic - works fine for the type of combat that we and/or our allies are likely to experience. An XM7 with the XM157 would be a horrible choice for this type of conflict because urban/village combat is where most firefights take place, while longer-range engagements involve artillery and drones, not infantry weapons.
(4.) A typical Army SF ODA never felt out-matched in a firefight in Afghanistan, because they had a variety of longer-range weapons in 7.62x51mm such as the SCAR-17S, MK 48, and M240 to use in response to fire from PK/PKM or Dragunov-wielding enemies. He thinks it would have been more efficient for the Army to procure some of these weapons and re-structure the firepower of a typical infantry platoon to match what an ODA carries so that there are more longer-range weapons available.