>>64095841
Sig quality control and a barrel that's absolutely clapped out after only 2000rds total, leading to groups so loose that they would make a last ditch WW2 weapon blush.
If you want a full power infantry rifle, the Spear is unironically worse at being one than an old FAL, G3, or M14, so the Spear isn't just doctrinally obsolete, it'd also be really fucking terrible at the older kind of doctrine of such rifles.

>>63925511
They kind of have to, because according to soldiers testing it in the field, it both sucks really hard in execution (Sig lmao), and soldiers trying it out don't see any purpose in trading more recoil and +50% reduction in ammo for more range and more penetration.
The supposed sci-fi optic isn't really doing it any favors either, because soldiers are complaining that the rifles are coming with crooked rails/barrels/both (a problem known to the MCX as well), and that they usually shoot about 6MOA anyway, and then the machinegun doesn't feel like extracting fired cases very often, so it's not doing so hot either. Burst cases are also common with both guns.

The only reason this program didn't just fall apart years ago is that Sig, in spite of being the absolute worst entrant (by a wide margin) to the already dubiously conceptualized NGSW program, bribed themselves towards victory.
The only hypothetical chance the NGSW concept has is for the army to kick Sig Saar out, scrap their fleet of weapons, and then make sure to deliberately exclude them in a new trial for a Next Generation Designated Marksman's Rifle.