Sandeen says that the Army only listens with Winchesters. BUT the Winchester was not an official weapon of the Army. To have achieved accuracy Sandeen would have had to have said the Army only listens with Springfields (the official weapon of the Army and the weapon that troops would have carried, rifle or carbine). Further, at the end, General Frye and the soldier with him pull Winchesters when Cinto Morado rides into Sweetwater. Again, the cavalrymen would NOT have had Winchesters. Instead, they would have had Springfield carbines. And General Fry (a commanding officer) would have had a Single Action Army Colt (AKA a Peacemaker). Officers would NOT have carried Springfield carbines.
At the end, General Frye allows Cinto Morado to leave Sweetwater unmolested. If Cinto Morado had fled the reservation, he would have been declared a renegade, and Frye would have been charged with returning him to the reservation, by force, if necessary. There would have been NO option here for Frye. To have done so otherwise would have amounted to a dereliction of duties, and charges would have been brought against Frye for disobeying his orders.