Spirit of Pickett,
There are two films, the aggregate of which, may comprise the picture you saw ages ago.
1) Major Dundee (1965) 136 mins., with Charlton Heston as the Federal commander of a southwest post housing Confederate POWs commanded by Richard Harris. Heston & Harris combine forces to chase raiding Apaches into Mexico & kill them. The film ends with a border fight against French forces in order to recross the Rio Grande.
2) Cavalry Charge (1951) 88 mins., aka The Last Outpost, with Ronald Reagan commanding
CSA forces raiding gold shipments along the Santa Fe Trail & Bruce Bennett commanding USA forces sent to stop the raids. Bennett doesn't know that the opposing commander is his brother Reagan. Mix in the brother's competition for love interest Rhonda Fleming. This wasn't called the Brothers' War for nothing. The film ends with the
CSA forces charging the Apaches about to wipe out the USA forces.
I recommend two titles regarding the War & film. Blue & The Gray on the Silver Screen: More Than 80 Years of Civil War Movies, 1996 by Roy Kinnard. The Reel Civil War: Myth Making In American Film, 2001 by Bruce Chadwick.
Hope this is of service.
Regards,
Edwin Carl Erwin
proud descendent of Tobias Levin Hays: 16th Texas Infantry, Co. I,
CSA & 22nd Brigade, Mesquite Company,Texas Rangers.