Old mil-surp ammo is often unreliable, slight hang-fire noted on third shot in the Youtube clip.
Berdan primers are a nuisance when reloading too.
...but the marvelous 205gr spitzer FMJs that retail here in Oz from time to time are perfect! I just recently loaded a few WR .318 rounds with that bullet, being .330 diameter, but haven't banged them off yet.