Rider and Lancer vs. Caster and Berserker

Herc mauls them to death.

Archer was killed in canon against Herc after taking 6 lives away from him. Caster needed to summon Assassin, and wanted to take Saber to her side because she knew that she had no chance against Herc.

We do have info on Rider's abilities though.

 

But he didn't have support from his master mana wise.... more importantly he didn't use Excaliblar or caliburn, plus if with the swords he copied throughout the time, archer managed to kill him 6 times, then with more swords he could sure kill him 12 times

plus can't Excaliblast just blow him out before he recovers, like one hit shot, I mean it should physically be impossible for him to regenerate from nothing..

 

Archer is one of the weakest Servants in the Grail War due to not even being a legitimate Heroic Spirit. He has absolutely no chance of beating anyone outside of under-handed tricks. He lost to Herc even after pushing himself to the limits. And yes, he recieved support from his Master mana wise regardless of the fact that she wasn't there. In fact, you could argue Archer was in a more advantageous situation due to not having to protect his own Master.

Also Archer doesn't have too many high levels swords as all of his ''copies'' are reduced by a Rank or two. His Kanshou and Byakuya are only C- rank while the original ones were A rank, for an example. And he can't project Excalibur nor Caliburn without going through the same events as Fate!Shirou who could only reproduce Caliburn. Excalibur would kill them both due to their Magic Circuits being fried when trying to project such a high level NP.

Most of his fights are won through under-handed trickery or advantegous situations (ex. using Kanshou and Byakuya's magnetism by combining them with the rotation technique to trick Medea into lowering her guard, allowing him to take her by surprise). He's not too good at straight forward fights as seen when he gets utterly demolished by Cu Chulainn when the latter is allowed to fight him seriously unlike their first time.

Six times is the limit of how many times Archer can kill Herc.

Illya states Excalibur's full power could take off 5 lives at the very most. A weakened Excalibur probably can't take off even two lives according to her. And if by a miracle Archer pulled off an Excalibur projection - which is impossible for him basically-, it's dubious that he could take off even one life with such a knock off version.