Richie Morgan offers this large scale chiasm
A Samuel succeeds elderly Eli and rules over all Israel (1 Sam. 1-7)
B Saul’s Failure (1 Sam. 8-15)
C David’s initial rise to popularity in Saul’s kingdom (1 Sam. 16-20)
D David flees; Saul has priests killed (1 Sam. 21-22)
E David saves city of Keilah (1 Sam. 23:1-18)
F Ziphites betray David and he spares Saul’s life (1 Sam. 23:19-24:22)
X David and Abigail (1 Sam. 25)
F` Ziphites betray David and he spares Saul’s life (1 Sam. 26)
E` David protects towns in Judah (1 Sam. 27)
D` Saul and sons killed (1 Sam. 28-31)
C` David’s initial rise to power over all Israel (2 Sam. 1-8)
B` David’s Failure (2 Sam. 9-20)
A` Solomon succeeds elderly David; David’s final years (2 Sam. 21-1 Kings 2)