This model is largely the same as the 1851, only slightly different, including the grip length, the length of the cylinder and the shape of the barrel, and the assembly is basically the same.

Screws ：

• M3 x 6mm*2
• M3 x 8mm *3
• M3 x 10mm *3
• M3 x 12mm *2

Cut some filaments：

• 1.75mm*6mm
• 1.75mm*8mm
• 1.75mm*9mm

Spring：

• 3mm*0.4mm*12mm

Because I didn't find a suitable exploding diagram, I could only take the 1851 as a reference, and the position of the screws was basically the same.