Inspect the momentum ratios. Even if momentum is conserved for a given collision, the measured values may not be exactly the same before and after due to measurement uncertainty. The ratio should be close to one, however. Is momentum conserved in your collisions?

In my honest opinion yes momentum is conserved

Explanation:

Due to inaccuracy in measurement or bad calibration of measuring instrument say (impact testing machine) or parallax error from the measuring instrument, it is quite possible for us to get results that seem as though momentum is not conserved.