Complex sentence: Once ready, they were sent to the front armed with a dagger and hand grenades, most didn't carry rifles or carbines because they would be cumbersome to fire in the confined spaces of a trench.
Split into simpler sentences: Once ready, they were sent to the front armed with a dagger and hand grenades. Most didn't carry rifles or carbines because they would be cumbersome to fire in the confined spaces of a trench.