That's pretty much what we did in BCT, except they were inert grenades. There was a 55 gallon drum at each end to lob them into. That became possible due to the ballistic trajectory of the throwing technique taught. When we had down time between scheduled training we squad leaders were to take our men out to the company grenade field to practice.
If we saw one of the trainees was weak in any skill, it was our job to bring them up to speed. This was in 1965, so always on our minds was many of us would be facing real war in a few months.