The weight of one bullet or ball.
Both light and heavy shells have their advantages and disadvantages. So, a small weight allows you to achieve a high initial speed, but it is quickly lost due to air resistance. Conversely, a heavy bullet "starts" slower, but retains speed longer. However, in fact, such nuances are necessary mainly for professionals and enthusiastic enthusiasts — hunters, athletes, fans of high-precision shooting, etc. If bullets are bought for entertainment, initial training and other tasks that do not require special accuracy, you can not pay much attention.
As for specific weight values, they are directly related to the caliber. So, bullets of the most popular 4.5 mm caliber in our area with a weight
of up to 0.3 g and
0.3 – 04 g are considered very light,
0.4 – 0.5 g and
0.5 – 0.6 g are light,
0 ,6 – 0.7 g and
0.7 – 0.8 g — medium,
0.8 – 0.9 g and
0.9 – 1 g — heavy, and the most massive may
exceed 1 g in weight. In turn, balls of the same caliber rarely exceed 0.5 g in weight. For larger calibers, respectively, the numbers are larger: the weight of a 5.5 mm bullet can reach 2.5 g, 6.35 mm — 5 g, 9 mm — 10 g .