Rob Allen Tuna Roller Gun is unlike conventional spearguns in which the rubber bands take up only 30-40 per cent of the barrel length, the roller speargun allows you to utilize the full length of the barrel, as the spear shaft is accompanied all the way to the end of the barrel. Essentially, the roller speargun gets its extra power from the longer band pull, instead of more bands. Likewise, the pre-tensioned rubbers underneath allow for more power and strength right up to the end of stroke. Resulting in more speed and momentum. This increase in power of the Rob Allen Tuna Roller Gun allows for more penetration on the target and more accuracy and range of your shot. Another advantage to roller guns is the way the have less recall due the roller counter acting the rubber releasing both ways.