The Slidefire (and other similar bump-fire stocks) is basically a toy when used form the shoulder. A genuinely fun toy, to be sure, but still a toy. However, we have reason to suspect that when used on a rifle with a bipod and large ammunition capacity it might actually do a good job of duplicating a true light machine gun without the cost and NFA paperwork.
As a first step in testing that hypothesis, Ian took a Russian semiauto RPK with a Slidefire stock to this month's 2-Gun Action Challenge Match. The goal was to see if it showed enough promise to be worth further practice and experimentation...
...and the answer is that it definitely is. Ian's match score was terrible, and the gun had several problems (mostly due to unpracticed handling of the Slidefire), but the potential was apparent.