I have seen these plastic/rubber "bullets" around in cabelas and bass pro shops. They are better than dry firing w/ a previously fired case in the chamber.
Practice firing your gun is the only way to get better at not flinching on your end, on the guns end I would not be suprised if the stock settings on the stock trigger *if its even adjustable* would be totally un usable. Its a Anti gun Demy trick they forced down the gun manufacturers throats on us. It goes like this, "if we can't take their guns then we will make them unusable" and so they allowed frivolous law suits to run the weak gun manufacturers out of business *scaring us all and ruining many pairs of pants* and forced the remaining gun manufacturers to set the triggers at some ridiculously high poundage so you can not shoot accurately.
Have it checked, and you may want to have it adjusted. I have all my guns fitted with an after market trigger assembly because no factory trigger can hold a candle to my Timney triggers. They are smooth as silk, crisp as can be and light as can be. Just a joy to go shoot.
I warn you though, Timney's are expencive and once you get one you will want one on all of you guns. Timney's=wallet rape Luls