[Ninja_En_Short]

OK first thing : you are not suppose to get the dot on the impact, don't feel bad that's the first thing I teach my trainees and they all do the mistake.
The dot is suppose to be in parallel line with the barrel which means, with the dot more or less 2.5 inches above barrel the impact is supposed to be 2.5 under the point you aim. It's your job to work with the distance. The red dot is there for faster and easier target acquisition, not to do your job

Second : the G&P is just a repack of a chinese cheap copy (I used to have both). You will not get a very good setting and the recoil will mess with it quickly.
If you can sell it and buy a Vortex red dot or other cheap RS sight for what you want (http://www.opticsplanet.net/vortex-r...sfrd-hunt.html). It's still cheap and you'll have better results.