Nope, it's enough. 800 random people out of the population is a pretty reasonable sample size. I am going to guess you don't understand the link you posted, which pretty much shows the opposite of what you're saying. SAMPLE SIZE DOES NOT NEED TO BE PROPORTIONAL TO POPULATION SIZE.How do you know 800 is enough to form a statistically relevant percent? I have no idea, but after reading this, I suspect that it may not be enough.
These guys are a bit liberal, but it's a good read on why huge sample sizes are not really as helpful as some people think:
http://www.publicagenda.org/pages/best-estimates-guide-sample-size-and-margin-error
Loaded questions, skewed samples, etc. are different problems. The number of people polled is not. We ask gun controllers to not be ignorant, let's not show that same ignorance of basic statistics on our side, please.