Aside from the backyard blasphemy, your best bet is getting something else. Most people automatically want to be a sniper because in video games the sniper has the most accurate shot, the longest, etc. This is airsoft, keep that in mind. FPS limit difference of an AEG and a bolt-action is about 50, 100 in rare cases. Your range won't be that much more superior, either. Accuracy will be a little better just due to the length of the barrel, but keep in mind that an AEG just has to spray at you, and while spraying adjust his aim to hit you. You have to land the shot within the first 2 or 3 otherwise you're more or less down.
A lot of people start with an AEG to get used to the mechanics of the game. Mainly, the physics of it. Most people that are snipers are dedicated to it, and have spent up to, if not more, than $1,000 upgrading the weapon to bring it to peak performance. Between me and the people I play with, there's only one person with a sniper, and it is an L96. Yes, he does have a slight advantage over us, but he spent a lot of time and money in parts making sure he'd be capable of gaining that advantage. If you're just plinking in your backyard with someone, I'd probably suggest a clearsoft and spraypaint it from Wal-Mart or something. Anything else is probably too pricey just for backyard plinking. Not to mention wal-mart rifles have a drastically reduced FPS (like.. 200FPS), and is much safer than firing something that is nearly 350FPS at that range.
Primary: Custom WE M16A3
Secondary: KWA MP9
Side: Custom WE M1911A1