Well it's hard to tell, some people use different styles of play, however smart parts is pricey, so you may have to spend $500-$900+!
There are a few places where someone could purchase a Smart Parts Ion paintball gun. A store like Sears, and websites such as trademygun, and ultimatepaintball, all sell Smart Parts Ion paintball guns.
3skull is a company that makes aftermarket parts for tippmann, spyder and smart parts guns.
a new feed neck or a drop forward
about the same as anyone else.
The paintball gun does not use any parts that have not been make in other industries before.
No one has a patent on the "paintball gun" several companies have patents on their valves and other parts, but no one company can paten "paintball guns"
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Canadian Tire has the best deal on paintball gun packages. One can also get best deal from paintball online store. Amazon has Tippmann 98 package for $154.
Smart Parts Ion, Dangerous Powers G3, proto Slg, and Invert Mini, are the most common speed ball guns.
a cheap good one is the smart parts vibe and for a little more the azodin blitz. the vibe shoots 11bps and costs $160 with ship. the blitz shoots 20bps for $170 with ship. i suggest the blitz though.
You disassemble it, and apply a non aerosol airtool or paintball lube to the o- rings and major mechanical parts.
eBay is the best way to sell