Looking up pistol blue prints will need some type of clearance. You can get the basics from a few sites. Some are on sites that have adult content. You will get the basic lay out of pistols but will need to register to get detailed blueprints. Follow this link to look at the blueprint and to register if you like http://www.the-blueprints.com/blueprints/weapons/pistols/17915/view/desert_eagle/.
