Ballistics is a function of several factors. Barrel length, bullet weight, etc. Here is a site you can download a free ballistics program with clickable variables. Want to see the path of the bullet from your 94 30-30 at 300 yards? Just click on the ammunition you're interested in and click "fire". I've used it for some time and it's a great little program.
http://www.tripolistriggers.com/nss-folder/ballistics/
Update: That link is no longer active, and I wasn't able to find another similar. Your best option is try the Winchester web page (http://winchester.com/products/catalog/rifle.aspx ) and select the appropriate options from the right hand side of the page.