My roommate just rebuilt an old scwhinn collegiate, and replaced the handlebar stem.
for some reason though, the stem won't go all the way down, so it's looking a bit awkward. Any ideas as to why it won't go down all the way?

Is it a very tiny frame? Sometimes you might have problems with a tall stem and a small frame with a short head tube.

If you post a couple pictures it would probably be easier to diagnose.

He's out riding at the moment, but I'll post pictures asap. Thanks!

Check the diameter of your new stem and the original. Schwinn used to use some parts that weren't common sizes. I'm thinking that stems may be one of those.

Yeah, we went to our lbs, and they did have to order the stem because they don't actually carry them. So it should be the right size, but maybe maybe too long? or there could even be something inside keeping it from going down i guess. i'm going to try to get some pictures up soon.