What's the movie where a police officer ends up being the bad guy and another cop tells him that he should us a g lock because they don't jam. The final scene takes place on a shipping frieghtor and they fall into a huge thing of grain or something like that and the good cop shoots the bad cop with his glock which didn't jam? I feel like its an older movie but I'm not sure.

I'm going to say US Marshals
http://www.imdb.com/title/tt0120873/

At the end of that film Tommy Lee Jones shoots Robert Downy Jr. for being the bad guy and saving Wesley Snipes in the process. And that takes place on a tanker in a bunch o' grain. Also earlier on in the movie TLJ is talking to RD Jr. about using a glock cause they don't get messed up when wet.