DB sessions randomly logging users out

[eluser]CI_Newb[/eluser]
So in my tests, sessions worked fine. But once I went to production (same server, just more users) every now and then, my users will say it randomly logs them out. Not often, just randomly.

Here's how my config looks now trying to solve this problem.

Code:

$config['sess_cookie_name']        = 'ci_session';
$config['sess_expiration']        = 0;
$config['sess_encrypt_cookie']    = FALSE;
$config['sess_use_database']    = TRUE;
$config['sess_table_name']        = 'user_sessions';
$config['sess_match_ip']        = FALSE;
$config['sess_match_useragent']    = TRUE;
$config['sess_time_to_update']     = 25200;

This is all within a secure network so i'm not worried about attacks or stuff, I just want it not to time out for the duration of the users shift.

Any ideas?