I have a Glock 31 and have been reading through the forum to learn what I should do, where to go, etc. to sight my Glock 31. I've only shots a few hundred rounds, and it always seems to go down and to the left. This has happened with multiple people shooting it, so I know it's not an unsteady hand on my part. I've always used UMC 357 SIG (yellow box, 50 rounds in a box I think). Any ideas on what ammo would be best, where I can take it to get some professional help to sight it (and test fire, of course)? I live in Portland, OR.