I pretty much agree with the above: Oehler 35 or 35P, especially if you shoot at a private range where there's no problem setting it up.
If you mostly or totally shoot at a public range where setting a chronograph in front of the benches is a problem (and maybe even against the rules) I would go with a Magnetospeed. Due to being mounted on the muzzle-end of the barre, they do tend to the change point-of-impact and accuracy, often a LOT on sporter-weight barrels, but they can also be set up off the barrel in various ways.
