I got a scope mount for my Savage .308, and after about 20 rounds the scope rattles around in the rings.  Even the base gets a little loose.  I'm using the kind of scope mount with two pieces of railing that you screw into the gun, and the ring pieces slide into grooves in the side of the rail.  The screws are tightened with an allen wrench.  Do I need a better mount, or do I have to tighten it more or something?

If both the rings and the mounts are coming loose then I would say you need to tighten them more. The screws securing the mounts can be tightened with quite a bit of force but more care is needed for the rings especially if you don't plan on lapping the rings.

I would also suggest using Blue Loctite.

need more info.
who made the rings and base?
i bet it's not leupold or redfield

use blue locktite! and if that does not work get a good mount like a leupold or redfield.

Others have suggested Loctite, and this is a good step.  

I would recommend using a proper sized screwdriver head to tighten the screws.  It's amazing how much more securely you can tighten things down when your screwdriver fits.  If you have allen screws, obviously this doesn't apply; either the hex key fits or it doesn't.  

I have usually never needed Loctite on my actual rings, but it's a necessity on the mount.  It just sounds like you're not cranking down on the rings enough.  

Weld the scope on to the mount or use some of that unremovable-cape-buffalo-dung (R) (UCBD) (TM). Works like a charm....

Doggonit

Just got a torque wrench.

What is a good torque setting for the scope ring screws?

25 inch/lb.?

Quoted: 45-65 INCH/pounds (NOT FOOT/pounds!). -Troy

45-65 inch/lb. for the screws that tighten the rings onto the scope?

Or 45-65 inch/lb. to screw in the rings to the base?

I'm using the ARMS #22 30mm rings.

Get some badger rings and base.  Loctite the base to the action, torque the rings to 65in pounds.

Quoted: Get some badger rings and base.  Loctite the base to the action, torque the rings to 65in pounds.

I have the badger base on my 700P LTR.
Badger Ordinance told me 15-18 inch/lb. for the base screws.

I'm keeping the ARMS #22 30mm rings for now.  And I was thinking around 20 inch/lb. for the screws that fasten the scope...what do you think?

badgers, badgers,

we don't need no stinking badgers!!!

I've been struggling a lot with this problem lately and have been doing some reading and talking on other boards and have come to the following conclusions.  After much debate I have decided NOT to use locktite for the following reasons: 1) locktite sets up very quickly, too quickly at times, sometimes in about five seconds.  This is is insufficient time for proper torqueing of the screws on a scope.  You need to torque the screws and then go back and re-torque them again.  As you tighten some screws the other ones become somewhat loosened and need to be torqued tighter.  You can't do this with locktite.  If you do use locktite you'll just be torqueing against the locktite instead of tightening the screws.  2.)  After shooting your rifle with your newly mounted scope, you're gonna need to re-torque all of your screws again.  Believe it or not, the shock of just a couple rounds on a newly placed scope may bring forth the need for tightening.  3.)  with changing weather conditions your screws will expanding and contract with heating and cooling cycles (such as outside to hunt during deer season in the winter, and then bringing the rifle back inside at the end of the day).  4.)  If you ever want to change your scope you're gonna have this locktite crud spread all over the screws and everything, making a real mess to clean up.  5.)  If you put just a little too much  locktite on the screw, you're not gonna be able to set the screw deeply enough in the hole becasue the locktite fills the gap and prevents the metal to metal contact which you need to secure the screw tightly.

So basically I've resigned my self to always having to re-torque my scope rings/screws.  Much more often in my magnum calibers, and not as often in my AR.  Get  yourself a good torque handle and torque screw-driver.

just try the locktite.
once you do you will see it was a no brainer.
most or the torquing and re torquing you are talking about is not nessesery.  when you apply the locktite you have ath the minimum 60 seconds but it will not fully cure for 24 hrs.

You know last week I just mounted a scope on my new 375 H&H Grizzly Gun.  Torqued the screws very well with a torque wrench.  Took it out and fired about a half dozen rounds (holy $hit).  Tooke it home and six of the eight screws upon re-torueing moved about 1/8 to 1/16 of a revolution.  Now, if I had locktited them I'm not sure if they would have been loose or not.  Either the screws are backing out, or they are settling in.  If the screws are backing out then the locktite would help solve that problem.  If the screws are setting in then the locktite would screw-up (no pun intended) the problem by hindering further tightening of them.  I THINK that it's that screws settle in with repeated firing; more with big magnums, and less with smaller calibers.  I had a scope mount come loose in the form of scope rotation on a 416 Rigby last year.  I think that sometimes the shockwave just breaks down the locktite.