Thank you.--mostly when the toms hit. I will lower the toms and fix the problem and lower the overall drum buss, but still wondering why this happens and best way to fix.

1st adjust trim if audio, velocity if midi. If significant reduction isn't there, use a compressor or limiter across bus.If you have toms on their own tracks, start on toms so you don't squash cymbals or other pieces.

thank you for your reply. It is audio. To re-iterate, the individual drum tracks are hitting between -6db and -3db, and the sum of the drum buss  never goes above-3db, but the Master goes over. Why is that?

Make sure you have the meter settings the same for the tracks, buss and master. I once had a similar problem and it turned out that some meters were set to RMS while others were measuring peaks.

Thanks John. I thought of that--but--.
I'll check it out.

Hi:)
 
Look, if all Drum Tracks go to Drum Bus and not to Master, I've had sometimes the wrong Destination and it clips.
 
If BD, and some other Drum Hit are exactly together they are much louder than alone, so you have to move one of them a few milliseconds....
 
Perhaps you have ProChannel On on the Drum Bus with Compressor On and MakeUpd Gain..I often forgot to look if ProChannel is on on a Bus...
 
Hope it helps:)
Bassman.
 

Maybe I am just not clear, but the drum buss is fine. It is pumping at -.6db to -.3db. No problems there. I also do not use Sonar plug-ins or ProChannel. But why does the Master clip (yes, only drums are playing.)

Are your Drum buss & Master buss faders both set to 0dB (or at least set the same)?
Is the trim on the master set to 0dB?
Are there any Fx at all on your master buss?
Is the master buss set to Stereo?

ok, seems I had overlooked the bottom snare--it was going straight to the master (not via the drum buss.) (duh)Thanks everyone for all your comments and being so kind. 

Great news.