Nothing should contact at the rear except the rear surface of the recoil lug. The recoil lug needs to be clear on the bottom to ensure the action is pulled down against the bed at the location of the screws.
Now, there is no way I am saying my way is always best but these are the rules for bedding I was taught fifty years ago and they have always worked. Bedding should be stress-free with contact in the appropriate places and nowhere else. The clearance at the rear of the tang is always important to prevent chipping of the stock, if nothing else. Clearance at the bottom of the lug prevent interference.
There are times when bedding the bottom of the lug is probably advisable. When the guard screw enters the lug at the front of the action, the bottom of the lug is designed as the contact point. If the screw goes into the lug, at the very front of the receiver, this is also the only time I might bed the breech end of the barrel but if there is any portion of the receiver in front of the lug, I won't bed the barrel because I have found it to frequently create a rifle which tends to shoot vertical groups. Again, all of this is my opinion only and many will vehemently disagree with it. For myself, I've been at this long enough to never say "x" is always better than "y" and if others have success with different methodology, it's pretty hard for me to argue with it. I have my theories and they have their's. GD
