KraigWY before making contact with the recoil pad on your rifle do you ensure all the air is out of your lungs?
I breath, I don't force air out of my lungs. I breath naturally. Breathing while shooting is not different then breathing while walking, setting, driving a truck. I just breath. Sometimes a little faster then others but I breath.
Lets say I'm going to shoot prone, (but its the same for all positions). I drop into position, being a right handed shooter I tend to fall on my left side and roll a tad to my right as I bring the stock to my shoulder and put my face on the stock.
I look at the target through the sights, if its right or left of my I pivot on my belt bucket until I'm lined up windage wise. Now as I breath NORMALLY, I observe my sights elevation wise. As I breath in and out, I see that the rifle is raising up and down through the target. I adjust my elevation by sliding my left or support hand back and forth under the stock until I have my perfect NPA at the bottom of my breathing cycle. I have the position adjusted that at the bottom of this breathing cycle the rifle doesn't drop any lower, it will raise up as I breath in, but it wont go lower then it will be at the longest pause of my breathing cycle, which is just before I take in air again.
As one naturally breaths the body is normally at its most relaxed state at the end of this breathing cycle, do I don't have to worry about holding the rifle during follow through. That is done automatically and at a point where the rifle stays lined up on my NPA, meaning zero muscling.
Because I'm breathing naturally, I don't have to concentrate or think about breathing, no more then I think about breathing when I'm watching TV reading or driving down the road.
This process really helps in rapid fire, once set the rifle is going to raise up and down with your breath, and as you drop down to your natural point of aim, during the bottom of the breathing cycle, you let the hammer fall, during recoil (if your shooting a gas gun) you're breathing in and out and should be out as you recover from recoil and again at the bottom of the cycle (the natural pause) you're back to your NPA, and drop the hammer again. You don't really have to think about it, because everything stops automatically and you have your NPA at the same time.
If you're shooting slower, you may or not get the shot off during the relaxed state, then don't shoot, keep breathing and catch the next point of you cycle.
Many will say this doesn't work if under stress or when winded. I disagree, you breath anyway, though you will be breathing faster, which also means you can shoot faster. A good example is shooting an Infantry Trophy match. You start out running two miles, then go to the line and you have 50 seconds to shoot as many rounds as possible. You are going to be breathing faster unless you are a machine.
Same thing while hunting. You climb a ridge, see your critter and you may or may not have a lot of time, plus you are out of breath (or at least I am) after climbing the ridge, you're going to be breathing faster. Don't worry about it, it may take a couple breaths before you are ready to shoot, but you still shoot at the bottom of the breathing which is going to be at the longest pause in natural breathing.
I hate the term "expel your breath" that indicates a conscience effort to force the air out of you lungs. That's not what we want, we want natural, we want to be relaxed.
I know I'm not making myself clear, this is why I like one on one coaching. Easier to show instead of telling it. Plus the whole process takes a heck of a lot less time doing then telling about it.
One should be able to start standing, drop in position, drop the bolt, get the elevation set, fire two rounds, check the spotting scope to see the bullet holes while loading the second mag, Make corrections or sight adjustments and fire the second mag of 8 rounds, cleaning the 200 yard rapid fire target, in about 45 seconds. Or I did any way when I was really heavy into High Power. Sight alignment will get you before your breathing does.