Re: Shooting between heartbeats??
When I shot rifle (smallbore) in college, the coach (MSG Driscoll...) had us practice 'biofeedback' as it was called back then. That set of exercises supposedly helped slow heartrate and regulate breathing. I thought it was a bunch of bovine scatology then, but he was the coach.
Realistically, I think what we were doing was practicing relaxation and breathing. But there was supposed to be a whole science behind it and the coach was a proponant. So call it what you will... he said 'do it.' We did it.
That said, if you work on some relaxation techniques and breath control, it does help, especially at long ranges and at shorter ranges can really tighten group sizes.
At high magnifications (and especially when you have a good cheek weld), you can see the reticle bounce with heartbeats, just as mgd45 says.
As you get familiar with your trigger release point, you can time the trigger break to the rhythm of your breath/heartbeat.
This is one of the real values of dry fire training. Because you don't need a round downrange to know if your break was 'timed' nicely.
FYI, on stress courses, the ability to get 'in your zone' quickly is really valuable. Ignoring the stressors (usually obstacles and people yelling at you) is part of it. But if you are running and doing obstacles, etc. it can be well worth waiting a few seconds to relax and get in you happy place before firing your shot. In competition, you are doing the math between your timed speed and the X ring. If you are working in the real world, you need to make sure that your shot is on target, period. Knowing your own physiology and how it will affect a shot matters in both cases.
Finally... if you are shooting really long range courses, which I don't do much, your physiology is going to be a lot less valuable than your ability to read wind, environmental conditions, etc. This is where your databook (and range time) are priceless. Every little thing helps, though.
Hope this gives some insight... I am sure others here will have more to add. But this may give you a start.
Cheers,
Sirhr
