Okay, I'm not able to give any sort of definitive answer for armed private citizens, as I'm mostly a LE firearms instructor and am oriented to working with cops. I've not heard of anyone teaching cops to perform "partial draws" as a "ready" technique.
Holstering & drawing are a couple of actions that can provide for some increased risk. Hesitating in the middle of either? Maybe not so good of an idea.
Why? Because we're
handling the gun (it's not resting in the holster). We work to develop skills to allow us to maximize safety and proficiency in those high-risk actions.
Drawing ... You're grasping the weapon and preparing to not only safely clear the holster, but also any cover garments, while maintaining a proper grip and trigger discipline/safety, as well as locating/positioning your
other hand to be clear of the muzzle as the weapon is presented (whether it's going to be used for support or some other, separate action) ... as well as making whatever body positioning or balance adjustments, or movement ... as may be necessary. Ever wonder why some folks are startled to find themselves fumbling their draw? Sometimes just canting the gun the wrong way, leaning off balance, or missing your "timing" during the release of a retention device
and the lifting the gun, can really throw people off.
Holstering ... Not only does the muzzle have to be located for safe insertion (not sweeping the user, or anyone else), but depending on the holster it's possible for either a retention strap, clothing (edge of jacket, shirt or drawstring) or an index finger to become trapped against the holster mouth and funneled within the trigger guard.
If you haven't seen someone experience (or experienced for yourself) getting excited and SHOVING their weapon past the front of the holster while attempting to holster, missing the holster, extending their arm & weapon downward into the air ... or, shoving it HARD into a holster, trapping their finger against the edge of the holster, shoving their finger into the trigger guard and against the trigger ... or, catching some part of their clothing inside the holster as the gun is being holstered ... or just fumbling the attempt ... you haven't experienced that sort of interesting adrenalin dump.
So ... These drawing & holstering actions are often hard enough for many folks to properly, safely & smoothly perform them under even minimal range stress conditions (if you're on a range that allows it, or are attending a class).
Creating a situation where you're "interrupting" those (hopefully) practiced & ingrained movements, hesitating partway through either movement ... and probably while under
real stress ... may create an unexpected opportunity for confusion & fumbling.
Ever hit the wrong pedal in your car, hitting the gas instead of the brakes, or the brakes instead of the gas (or, add a clutch and see some real foot action gymnastics stabbing for 1 or 2 of 3 different pedals), and that's involving actions you probably perform/practice everyday, for some years, each time you drive the car.
How about ever hesitating in applying one of them, stopping halfway and then continuing, and finding yourself doing the
opposite of what you intended? You're deviating from your normal skills application, trying to over-ride those normal actions, and sometimes a moment's confusion may make you shove your foot DOWN instead of LIFTING it (or vice versa). Hand & finger confusion, even without any jerks or "yips", can be a very unwelcome thing when we're handling guns.
Introducing an extra "step" may add to some confusion in an already unexpected, uncertain, stressful and rapidly evolving situation. That's the time when you want to keep things simple, and be able to rely on well-practiced physical movements, performed smoothly without having to stop and consciously think through each and every step of the movement. It can be even harder when your attention is distracted by a realistically perceived threat.
Also, hesitating in the drawstroke will probably require you to "re-engage" and "perform" the draw a second time, and it's not going to feel like what you normally do (when performing a complete drawstroke with the fully-holstered weapon). It might just put you behind the curve needed for the situation, too.
Now, most cops have policies, procedures and general orders regarding the drawing and presentation of their weapons in public (whether on or off-duty). I can think of some agencies that require a special report if their cops so much as grasp the butt of their holstered weapons during a public contact.
Private citizens? Well, some careful attention to your jurisdiction's use-of-force, displaying & brandishing laws might be prudent.
There's always the possibility of a chance for there to be some witness you didn't see, and we live in an age where camera phones are EVERYWHERE (except perhaps when
we need them to be there, of course
).
Just some thoughts. I apologize for the wordiness. I've just not heard someone ask about a "semi-holstered/ready" position.
