Put fully loaded mag in your gun, don't rack the slide, turn holster upside down, adjust so that gun doesn't fall out, that's it.
Why?
Seriously there is no retention level requirement anymore. Once upon a time you could be required to do an 18" standing jump or a somersault to prove retention, but those rules have been gone for years.
The relevant rules are:
5.2.6. IPSC Handgun matches will not require the use of a particular type or
brand of holster. However, the Range Master may deem that a
competitor’s holster is unsafe and order that it be improved to his
satisfaction, failing which it must be withdrawn from the match.
5.2.7. Competitors must not be permitted to commence a course of fire wearing:
5.2.7.1. A shoulder holster or "tie-down" rig (visible or otherwise),
except as specified in Rule 5.2.8,
5.2.7.2. A holster with the heel of the butt of the handgun below the top
of the belt, except as specified in Rule 5.2.8,
5.2.7.3. A holster with the muzzle of the handgun pointing further than
1 meter from the competitor's feet while standing relaxed,
5.2.7.4. A holster which does not completely prevent access to, or
activation of, the trigger of the handgun while holstered.
and in case it falls out during a CoF:
10.5.3. If at any time during the course of fire, a competitor drops his firearm or
causes it to fall, loaded or not. Note that a competitor who, for any reason
during a course of fire, safely and intentionally places the firearm on the
ground or other stable object will not be disqualified provided:
10.5.3.1. The competitor maintains constant physical contact with the
firearm, until it is placed firmly and securely on the ground or
another stable object, and
10.5.3.2. The competitor remains within 1 meter of the firearm at all
times (except where the firearm is placed at a greater distance,
under the supervision of a Range Official, in order to comply
with a start position), and
10.5.3.3. The provisions of Rule 10.5.2 do not occur, and
10.5.3.4. The handgun is in the ready condition as specified in Section
8.1, or
10.5.3.5. A self-loading pistol has the magazine removed and the slide
locked open, or
10.5.3.6. A revolver has the cylinder open and empty.
So basically there are no rules regarding retention, as long as it meets the rules laid out in 5.2.6 the holster is GTG....and if it falls out during a CoF, you are going to be DQ'd. If it falls out any other time, you must get an RO to retrieve it and then you get to clean and check for any broken parts. The onus for retention is on the shooter, as long as you are comfortable performing any tasks laid out in a CoF without dropping it then its all good. If you find you are having to clean and replace parts on a frequent basis because the damn thing won't stay in there, and RO's are getting tired of retrieveing your gun...you might want to look after that.
I have seen quite a few shooters who have either unintentionally not adjusted their holster properly or have done so thinking they will get a quicker draw (you won't) lose their guns all too frequently.
