You may or may not be aware that you can buy a harness for the M9 holster (technically called the UM84/M12) that turns it into either a shoulder or chest rig. It you look above the flap in the photo you can see that it comes with retaining strap as well. Take the flap off and pull down the strap. That's my 5.5" redhawk in it on the left with the flap, a 1911 on the right with the strap. Nice thing about the M9 is that it is kind of universal.I carry my G20SF, when I'm hunting and hiking in a Diamond D chest rig. Quick and easy to get to and out of the way most of the time. I found an old army surplus m9 holster at a surplus store, the kind with the flap over top. I was able to alter it a little to fit my G20. It is also easy to hike with and my choice when I'm taking one of my horses for a ride.
What? You can't get your thing out far enough to see it? Just do it by feel.This has been beat to death here. Someone please insert the hammer pounding the horse avatar. That being said...
Drop leg holsters are for TV SWAT guys. Like the most uncomfortable and unpractical holster - maybe even ever. Running is impossible and the leg strap will cause your pants to ride up and pinch more than your leg if you know what I mean.
As for the chest pack, if you want to strap a fanny pack to your chest go ahead. Talk about a mess of straps and tacticool gear hanging from your pectorals this would be it. I've tried the chest holster rigs, commonly advertised for big-a$$ revolvers to be carried where scary bears live. Still have at least one for the G20. They just seem to get in the way of the pack, and jackets, and binoculars and even taking a leak (makes a big blind spot down there.)
With a day pack, I've found that a high quality, OWB, leather (not rigid kydex) pancake style holster works best. It flexes as you move and spreads the weight of the hip belt out over the gun. With a heavy pack, there's really only one option if you don't want to attach the hog leg to the pack and that's a Galco shoulder holster worn with at least one layer of clothing between the holster and your skin, and at least another layer of clothing worn between the holster and your pack. Balance the gun weight out with a flashlight and magazine(s) on the non-gun side of the shoulder holster.
If you do the belt holster route, get one that has a closed muzzle otherwise every time you sit down in the woods dirt WILL work its way into the muzzle of the gun. Trust me on this one.
I carry my pistol with me when I'm bow hunting or hiking for bear protection primarily. I'm not sure how fast you could get a weapon out if you needed to with a fanny pack. I have seen a couple of conceal carry fanny packs designed for quick deployment, but I can get to my chest holster pretty quick and I know right where it is at at all times. I wear it fairly low where it sits under the chest strap of my rucksack, but higher than my waistband. Sometimes those fanny packs shift around while you're moving.I use both the chest and waist straps on my backpack. I've found the easiest and lowest profile way to carry is an old, dorky fanny pack. I have a small canvas one from Bianchi for the PM9 and a nylon one for the FNS 40. Both have a slot for a spare mag and a pocket for snacks, med kit, etc.
I strap it on before I put on the backpack and wear it above the backpack's hip strap. I can drop the backpack and still have the fanny pack. And not one person has given it a second look when worn with the backpack.
I couldn't wear an IWB/OWB with the hip strap. On day hikes without a backpack I use an AIWB.
Sounds like I wear mine a little lower than yours. It's probably 3 inches above my hips which places it just above the hip strap. I've practiced with the same packs over the years I can get to it within the same amount of time as drawing from a concealed holster from my hip. Then the backpack itself keeps it from moving. It was very steady when we went to Red River Gorge back in September regardless of the terrain.I carry my pistol with me when I'm bow hunting or hiking for bear protection primarily. I'm not sure how fast you could get a weapon out if you needed to with a fanny pack. I have seen a couple of conceal carry fanny packs designed for quick deployment, but I can get to my chest holster pretty quick and I know right where it is at at all times. I wear it fairly low where it sits under the chest strap of my rucksack, but higher than my waistband. Sometimes those fanny packs shift around while you're moving.