TargetTalk

Im hypermobile. I have to much movement on my joints and vertebrae.
Standing rifle shooting is very stressfull for my back. Especially the vertebrae between my shoulders tend to move out of place. Which can be very painfull.
Turning in is the critical step of the stance. I already developed an open stance to limit stress.
Would a shooting jacket help support the vertebrae? Or does it mostly support lower back?

Standing rifle shooting is very stressfull for my back.

Yep, it is for all of us.

Turning in is the critical step of the stance.

What "turning"? You should not be twisting your back at all. In the past this twisting has led to several top (Olympic medalist) shooters having to undergo back surgery. About 20 or so years ago, most offhand shooters stopped the old "back bend and twist", and went to a position in which the upper body was "slid" away from the target in order to get the center of gravity of the rifle more over the hip.

You should talk to a qualified coach about your position, and a good physical therapist about what exercises to do for strengthening the torso muscles to help stabilize your back.

Everybody has to turn in otherwise you cant shoot ;)
I mean the point where you position the rifle on the hip.
I already have a stance thats very open and upright. No bending there.
Im a coach myself and my gunclub doest have any higher coaches.
Exercises dont work when yr hypermobile. Ive tried so many exercises for the muscles between my shoulderblades. But its only my arm muscles that do the work in the end. Because I have to make absurd large movements for my backmuscles even to be addressed, I have to overstretch...I cant move far enough on my own to get my back muscles to do anything..
Thats why I thought of trying a shooting jacket

Exercises do work when you’re hypermobile and they are very important to do correctly and regularly

You will not solve your problem by changing your jacket, which will only mask issues that could worsen over time. you’ll need to consider a combination of exercises and developing your position to work for you to put yourself in the best possible condition for optimal performance.

I’m happy to take a look and give you some suggestions - send me a PM to discuss further

Everybody has to turn in otherwise you cant shoot

Apparently I do not understand what you mean by "turning in". Sorry.