TargetTalk

I'll spare you the details but as it is I have a grip on my AP that does not belong to me until my factory replacement arrives. I can't apply Bondo/putty/quikwood so it can be returned undamaged. I'd like to (and will when I get mine) add some material at the back to stretch out my hand a little so that my index doesn't go quite so deep across the trigger shoe; Sort of, I think, what Rink grips calls "thick". Any suggestions for temporary hacks that won't mar the walnut or leave residue?
Thanks.

I don't know which AP you have, but is it possible to move the trigger forward to get that trigger finger fit?
On the Steyr system you can move the frame forward in the grip, by using the adjustment screws, or even shimming the L shaped spacer forward with cardboard.

Lacking the above, layers of moleskin can be used on the grip, but cleaning the adhesive when done should be at least mentioned to the owner.

+1 to move trigger forward
+1 for moleskin
Command Hook adhesive strips
Adhesive felt / furniture pads
Masking tape

I've used moleskin, furniture pad felt and layers of masking tape to try changes in a non-permanent way, but I didn't worry too much about cleaning the adhesive off the grip after.

I wonder about wrapping the grip in Saran wrap, then use KwikWood on top of it. Once the KwikWood cures tape the block to the grip or stick it with Command Hook adhesive. I don't know if it would be stable enough, but it might be fun to try.

Adhesive neoprene in varying thicknesses

How about shaving styrofoam to fit and holding it in place with moleskin?