Arrow shafts can vary in diameter, but the grippers on most quivers are the same. I have found that some of my quivers do not hold the shafts tightly enough, and the arrows slip out or rattle around. I’d rather not risk damage to any of the grippers by screwing, pop-riveting or dismantling them, so this is the solution I use. Liquid rubber, also known as Liquid Tape, can be found in the electrical supplies at most home improvement stores.
Use a toothpick to apply a small amount of Liquid Tape to the inside of the gripper holes. It will narrow the diameter of the hole without any visible alteration or possible damage. You might have to apply more than one coat to get the desired opening size. Mistakes can be cleaned up with a wet paper towel while the rubber is still wet. The liquid rubber cures rather quickly, so this modification is fast and easy. Be sure the curing is complete before inserting arrows into the quiver.