I had one done by hanks precision gun parts a few years ago. I wish I had used his longer breach plug that lets you shoot smaller amounts of powder. They have some recoil my 15 year old knows first hand. His direct injection modules have never let me down.
Try tamping the ground and pushing them all the way in past the round z symbol. This should help if there’re pulling them up or pushing them over. I was having the same problem.