I have the Benelli M2 with choke option and I do use the chokes quite a bit. First shotgun with chokes I ever had. I properly clean and lube chokes and threads after switching them and generally do all the recommended maintenance on them. I also tighten them correctly. But since the beginning I always had the problem with the chokes loosening a bit inside the barrel after about 20 to 25 shots fired. Not much, a fraction of an inch, and easily tightened again with a slight right twist.
My Question: Is this normal? Seems the continuous concussions of firing the gun slightly loosen up the chokes in the threads a bit after a while. Does anyone have a similar problem or comment on this ??