The only problem I’ve had with mine is if I don’t tighten the head properly it will flicker in low mode until I untwist and retwist the head. Then contact seems to be good and all is well. I also have no issue with the contacts getting scratched. Try cleaning the threads really well on both the battery tube and head. I then lubed mine with a few drops of Singer sewing machine oil. Works really well without the gumming up the silicone paste sometimes gets.