If you go to the Manufactures website, you will see that it is designed for the Ruger 10/22... nothing else. This product won't fit in anything else. It will not fit in 22 Revolvers or Ruger Mark II's. It will not fit in any other type of 22 Rifle.
You will have trouble getting it into the Ruger 10/22 and once you do, you will discover that this product is so poorly machined that it wiggles around in the chamber.
It will not stay centered in the chamber. The laser beam will actually reflect off of the inside of the barrel. Down range, you can actually watch the laser dot move 6-8 inches and more because it does not have a snug fit in the chamber.
The only thing that this device does is point in a general downrange direction of where the bullet would go.
I am a certified Rifle Instructor - If I have had to much coffee it might take me seven shots to sight it my weapon. Some students want to learn their way and at their pace and I am fine with that. Some students are like that and it seems to help them grasp what is going on. I just wanted something to help students for their skill levels. This product can not help!
With postage and restocking fees, it isn't even worth sending this product back for a refund.
I now use this product as a training aid for new students. After having the students mount the scope. The rifle is put in the vice... the student is asked to chamber the laser... and then asked if the product is steady on the target....