Bought these for my revolvers, wife's semi auto's and rifles. They lock on all of them. DO they stop the gun from firing? Not on a single one of the 11 firearms we tried them on. As I said yes the locks lock. The issue is with the post. It does not fit behind the triggers it fits in front of them and wit enough slack that with minimal effort (our 5 year old grandson can fire the weapons) . Now before you go off on how unsafe it is for him to do so it was a test. Controlled and with empty guns we are not idiots. After all it is the kids that will pay the price for this lock not working.
We took them to the gunsmith and the same thing. He recommended throwing them in the trash because he has never been able to make one work. EVEN Master Lock themselves could not give one single example of a gun these would actually fit well . The fine print that comes with the locks state the same basic thing. Folks there are much better locks out there for the same or a bit more money. If you have a magazine type that a cable lock will fit that is a much better idea for them. Look for a lock that has two posts, one to fit in front of the trigger and the second to fit behind the trigger immobilizing the trigger itself.  A gun case is important as well however if you have the weapon for home defense you cannot actually keep it unloaded in a case or safe and actually think you would be able to get it out and loaded before the bad guys get to you or your family. I believe after a break in the average time you have to be prepared to fire and defend yourself or family is 4 SECONDS. Have something that will allow you to defend AND secure the firearm. Herters has a nice electronic safe that will pop open instantly with a wrist bracelet or finger print. Many other examples out there as well but please, If you need a trigger guard for local rules then find something that will actually secure your weapon and not just look like it's secured. The life you save may be your own or a family members.
Bought these for my revolvers, wife's semi auto's and rifles. They lock on all of them. DO they stop the gun from firing? Not on a single one of the 11 firearms we tried them on. As I said yes the locks lock. The issue is with the post. It does not fit behind the triggers it fits in front of them and wit enough slack that with minimal effort (our 5 year old grandson can fire the weapons). Now before you go off on how unsafe it is for him to do so it was a test. Controlled and with empty guns we are not idiots. After all it is the kids that will pay the price for this lock not working. We took them to the gunsmith and the same thing. He recommended throwing them in the trash because he has never been able to make one work. EVEN Master Lock themselves could not give one single example of a gun these would actually fit well. The fine print that comes with the locks state the same basic thing. Folks there are much better locks out there for the same or a bit more money. If you have a magazine type that a cable lock will fit that is a much better idea for them. Look for a lock that has two posts, one to fit in front of the trigger and the second to fit behind the trigger immobilizing the trigger itself. A gun case is important as well however if you have the weapon for home defense you cannot actually keep it unloaded in a case or safe and actually think you would be able to get it out and loaded before the bad guys get to you or your family. I believe after a break in the average time you have to be prepared to fire and defend yourself or family is 4 SECONDS. Have something that will allow you to defend AND secure the firearm. Herters has a nice electronic safe that will pop open instantly with a wrist bracelet or finger print. Many other examples out there as well but please, If you need a trigger guard for local rules then find something that will actually secure your weapon and not just look like it's secured. The life you save may be your own or a family members.