When I was younger I always loved to perform sight-ins for firearms. I was young and not as smart as I am now so I thought I'd share some of my mistakes so I can save you time and money with your sight-ins.
So for this purpose we are going to use a rifle as a reference.
So you have your rifle with its brand new scope all mounted up and ready for dialing in! Exciting time and fun is about to be had! Number 1 mistake made.... You put a round in the camber and let one fly at the 100 yard target! All you did was cost yourself the cost of that round! I have made that $4.00 mistake many times. Please, don't waste your time, money, or cold barrel accuracy!
Step 1, after you have your scope mounted and range ready...... BORE SIGHT!! Simple and an easy process. This can be done with modern day electronics or with the right rifle, it can be done at the range with little effort! Laser bore sight tools are easy to use and when used correctly, very effective at saving you money in ammo cost. Now let's say that you have a bolt gun and you do not have access to a laser bore sight tool. This will take us to step 2.
Step 2, Go to the 25 yard handgun range! Yup, that's right, start at the handgun range. Use a SOLID rest! Remember, we are sighting in not practicing! Use a bench rest vise like a lead sled or similar. Okay, so we are getting laughed at because we have a 7mm magnum hunting rifle at the handgun range! Let them laugh!! So we have our rifle mounted and secured. Remove the bolt and look down the chamber. Center the bullseye of you target with what you see looking down the barrel.
This is what it looks like if you were at 100 yards. This is why you go to the handgun range!
Once you are centered through the barrel, change you view to the scope and adjust the scope to the same point of impact seen through the barrel. Now you are bore sighted.
I then will move to the 50 yard range and that is where I finally discharge the rifle. I will usually take two shots at this range, making an adjustment after the first shot. I want my windage to be centered and my elevation to be an inch or two high. From there I will move to the 100 yard range and finish my sight-in.
Solid and stable bench rest, use staging to bore site, and test fire. You will be able to get your rifle sighted in with a lot of extra money in your pocket. Follow these steps and you can achieve zero within 5 rounds! Save your ammo for practice shooting and don't blow it at sight-in!