“But that’s not why I bought it”
You probably bought a bore sighter when you first decided to start working on guns so you could sight in a rifle without shooting it at the range. You might have decided that it wasn’t worth what you paid for it when you fired that bore sighted rifle for the first time. If you were lucky or had a big target you might have been on the paper but certainly bore sighting isn’t sighting in.
Even though the bore sighter or collimator won’t sight in your rifle it is still a big help and an ammo saver. I always bore sight first and then fire a quick shot at 25 yards to make sure I don’t waste time getting on target. When I say quick shot I mean just an offhand shot. It won’t be perfect and it doesn’t have to be. Just remember where the crosshairs were on the target and make sure your shot is where you expect it. Remember if the scope is high above the bore the bullet strike will be low at 25 yards. As a matter of fact if you use a good ballistic program you can find out where your rifle will strike at 25 or 100 yards when it is sighted in at any distant yardage. This can be a real plus when you are headed to a 600 yard match and you have a new scope on your rifle. My 308 match rifle will strike 4.5 inches high at 25 yards when it is zeroed for 600 yard shooting.
Your bore sighter will also be used after you have finished firing and have a good zero at a specific range. Say you just shot at 900 yards, it only takes a few seconds to record the bore sighter setting so next time you can confirm that you really have the rifle adjusted for 900 yards.
Now you probably already knew about bore sighters but maybe there are some other things that you can do with a collimator that hasn’t occurred to you yet. Here are a few of the neat tricks of the trade.
Checking scopes– use your bore sighter to look at the repeatability of your scope adjustments and backlash. Backlash is dead space when you are adjusting in one direction and you reverse. You are clicking right and the crosshairs are moving the correct amount each click but when you go back the other direction it clicks maybe 3 clicks before the crosshairs move. This drives good shooters up the wall in competition.
It goes something like this— You shoot and get a 10 but it is on the right side. You click one click left and shoot another 10 in the same spot. You put on another click trying to get to the X ring in the middle of the target but still hit in the same spot. Now you decide to try 2 or more clicks and get a 9 on the left side. Disgusted you move right one click and get another 9 in the same spot. If you knew you had this much backlash you would know how to adjust your scope. The bore sighter is the quickest way to find out about these internal problems in scopes.
Checking iron sights– the bore sighter will allow you to align iron sights just like a scope. It just might be a little harder to see! It can also be used to find out how high a new sight will need to be by using the bore sighter with a caliper. By holding the points of the caliper on the barrel where the front sight will go you can sight across the rear sight and adjust the caliper to center it on the bore sighter just like the caliper is a front sight. Of course it can be used the same way in place of the rear sight. If you use the same bore sighter all the time you should know where on the grid will be closer to being sighted in!
You can even use the bore sighter to check bedding–If the crosshairs move when you slacken and tighten the action screws you might need to pay some attention to your bedding. If you can push the barrel from side to side in the barrel channel and the crosshairs stops in different locations on the bore sighter it will do the same when it shoots.
Being a gunsmith is hard enough. Might as well save yourself some trouble when you can. Learning to get the most out of your tools can make your life a lot easier! Your tools will help you “Do Good Work” but they won’t do it for you!
Timothy P. Whealton