• Bushnell Professional Bore Sighter

    If you own a rifle with a scope on it, you likely either own or have used a bore sighter at some point to get a new scope on paper. There are a number of different types of bore sighters on the market these days, but most fall into one of two categories, collimators or lasers. The laser styles are fine for bore sighting, but that's all they can do. The collimator-type on the other hand can also be used for diagnostic work to verify if the scope is functioning properly. Bushnell Performance Products offers both collimator and laser bore sighters, but today we're going to focus on their #743333 Professional Bore Sighter with Case which is a collimator-type.

    When applied to the shooting world, a collimator replicates a distant target without introducing parallax to the equation. The device allows one to calibrate a rifle scope so that it is aligned with the axis of the bore by creating a target 100 yards away using just the length of a rifle barrel, a reflective surface, and a few lenses. In short, a collimator gets the scope and barrel pointed in the same direction without ever firing a shot.

    The Bushnell Professional Bore Sighter comes with three expandable arbors to cover .22-.45 caliber rifles, a fixed .17 caliber arbor, a felt-lined leather protective case and instructions. The kit sells for around $70-80 from most online vendors. Bushnell also offers a .50 Caliber to 12 Gauge Expandable Arbor (#740012) should you need to bore sight your muzzleloader or shotgun. Bushnell also offers a 15-Arbor Delux Kit (#744001) that has 15 caliber specific arbors if you don't like the expandable arbors.

    Now I know what many of you are thinking, "there's no way I'm putting mandrels in my muzzle and possibly damaging the crown." It's a valid concern, but one that's highly overblown in my opinion. As long as you take your time and pay attention to what you're doing you're not going to hurt anything. We're dealing with steel here after all - not modeling clay. For those who are adamantly against it, Bushnell offers a collimator-style Magnetic Bore Sighter (#740001C). Personally I prefer the arbor-type as I've run across more than a few factory crowns over the years that weren't cut square to the bore. The only downside to the arbor style is that it results in a fixed height so it doesn't work on firearms with the scope further from the center of the bore like an AR-type rifle.

    Bore sighting is pretty straight forward and fundamental so I'm not going to spend a lot of time explaining it here. In short, it's simply a matter of adjusting the windage and elevation so that the scope's reticle aligns with the collimator's reticle or the center of the grid. The scope and bore are then aligned, but remember that the two axis' are not parallel and will converge at some point that may or may not coincide with the bullets trajectory exactly where needed. Factors such as the scopes height above the bore and minuscule alignment errors prevent bore sighting from ever being perfect. For this reason you absolutely, positively, without exception need to fine tune your zero at the range with live ammunition.

    As eluded to earlier, there is a reason I prefer the collimator-style bore sighters and it's because they also allow me to diagnose and/or evaluate the function of a scope. But first, I should probably explain just what a collimator is and why it's beneficial.

    At some point in time every shooter is going to find him or herself questioning whether or not their scope is functioning properly. Maybe it's a new scope and you're just having a hard time getting your rifle to group well with it, or maybe it's a scope you've owned for a while and has served you well but suddenly your rifle starts shooting erratic. Whatever the case, it's all but impossible to test the mechanical function of a scope without some kind of tool - and that's where a collimator-style bore sighter such as this one from Bushnell comes into play.

    Let's say you want to know if your scope tracks properly - that when you dial in 6 clicks of elevation and two clicks of windage, that's how much it's moving. You can try to test this at the range on a target, but unless you have a very heavy rest that clamps onto the rifle, the rifle is going to move a little and make if very difficult to get a true reading. With the grid in a collimator-style bore sighter you don't have to worry about the rifle moving as it's attached to the rifle. Simply note your starting point on the grid and dial in your clicks as you watch through the scope to see the crosshair move.

    You can also in some cases use the collimator-style bore sighter to determine if something has come loose inside the scope. With the bore sighter mounted to the rifle and while looking through the scope, lightly tap on one of the turrets with the handle of a screwdriver or similar object to simulate recoil. If the reticle jumps on the grid each time you tap the scope something is loose and you will need to send it in for repair.

    Another good use of a collimater-type bore sighter is to record and periodically check your scopes zero. Let's say you are preparing to travel for a hunt and you have just zeroed the rifle with the ammunition you will be using on the trip. You can use the collimator to record your zero's position on the grid, and then upon arrival to your destination you can check to make sure the baggage handlers didn't bang your case around and disrupt it. If they did, you can easily adjust it back to where it needs to be and only need to expend one or two rounds of ammunition to verify it's back where it should be.

    The Professional Bore Sighter with Case from Bushnell is one of many of this type currently on the market from several brands, but this is the one I prefer and use myself because it has tools to adjust or "calibrate" the grid. Others are from lesser quality brands and/or are illuminated requiring batteries, and they don't offer a means to calibrate them.

    My only real complaint with this bore sighter is the fact that while the grid states that 1 square is equal to 4-inches, that isn't the case - at least not on this unit. On this unit one square is equal to thirteen 1/4 MOA clicks, or 3.25". This was verified with multiple brands of scopes of varying in magnification from 4x to 25x mounted on rifles with barrel lengths ranging from 16" to 26", and on every one it came out to 13 clicks per square. I can't say if that's just an oddity with this particular unit or if that's the norm, so all I can suggest is that you verify the actual ratio of your own if you purchase one.

    For around $75 I think it's a bargain as it's one of the most often used tools in my tool kit. The money it can save you on wasted ammunition allows it to pay for itself in short order as well.

    Contact Information
    Bushnell Outdoor Products
    9200 Cody
    Overland Park, KS 66214
    (800) 423-3537