Home Forums Hunting & Shooting Ask The Gunwriters Bore sighters

I have several and keep turning to the Bushnell; Leupold has one that just doesn't work as well.

MD,

Can you recall which collimators can be adjusted so the reticle of a sighted-in rifle is centered on the collimator screen?

Thanks.

Can the spud style collimator damage the barrel?

I suppose it could if one was careless. The spud is undersized with a little spring loaded wire that holds the spud in, at least that is what the BSA models use. No adjustments for the collimator.

The spring loaded wire is brass on my set. It shouldn’t hurt anything.

I've never seen any damage in a bore-scope.

The Bushnell I've had for 40 years now can be adjusted. Dunno about the latest models.

Does Bushnell still make the model with the spuds and if so where to purchase such item?

I'd try Brownells or contact Bushnell directly.

Yes, they do, and price is under $100 with 4 expandable spuds (or arbors, as they call them). You can also order a kit with a bunch of bore-specific, non-expandable spuds

There are also some very good laser bore-sighters. I also have a magnetic laer from MidwayUSA that fits on the muzzle and works very well, but many are cartridge-specific models that, for instance, fit in a .30-06 chamber. They also work well, but are of course limited to rifles chambered for that round.

I look down the bore at a target, ang get on paper every time.

The OP specifically asked about AR's. While it's entirely possible to look down the bore in an AR, it involves some disassembly.

A bunch of other actions also don't allow looking down the bore while tweaking the scope.

I guess you got me there.

The key to looking down the bore is to have the upper (or the rifle) on bags or a rest or even just on a flat, solid surface in the case of an AR upper separated from the lower. It can't move between looking down the bore & twisting the knobs.

That isn't critical with lasers & collimators.

I am amazed that turret twisters aren't all about them. No better way I know of to make sure you're scope is optically centered after sighting in.

A lot of people talk about making sure the scope is centered before mounting. If you aren't using some kind of adjustable ring or mount system, it doesn't really make a hoot that I can see. Adjustments are going to end up where they need to be to get sighted in. Having the scope centered before hand may or may not make it a little easier to get on paper if you don't do some kind of bore sighting. If everything is perfect with the set-up it may help but not necessarily. I have saw two very accurate loads hit about 4 inches apart left/right of each other.

To me, a bore sighters most important use if after getting sighted in. As somebody else already stated, you can make a note of where the crosshairs end up to know at a quick glance if something has happened since you sighted in. Even more important is getting the scope centered after sighting in.

Basically, get sighted in. Take a reading of where the crosshairs are in the grid. Then optically center your scope and use your ring or base system to bring the cross hair to within a click or two of where it was on the grid after you got the initial sight in. Now your scope is mounted, very near the optical center and sighted in. It will give you the most travel up and down inside the tube if it is centered. If you later change loads and the new load is hitting significantly left or right of the original load, you may want to go through the process again, especially if you're a twister.


ymmv.

If one is into long range shooting and will twist turrets for bullet drop at long range, why would you want to optically center your reticle after zeroing in? A canted base to allow more adjustment vertically is what most do, such as a 20 MOA angled base.

I think he's talking mostly about wind.

I always thought this was self evident, but realize that the line of sight and bullet trajectory path both occur way below the bore line. A strictly bore sighted rifle is not sighted in at all, but will be usually shooting higher than needed at downrange targets. That at least has been my experience. The trajectory line crosses the line of sight twice (both times below the bore line), once in the neighborhood of 25 yards (hence usually being on paper there), again at whatever range the shooter sights in the rifle. Changing ring height will change things as well.

Unfortunately, my experience has taught me that a bore sighted rifle can shoot high, low, left or right or a combination of the preceding

As I noted in a earlier post on this thread, for the best use a collimator should be "sighted-in" by sticking it on the muzzle of several sighted-in rifles, and noting where the center of the reticle ends up on the collimator screen. That point will vary some from rifle to rifle, due to barrel contour, cartridge, etc., but you can generally come up with an average point which will be pretty close for most rifles.

Agreeed.