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School me on Boresights

1805 Views 9 Replies 8 Participants Last post by  BeRzErKaS
Newb here, looking to zero in my rimfire specific scope on my Marlin 795 (its A Bushnell 3-9x*32 rimfire edition) and in the future my AR build.

What is a boresight, how is it used, can you buy the $25 one and get the job done? How much space is required, other tools, etc?
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there are many different borresight units. they all atach to the barrel and you line up your scope with the mark made with the boresighter.  then you go to range and shoot the firearm to zero the firearm. the boresighter is only to get you on paper hopefully. if you have any other question as me. without the boresiter you can go to the range and bench closely to see where you are hitting then ajust --old fashon but still works.
A boresight is used to make raw mods on a sight. It is used for proper positioning to line up the barrel with the sights. It makes zeroing in your rifle quicker.

I also obtained this info to clarify the different methods used:

"Traditional boresighting, as the name suggests involves removing the bolt and sighting down the bore of a gun to a fixed point. While the rifle is fixed in place, the scope or irons can then be adjusted to also aim at the distant object. A more modern method of boresighting is to use a laser to illuminate the distant point, rather than by visual inspection. This method is preferable because it allows more movement in the gun, as the laser dot will not move relative to the barrel, and is a method of boresighting which does not require the removal of the bolt.

A more advanced method of boresighting uses a collimator, an optic attachment similar to a scope sight, which fits onto the end of the barrel. Using this method, the normal sight (which is fixed to the stock) and the collimator (which is fixed to the barrel) can be sighted to match. Most collimators have grid patterns for rechecking the zero after the barrel is sighted.

As laser technology has become less expensive, laser bore sighters have become popular for sighting in rifles. One type of laser bore sight is inserted into the chamber, and projects a beam through the barrel onto the target. The user then adjusts the rifle scope until the crosshairs are on the laser dot. Another type of laser bore sighter is more universal, and is attached to the end of the barrel. It is held in alignment with the barrel and projects a laser beam onto the target. Again, the user aligns the crosshairs to the laser dot on the target."
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excellent write up robyn!

i use a bushnell collimator...it was like 50 bucks brand new and has a super strong magnet...stick it on the front of the barrel, about even with your scope, point at a light source and adjust until your crosshairs are on center...then take the rifle to the 100yd range and make any fine adjustments needed to zero it in on paper...
Just make sure you take the boresighter out before you fire the weapon.  
In Colorado, I dropped the rifle from the horse, and it rolled and slid down a nice steep embankment. My Zeiss scope seemed intact, but was no longer shooting to zero. We built a brace out of a log. Shot the gun and then moved the scope to line up with the bullet hole. Worked like a house on fire.

Since then, I zeroed in 2 different scopes, the very same way. 2 bullets. Done!!

By the way, I have a 25 year old Bushnell bore sighter that slides into the barrel. If you want to meet up and bore sight your rifle, let me know.
Thanks for the replies. Well for now this is just for my Marlin 795 (.22lr). I went to Mitchell, put the target all the way out, and was hitting paper, just not where I wanted to. Granted Mitchell is what 30 yards max?

Anyway, if I am on paper, should I just use the scope adjustment to get it zerod. Obviously the rounds don't cost much and I find that fun, but I figured if there was a way to quickly get it on point, that might be cool too.

Now when it comes time to do my AR, maybe then I will boresight.
BirdistheWord said:
Thanks for the replies. Well for now this is just for my Marlin 795 (.22lr). I went to Mitchell, put the target all the way out, and was hitting paper, just not where I wanted to. Granted Mitchell is what 30 yards max?

Anyway, if I am on paper, should I just use the scope adjustment to get it zerod. Obviously the rounds don't cost much and I find that fun, but I figured if there was a way to quickly get it on point, that might be cool too.

Now when it comes time to do my AR, maybe then I will boresight.
Just move the scope until you're an inch or 2 high at 25 yards. Don't forget to let the barrel cool down between shots. this last piece of advice is far more important when you start shooting bigger bores.
I brought my 30-30 to Camp Site in Huntington Station, the guy there did it for me...pretty painless.
FWIW, you don't need a boresighter to get an AR on paper.

Just separate the upper and lower, remove the BCG and peep through the barrel from reciever to muzzle. Then adjust the scope accordingly. When the sight pictures are the same through the barrel and the scope you are in the right ballpark. It helps if you set the upper on a stand or on sandbags so it remains stationary.

After that you should have her fine tuned within three rounds.
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