Boresight, two lines that never meet

[Fatal_Bert]

Bore-sighting is a convenient way to start the zeroing process, but it is not necessary. I don't even own a laser bore sighter, so I don't do it on any rifle that's not a bolt or breach action.

It is rare that a new scope is not centered on it's adjustment range from the factory, so if you mount it properly it will almost always have you on paper at 25 yards and, once again, that's all you are looking for when bore-sighting a rifle. It's also a simple matter to center the adjustment on a scope yourself.

BTW, what does the Marine Sniper Manual say about bore-sighting? Is it any different than what I'm saying in general?

It says the sight line and bore line should be parallel

 

[Bear44]

It says the sight line and bore line should be parallel

and...

 

[gh1950]

It says the sight line and bore line should be parallel

I wonder if we are talking apples and oranges here. A sporting rifle is generally sighted in at one known distance which is adequate to take game for the end of the barrel to maximum point blank range.

It seems to me that a "sniper rifle" might indeed be calibrated with parallel sight and bore lines so the the POI could be easily determined beyond MPBR, (which is slightly more than 250 yds. for most .30 cal class cartridges) and unknown distances in between. I would think that a sniper would want something smaller than the 6 inch circle which is commonly considered the "kill zone" on a deer.

 

[Redleg]

I wonder if we are talking apples and oranges here. A sporting rifle is generally sighted in at one known distance which is adequate to take game for the end of the barrel to maximum point blank range.

It seems to me that a "sniper rifle" might indeed be calibrated with parallel sight and bore lines so the the POI could be easily determined beyond MPBR, (which is slightly more than 250 yds. for most .30 cal class cartridges) and unknown distances in between. I would think that a sniper would want something smaller than the 6 inch circle which is commonly considered the "kill zone" on a deer.

Hey gh1950, thanks for the response, you are right, all depends on the intent, sporting rifle, precision rifle and the procedures followed.

 

[Bear44]

I wonder if we are talking apples and oranges here. A sporting rifle is generally sighted in at one known distance which is adequate to take game for the end of the barrel to maximum point blank range.

It seems to me that a "sniper rifle" might indeed be calibrated with parallel sight and bore lines so the the POI could be easily determined beyond MPBR, (which is slightly more than 250 yds. for most .30 cal class cartridges) and unknown distances in between. I would think that a sniper would want something smaller than the 6 inch circle which is commonly considered the "kill zone" on a deer.

Long range precision shooters (this includes snipers) will zero their rifles at a specific distance and then calculated any needed changes to point of aim or scope adjustment depending on distance and atmospheric conditions. The base zero distance may vary depending on personal preference, weapon and/or Area of Operation (AO).

I have one rifle zeroed at 100 yards (my reticle subtensions match the load very well with a 100 yard zero) and another zeroed at 500 yards (338 Lapua set up to take a shot out to 2500 yards). All others are zeroed at 200 yards. I prefer yards to meters because I prefer MOA based adjustments, rather than millirad adjustments.

I know of no long range shooter that feels a rifle is zeroed if the line of bore and line of sight are parallel.

 

[Fatal_Bert]

To be clear I was trolling when I said the manual says the lines should be parallel.

 

[Bear44]

To be clear I was trolling when I said the manual says the lines should be parallel.

I suspected, but well done. LOL!

 

[Redleg]

Long range precision shooters (this includes snipers) will zero their rifles at a specific distance and then calculated any needed changes to point of aim or scope adjustment depending on distance and atmospheric conditions. The base zero distance may vary depending on personal preference, weapon and/or Area of Operation (AO).

I have one rifle zeroed at 100 yards (my reticle subtensions match the load very well with a 100 yard zero) and another zeroed at 500 yards (338 Lapua set up to take a shot out to 2500 yards). All others are zeroed at 200 yards. I prefer yards to meters because I prefer MOA based adjustments, rather than millirad adjustments.

I know of no long range shooter that feels a rifle is zeroed if the line of bore and line of sight are parallel.

Bear44, we are saying the same in different ways, boresight is procedure that is based more on lines and the deviation from one line to another and zero the procedure based on effects of all variables accounted for as the bullets travel in a trajectory.

I agree that not all need to boresight and that a rifle is not zeroed if the line of bore and line of sight are parallel.

 

[gh1950]

I retract my earlier statements about parallel bore and sights.

On further reflection, if the bore and line of sight are truly parallel, any time the bore of the rifle is elevated (even the small amount to hit a target further down range, the sight axis would be going off into infinity - in other words it would be impossible to see the target, as the bullet would come out of the barrel parallel to the sight axis, and immediately begin dropping. Other than for a very short distance, the POI would be continuously lower (assuming the barrel is parallel to the ground.

 

[BIKER13]

all this talk will have me missing the target.Old school rules.Thanks for the edumication on lines