How do you bore sight/sight-in? raised scope & irons?

[Ervin]

I've been here a very short time, but long enough to
learn that I have much more to learn.
I find that interesting since I am anything but a stranger
to firearms, and internet forums too for that matter.
Interesting, but not a mystery...
The absence of sarcastic bullying
(under the guise of "dry humor")
creates an atmosphere conducive with
constructive, informative exchange.
I like to toss a rock at a friend's head now and then,
but not at the new kid trying to get acclimated.

Now, I alluded to this in my (first ever) post in the
(or any) new member introduction section, so I will stop now
and ramble no more about the well-bred, civilized tone
of this board's membership.

Question:
When aligning iron sights with red dot, non magnified
optics. Is it of any ammo-saving advantage to use a
bore sighter? It's an inexpensive one in the $40 range
that I've never used, so that's just not familiar to me.
So far I've adjusted the red dot until
the iron sights have the illuminated dot in their center.
Would a bore sighter get me closer to zero than I am
right now, and if so, what steps should I take prior to
the test shots?

 

[oneyeopn]

I use a bushnell boresighter. I try to get as much distance at least 50 yards to sight in to. You install the boresight with the correct bushing so that it tightens up in the barrel and is as tight against the muzzle as you can get it, I try to twist the laser in the barrel watching it on the wall I am using until I get it as well centered as I can and then make sure my sights line up with the red dot on the wall I am using to boresight with. What this does for me is when I go to shoot, my first shots are on the target and I then do the fine adjustments to where my bullet hits exactly where my sights are pointed at. It saves me 3 to 12 shots when sighting in. While I was building my rifle and changing it often it allowed me to start pretty well on the target everytime.

 

[TangoFoxtrot]

First of all welcome to the forum. Secondly you can rest easy knowing there are no bullies here only helpful nice people who enjoy their firearms and good conversation. I know the internet sights you speal of.LOL

With that being said Oneyopn stated it best. I used my Bushnell bore sighter as well to set my red dot before I started firing rounds, just like I did for my BUIS.

 

[JWS3]

I have never used a bore-sighting device during zero. All I've ever done is set the BUIS to mechanical zero and then carefully fire my shot groups. It normally takes me around 9 to 12 rounds to perform the zero. After that, I just indexed the dot on my Eotech XPS to the front sight and confirmed the shot placement. An additional 3 to 6 rounds are used for confirmation.

 

[storeyteller]

Question:
When aligning iron sights with red dot, non magnified
optics. Is it of any ammo-saving advantage to use a
bore sighter? It's an inexpensive one in the $40 range
that I've never used, so that's just not familiar to me.
So far I've adjusted the red dot until
the iron sights have the illuminated dot in their center.
Would a bore sighter get me closer to zero than I am
right now, and if so, what steps should I take prior to
the test shots?

I assume the BUIS have already been zeroed and you are now just lining up the red dot with 'em..? If that is the case go shoot it. Should be close if not on. If not zero the BUIS first, then line up the red dot and shoot it.
I have a boresight that I use with varying degrees of success on a number of scoped rifles, but have never used one with irons.

 

[JaPes]

I use a Bushnell bore sighter like this one:

It gets me on paper. I then use a process similar to the video referenced below to set a mechanical zero on my irons. It takes 3 to 4 rounds to zero.

How to Zero your AR15 / M4 / M16A2 Platform: Mechanical Zero & the 25m Target - YouTube

When I get my irons sighted in, I'll zero my dot to the irons.

Done.

 

[Ervin]

I assume the BUIS have already been zeroed and you are now just lining up the red dot with 'em..? If that is the case go shoot it. Should be close if not on. If not zero the BUIS first, then line up the red dot and shoot it.
I have a boresight that I use with varying degrees of success on a number of scoped rifles, but have never used one with irons.

Good point. I failed to mention the BUIS,
because I forgot to check it again after changing optics.
I'll start there before the bore sight. Thank you!

 

[Ervin]

While I was building my rifle and changing it often it allowed me to start pretty well on the target everytime.

Thanks for your help. Changing optics/swapping
out equipment is why I bought the bore sight,
and I hear you do this quite often. LOL

 

[oneyeopn]

I have also used a boresight with iron sights and it does help.
LMAO Yeah I have been known to make a couple of drastic changes in a week or less, but as you well know its not done until its done

 

[VMaxSplat]

Question:
When aligning iron sights with red dot, non magnified
optics. Is it of any ammo-saving advantage to use a
bore sighter? It's an inexpensive one in the $40 range
that I've never used, so that's just not familiar to me.
So far I've adjusted the red dot until
the iron sights have the illuminated dot in their center.
Would a bore sighter get me closer to zero than I am
right now, and if so, what steps should I take prior to
the test shots?

This may be more info than you want, but I'd suggest adjusting the irons first. BTW, I am a big fan of the "same plane" rear apertures over the standard military AR aperture. Adjust the front sight for elevation and the rear for windage. My suggestion is a good 50 yard zero. This will give you a good point blank range of 250 yards with M193 type ammo.

Once the irons are on zero, adjust the cowitnessed red dot so that the dot is at the tip of the front sight when you have a normal sight picture thru the irons. This is going to be close enough to shoot verification groups with the dot at 50 yards. Refine the optics zero as needed from there.

 

[arizona98tj]

I am old fashioned when it comes to sighting in a rifle. Assuming one can look down the barrel from the receiver (AR-15 falls into this category), I'll put the rifle (or upper in the case of the AR) on a sandbag and adjust the sight/optic to coincide with the target I see through the barrel. My last optic mounting project, on my bolt gun.....the first shot at 50 yards hit the 1" bullseye. From there, I moved back to 100 yds and finished dialing adjusting the optic. I used the same method when I installed my ACOG on my M&P15 OR. Now, if you can't see through the barrel, such as with my FNAR, then this method doesn't work. In that case, I start at 25 yds and work back to 100 yds. It typically takes an extra half dozen rounds to get to the same zero compared to the first method.

 

[storeyteller]

I am old fashioned when it comes to sighting in a rifle. Assuming one can look down the barrel from the receiver (AR-15 falls into this category), I'll put the rifle (or upper in the case of the AR) on a sandbag and adjust the sight/optic to coincide with the target I see through the barrel. QUOTE]

How I was taught and continue to do until this day. I will use a laser with a bolt gun, but always check by looking down the bore (a tennis ball @ 25yds works nicely). When I tried to laser boresight the sport I just couldn't get a good fit without removing the flash hider which I don't like to do unless I have to.

 

[Ervin]

I am old fashioned when it comes to sighting in a rifle. Assuming one can look down the barrel from the receiver (AR-15 falls into this category), I'll put the rifle (or upper in the case of the AR) on a sandbag and adjust the sight/optic to coincide with the target I see through the barrel. My last optic mounting project, on my bolt gun.....the first shot at 50 yards hit the 1" bullseye. From there, I moved back to 100 yds and finished dialing adjusting the optic. I used the same method when I installed my ACOG on my M&P15 OR. Now, if you can't see through the barrel, such as with my FNAR, then this method doesn't work. In that case, I start at 25 yds and work back to 100 yds. It typically takes an extra half dozen rounds to get to the same zero compared to the first method.

Sorry, arizona, but this is entirely too simple and logical to work.



Freakin brilliant - actually. Would you believe I've never tried this method? I'm serious. Thank you for reminding me of my
of Dad (USMC) also. He always had a way of cutting through bulls**it like a hot knife through butter. I miss his advice like this.

 

[Ervin]

ADD ON question:
I want to know if you guys had trouble sighting a scope
mounted high enough to clear the raised rear sight?
I would like to keep the irons in tact.

 

[cyphertext]

I've used a bore sighter for scopes,not the laser kind, but the kind that has a piece that you align at the top of the muzzle and then you look at that piece through your scope and it shows a grid to align the cross hairs with. I've also used the look down the bore method, and both work. Both will get you on paper. Once on paper, I lock my rifle down in a sled or strongly support both the forend and the butt with sandbags and shoot a 3 shot group. Then I move the crosshairs to line up with the group.

I also keep one of these in my range bag to assist with sighting in the irons...

http://www.bobdbob.com/~deneb/doc/targets/m16a2-25m-zero.pdf

 

[storeyteller]

ADD ON question:
I want to know if you guys had trouble sighting a scope
mounted high enough to clear the raised rear sight?
I would like to keep the irons in tact.

Have sighted in scopes mounted on carry handle without any problems.

 

[arizona98tj]

ADD ON question:
I want to know if you guys had trouble sighting a scope
mounted high enough to clear the raised rear sight?
I would like to keep the irons in tact.

Compared to a setup where the centerline of the optic is as close as possible to the barrel's centerline, you will see some differences when calculating come-ups and/or holdover compensation for close up work.

I prefer to keep my optic as close to the bore as is possible.

 

[Ervin]

I've used a bore sighter for scopes,not the laser kind, but the kind that has a piece that you align at the top of the muzzle and then you look at that piece through your scope and it shows a grid to align the cross hairs with. I've also used the look down the bore method, and both work. Both will get you on paper. Once on paper, I lock my rifle down in a sled or strongly support both the forend and the butt with sandbags and shoot a 3 shot group. Then I move the crosshairs to line up with the group.

I also keep one of these in my range bag to assist with sighting in the irons...

http://www.bobdbob.com/~deneb/doc/targets/m16a2-25m-zero.pdf

cyphertext - thanks for the response.
I learned something.

 

[Dikinalaska]

I don't know if it makes a difference but my laser boresighter doesn't go into the front of the barrel. Mine looks like a spent casing that I load into the chamber and gently let my charging handle back to lock it in place. Do you guys know if this works better/worse than the end of barrel kind? I know you're limited because it's 223 specific but it works for me