Campfire argument fodder #57

[wolfsong]

I recently purchased my first AR-15, a S&W M&P Sporter. Next, I decided on a Vortex Crossfire II with a one piece cantilever mount. Meanwhile, my good friend Jerry has built a couple of ARs including an AR-10. He went with Nikon glass.

We're in the process of putting together an informal AR shooting match with a few other shooters, and Jerry and I are determined to show the others that we are not to be trifled with. So, now it's time to mount the scopes and dial them in. This is where the argument begins.

Jerry insists that bore sighting is necessary, and a bore sighter is needed. I agree that bore sighting while mounting a scope (but before hitting the range) definitely helps, but it's still necessary to dial in and fine tune the rifle/scope combo with live fire. My contention is that just about any old bore sighter will do the trick. Jerry insists on buying a high end sighter such as the Site Lite SL100 for $100. He feels that top of the line is the best bang for the buck. I say whatever gets you on paper is just fine. $100 buys a fair amount of ammo and besides, unless you're changing scopes or barrels with some frequency, a high end set up doesn't earn its keep.

Now, granted, I have never used a bore sighter, so my opinion is based on, well, nothing. I did find that the couple of scopes I had mounted by my LGS when I was younger and dumber than I am now still had to be dialed at the range, so...

My view is mount the scopes, hit the range and do the work. Jerry's view is buy the best and gain an advantage. Or maybe he likes to spend money on toys more than I do.

Okay, let's hear what y'all have to say.

Peace and God bless, Wolfie.

 

[Pat-inCO]

Based on the last five scopes I have put on (one really "inexpensive" the rest
not so), I would go to the 25yd range with a small roll of newsprint (the local
news paper sold me one for $3). Cover the board for at least three feet, shoot
at the center and go from there. If you are on sandbags and steady, you should
have it tuned in to a small target in no more than five rounds.

After that, it's the same as if you had bore sighted.

Besides which, I break in the barrel on rifles (other than rim fire) anyway, and
using the above I'm on target and fine tuning the adjustments before I finish
the single shot string anyway.

Main point: Your gun, your ammo, do what you like. :D


P.S. Helped a friend do his .223 varmint rifle, that the LGS bore sighted for
him, and we ended up redoing it anyway (Sportsman's Warehouse).

 

[contender]

A boresighting tool can reduce time, frustration & ammo.
However, you do not have to spend a war pension on a boresighting tool. I have a ANIB kit with pilots for all calibers that I'd sell for $50.

BUT YOU DON"T ACTUALLY NEED IT!

If all you'll ever do is an occasional scope mounting, no tool is needed. Especially for an AR-15 type firearm.
First; separate the upper & lower. Remove the bolt from the upper.
Next, place the scoped upper, with the scope mounted, on a couple of sandbags. (Or you can use the Lead Sled)
The point is to get it set up pointed downrange as if shooting.

Place a target 10 ft to 25 yds, (Your choice,) in front of the gun with a small center focal point. Say, a 1/2" disc or paster.

Adjust the upper in the rest to where, you can look down the bore, at the target, and center it on the paster dot.
Then without touching the upper, adjust the crosshairs of the scope to the dot.

I like 25 yds, and when done this way, it will get you on center with the bore & the scope enough to where you can then re-assemble the gun, fire a 3 shot group at 25 yds, and adjust it accordingly.
Then move to a target at the distance you desire to be centered on, usually 100 yds. Shoot a few groups, check the group & adjust the scope. Shoot a few more until you are hitting center & the scope has settled in.

No mechanical boresighting tool necessary.

 

[Dan in MI]

I have never seen a bore sighted gun that didn't need ammo put through it to get the final sighting in done.

IMHO all a bore sighter does is get you on paper to start with. I have heard of high dollar ones that can get you back inline if you remove and replace a scope, but I have never experienced it.

About 5 years ago I bought a used .223 bolt gun. That night I mounted a scope and wanted to bore sight it. Being after dark and not having a range handy I did it in a modifed old fashioned way. Popped the bolt out and by looking through the bore got a flood light about 100 yards away center in the bore. Without touching the gun I adjusted the scope to the same flood light. The next day, when I could shoot, I was on the paper about 6" out at 100 yards.

 

[powder smoke]

Nice trick Dan! ps

 

[GRAMPS 51]

Hi what Pat-in Col said *1 figure out how high above the bore the center of the scope is generally 2 - 2 1/2" and dial in so your shooting that much low and you will be very close to 0 at 100 yds Soo many people have dealers bore sight and think they are good to go :( :(

Gramps

 

[wwb]

......... I agree that bore sighting while mounting a scope (but before hitting the range) definitely helps, but it's still necessary to dial in and fine tune the rifle/scope combo with live fire. My contention is that just about any old bore sighter will do the trick........

There it is in a nutshell.

 

[JohnBoy]

About 5 years ago I bought a used .223 bolt gun. That night I mounted a scope and wanted to bore sight it. Being after dark and not having a range handy I did it in a modifed old fashioned way. Popped the bolt out and by looking through the bore got a flood light about 100 yards away center in the bore. Without touching the gun I adjusted the scope to the same flood light. The next day, when I could shoot, I was on the paper about 6" out at 100 yards.

I do basically the same as Dan. Even if you could input load data into a bore sight tool, you would still need live fire for final tuning. Period.

I simply place an orange dot on post about 25 yards out, align scope to bore by viewing down bore - with firearm resting on sandbags, and dial in.

Now, if the rifle design is such that you can't view down the bore, this method will obviously not work. In that case, I'd mount the scope and dial in on a 25 yard target with live fire.

A person should be able to achieve alignment with very minimal ammo as there is no need to fire multiple rounds for grouping at this distance. Due to bullet trajectory, you'll find yourself very close to zero at 100 yards by sighting in at 25 yards (for most calibers//loads).

 

[Busterswoodshop]

I used to have a site-lite. I think they are more of a novelty than anything else.
The problem with them is that each caliber has a different target to be used at different ranges.
You go to their sight and print out the target you need for what caliber you want.
Then it tells you to put it at a certain range and tells you where to aim and where the laser should be.
Some of them are set so far out that you can not see the light beam unless you are inside or it is a cloudy day.
They are more hassle than they are worth in my opinion.

I bore sight my AR's by putting the upper in a vise and looking down the bore at a target of your choice.
Then I adjust the scope to the target.
Then go to the range and shoot it.
I start off at around 25 yards and work out from there.

 

[Mike J]

I have used an old mechanical bore sight tool a buddy of mine had. I have also bore sighted a bolt action rifle by removing the bolt & looking through the bore. I have never had a fancy tool. I have always had to shoot the rifle to get it just right.

Let us know how you like your Vortex scope. I bought a Vortex Diamondback a few years ago for my deer rifle & really like the glass on it. Of course the past 3 seasons (including this one) I've wound up working so much I barely get to set foot in the woods.

 

[Jimbo357mag]

A bore sight will only get you close. A large plain piece of paper and a scope or binoculars, so you can see the bullet holes, is all you really need. :D

 

[Mobuck]

I have a cheap($25 10 years ago) laser bore-siter. I use it often and find it worthwhile especially for the AR's. Most of the time, I can get first shot on a 12" x 12" target @ 100 yards by using the bore-siter @ 20 yards. The more expensive units will work at longer range in brighter light than my cheapo but that's not much of an issue.
Even w/o a bore-siter, you should be able to get a rough zero with 5 shots or less using the "big target up close" approach. In a few instances using both new scope and new rings, I've found the alignment was good enough to be "on paper" @ 100 yards w/o ANY adjustment.

 

[JFB]

I never used a bore sighter. Like mentioned, Looking through the clamped down barrel, then adjusting scope to same point use to be the way I would do.

BUT, I have become more concern with the adjustment range remaining in the scope and use the following method
1) make up a bullet drop chart for the ammo
2) put the scope in the mechancal center of its adjustments
3) verify the scope is near the optical center of adjustment with the "mirror check"
4) Fire a round on a short range target (25 or 50 yards)
5) depending upon the intended scope mounting platform, for ease, assume the mount is a normal "0" MOA; the point of impact should be the scope mounted hieght above the bore plus the drop for that range.
....for example the scope is 2" above the bore and the drop is 1" at a 50 yard target, then POI should be ~3" low.

6) if NOT within a few MOA on windage and elevation, the scope needs to be remounted.
7) dial in the MOA desired for range to be used at, noting the remaining adjustment if farther ranges may be encountered.
....for example as shown below, dial in about 10MOA for a 225 yard zero. and with the Vortex Crossfire II ample +/- 25MOA adjustment range, would leave about 15 MOA available

 

[gunman42782]

I have bore sighted literally thousands of scopes in the last 7 years working at Knob Creek. All it will do is get you on paper at 25 yards.

 

[Rick Courtright]

Hi,

I haven't mounted THAT many scopes, and only cheap ones when I did, but have "been around" the process as an observer quite often back when I was working for my old gunsmith boss.

What I've gathered from both experiences is this: one way or another it will cost you some combo of time and money to get the rifle/scope combo dialed in, and, as with so many things in life, you just get to pick the one you like best. The boresighter may save some time getting you on paper, and costs money, maybe a little, maybe a lot. Then the rifle usually still needs some fine tuning with real ammo. Not using a boresighter may cost a bit more in ammo, but some of the cost is offset by not paying for the bore sighter, and I find the time spent is more pleasant. There are plenty of folks on the Interwebs who describe methods they claim can get you all "sighted in" in as few as three shots. Maybe? Flip the coin...

For myself, various versions of the preliminary "optical boresighting" as Contender and others describe have worked well enough...

Rick C

 

[Sin6Sec63451022]

I, too, just got my first EBR AR15 setup and ready to go. I used contender's (and others) method. Now waiting for some time and weather to go shoot it. Let us know how it all works out for you guys.