Question about my method of sighting in scope


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sleepyone
April 20, 2013, 04:03 PM
I have always paid a gunsmith to mount and boresight my scopes for me. I decided I could start using that money for better purposes, like ammo! Today I mounted my Buckmasters 3x9 40mm scope on my Marlin 336C .30-30 and went to a local outdoor range. A good friend told me he never bore sights scopes by removing the bolt and doing it by eye or with a laser bore sight. Here is the method he has been using for decades.

He said aim your first shot at the bulls eye. After the first shot, do not move your rifle and while looking through the scope adjust it until the reticle is on the hole from the first shot and then proceed to zero it from there by shooting at the bulls eye and making your fine adjustments.

My first shot was 4" low and 5 1/2" to the left of the bulls eye. I was using a rifle rest with only one sand bag, so after my first shot my rifle and rest had jumped back and off center several inches, so I thought well that method was not going to work now since he had said not to move your rifle after the first shot.

So, instead I just adjusted my scope directly to the bulls eye. It took me 44 clicks up and 46 clicks to the right to zero it in at about 60 yards. My 3 shot group was just under an inch. My scope adjusts 1/4" per click, so I figure being 4" low to start should have only taken 16 clicks to zero my elevation instead of the 44 clicks it actually took. And being 5 1/2" left to start should only have taken 22 clicks to zero my windage instead of the 46 clicks it actually took.

What gives? Would my friend's method still have worked if I moved my rifle back into the original position as close as I could and adjusted my scope to the first shot? Would it have taken less adjustment? What is the difference between his method and what I did, and is my method just as good even though it seems like I had to make a lot more adjustment then what the numbers said I should have?

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jmr40
April 20, 2013, 04:19 PM
That method can work, if your rifle is completely locked into place. The 1/4" per click is at 100 yards, at 60 yards each click is closer to 1/8" so I'm not surprised that it took 2X as many as expected. As long as you have it zeroed now it does not matter. When you move to 100 yards you may still need to tweak it some.

With levers and other guns where I cannot see through the bore I like to either start at 25 yards, or if at 50 yards I just make sure I use a big enough target that I cannot miss. I generally only fire 1 shot at 50, then measure the distance from the bull. I like to use a sheet of graph paper for this because I can see each 1/4" grid through the scope at 50 and determine exactly how much to adjust the scope for the 2nd shot without walking to the target. Just remember that at 50 yards most scopes move point of impact 1/8", not 1/4".

After adjusting the scope I'll fire a 2nd shot and fine tune if necessary. I always move to 100 yards for shots 3-5 for my 1st 3 shot group. I'm always close enough by the 3rd shot to hit a big game animal at that range, but I may need to fine tune a bit. I shoot to at least 200 and fine tune as I go, but with a 30-30 I'd probably stop at 100. Even If I never plan to shoot past 50, I still like to zero at 100 yards because small differences at 50 yards often don't show up until you shoot from farther out.

MaterDei
April 20, 2013, 06:42 PM
Doesn't need to be locked in place. After taking the first shot the rifle WILL move. Before you start adjusting to the hole from your first shot adjust the rifle so that without touching it it is aimed at the POI of your first shot. Now adjust to the hole. You can do the same thing with iron sights, it's just harder as the POI is less precise and the hole is harder to see. :)

Good luck.

StretchNM
April 20, 2013, 07:32 PM
What you were doing wasn't, of course, "bore sighting". You were fine tuning the scope to the bullseye. It was just lucky that, after mounting your scope, it was only off by 4" and 5". That can happen alot.

Bore sighting brings the rifle and scope together quicker when the distance from POI the rifle would have been is so greeat that sometimes there isn't enough adjustment to bring it in line. But! There's virtually no way of knowing if this is going to be the case until the scope and rifle are mated and fired. This is why boresighting is so effective. It saves you from getting out to the range and finding that there's no more sdjustment in your scope to bring your combo around the way you want it.

As someone said, on some rifles you don;t have a choice. In order to boresight my Savage 99 rifles, I would have to tear the stock off and all the guts out in order to boresight by eye, which is how I do it. So, I just mount the scope the way you did yours and hope for the best. At the range I'll bring it in line with adjustment.

In my opinion, boresighting by eye or with a light or tool is the most effective way to mount a scope. At the range, you can rest assured that the rifle and scope will zero without much effort.

jgh4445
April 20, 2013, 08:08 PM
Mater Dei. I think you meant to replace the rifle on the rest just as it was when you fired the first shot and hold it steady making sure it is aimed at the same POA as it was for the first shot. then, dial the crosshairs to the POI from there. As you said it I would take it that I had to make sure it was aiming at the hole instead of the original point of aim. Or...I could be wrong......And..this is a great way to zero in. I usually do this from 25 yds. Just place the rifle on a rest, remove the bolt, make sure the scopes cross hairs are centered on the target then, without touching the rifle, lower your head and look thru the barrel at the target. Keep making small adjustments until it looks like the cross hair and the CENTER of the bore are both aimed at the same place on the target. Then, put the bolt back in and fire that first shot. After dialing the scope to the hole, you are ready to move on to the 100 yd range. You will be close.

Another thing that helps( I think) is, when you mount the scope and get it straight, level and tightened down, turn both the windage and elevation turret knobs all the way in one direction ( say, turn the windage knob all the way to the right and the elevation knob all the way up) until the knobs stop. Then, go back the other way ONE CLICK AT A TIME, COUNTING EACH CLICK until it stops again. Now divide the number of clicks it took to get to the end by 2 and turn that many clicks again, in the opposite direction. Do this for both knobs and you will have your adjustments centered. This is helpful on a scope that is being moved from one rifle to another where the mounting system on the former rifle could have had your scope adjustments near maxed out.

Coltdriver
April 20, 2013, 08:18 PM
Nothing wrong with that approach. I have an 1895 and I just dropped the lever and pulled the bolt and used the eyeball approach to center the scope. But I start that way at 100 yards and getting on paper has never been a problem.

If you start with a reasonably centered scope you may be able to make your method work every time. At 100 yards you could easily miss the target entirely. So if you do this again do center your windage and elevation so you have a better chance of being close on first shot.

If it works who cares how you get there? I personally would never ever pay anyone to mount or bore sight a scope for me. Half of the fun is doing it yourself and understanding your set up.

sleepyone
April 21, 2013, 01:30 AM
The 1/4" per click is at 100 yards, at 60 yards each click is closer to 1/8"

That's true. I forgot about that. I actually started around 40 yards to make sure I hit paper and then moved back to the end of the range to continue once I got close to bull. This is a small outdoor range a friend has that may be 70 yards total.

My main concern with the way I did it was that I had used too much of the scope's adjustment to sight it in. I know there is a tube (erector tube?) and a spring that move when adjusting the knobs and it seems like if you had to crank it too much in any direction it would put a lot of tension/pressure on those parts.

Another thing that helps( I think) is, when you mount the scope and get it straight, level and tightened down, turn both the windage and elevation turret knobs all the way in one direction ( say, turn the windage knob all the way to the right and the elevation knob all the way up) until the knobs stop. Then, go back the other way ONE CLICK AT A TIME, COUNTING EACH CLICK until it stops again. Now divide the number of clicks it took to get to the end by 2 and turn that many clicks again, in the opposite direction. Do this for both knobs and you will have your adjustments centered. This is helpful on a scope that is being moved from one rifle to another where the mounting system on the former rifle could have had your scope adjustments near maxed out.

I did this on another Buckmasters scope I was having problems with and was shocked at how much total range of adjustment there was. It took 177 total clicks from end to end for each knob, which is almost 90 each way, so I guess I have plenty of adjustment left in mine.

Bushpilot
April 21, 2013, 10:11 AM
With levers and other guns where I cannot see through the bore I like to either start at 25 yards, or if at 50 yards I just make sure I use a big enough target that I cannot miss. I generally only fire 1 shot at 50, then measure the distance from the bull. I like to use a sheet of graph paper for this because I can see each 1/4" grid through the scope at 50 and determine exactly how much to adjust the scope for the 2nd shot without walking to the target.

jmr40, Just how big of a scope are you putting on these lever guns that you can actually see the grids on 1/4" graph paper at 50 yards well enough to count them??? I have 20/15 vision and had a tough enough time counting the grids on 1/4 inch graph paper through my 20X-60 x 60mm spotting scope at 25 yds let alone through a rifle scope at 50 yards... If I embolden every 4th line with a black Sharpie it helps but still... Hmmmn....????? Me thinks there maybe something amiss here....

Sleepyone, you could buy a piece cardboard thats BIG enough that you can't possibly miss and cover it with graph paper (???). Then start shooting at 25, then move your target to 50, then to 100 and sight in your rifle that way.... OR, you cold try and hold your rifle perfectly still while you adjust windage and elevation to move your cross hairs from the bullseye to the bullet hole. (good luck with out a shooting vise). OR, you could just spend $35 on a bore sighter, shoot a couple shoots at your 100 yard target and be done with it....

gamestalker
April 21, 2013, 06:20 PM
All I've ever done is shoot a round at 50 yds., make scope adjustment, then step out to 100 yds. make another adjustment, and so on until I'm shooting dead on at 200 yds.. Each click represents a fixed degree of cross hair movement, so if you have paper that is segregated into 1" squares you can quickly determine how many clicks in a certain direction will bring it in to zero. It shouldn't take more than several shots to accurately zero if you use this method.

As for bore sighting, it of no use to me. I have seen many hunters come in and bore sight and then miss game at 100 yds., then come back into the store all upset because the scope was not bore sighted properly. Bore sighting will only get the rifle on paper, if that, at 50 yds., if that. It is a useless means of sighting in to me.

Nothing beats a standard shoot and adjust method. And your method of trying to move the cross hairs up, down, or other wise, while looking through the scope will not work unless that rifle is absolutely and totally locked into a gun vise. And even then, it is not a practical means of sighting in your gun.
GS

ThePenguinKnight
April 21, 2013, 07:09 PM
https://www.youtube.com/watch?v=TiOpQY2ORo4&feature=youtube_gdata_player

It normally takes at least one or two more shots, but this video from NSSF demonstrates it pretty well.

Get a solid rest, front and back, so that you can leave the rifle sit without it moving. Take the first shot. Move the rifle back so that it is aiming at the exact same place as the shot you just fired (center of the bull, normally). Without letting the rifle move, use the scopes adjustments to move the reticle in the scope to where you see a bullet hole. Now the bullet should go where the reticle is pointing.

Boresighting is great whenever possible, as mentioned above. Factory irons can help you get pretty close too. Anything to save ammo for more enjoyable tasks like actual practice, since it's rather pricey these days.

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