dead on at 25 yds.

Dawgdad · Posted: Thu Jul 09, 2009 9:49 am Post subject: Re: dead on at 25 yds.

Okay - maybe a thread hijack or need for a new topic but here is the question...
Prefaced by a statement.

When I zero my iron sight Service rifle... I set the windage to mechanical zero or the center of the windage range from left to right. I set my elevation to a point where I can have about 2.5 moa under my 200 yard zero to allow shooting at 100 yards or changing to center of mass from six o'clock hold. I then adjust the front sight to get the point of impact to meet point of aim on a calm windless day.

The question - How many of you do a similar procedure for a scope? Do you count clicks of windage and center the reticle in the middle of the travel range? ( i.e. - if you have 100 clicks of windage from full left to full right do you spin the dial all the way left and then 50 clicks back right?)

Do you select an elevation near the bottom of the elevation adjustment that will give you a few inches of downward POI change at 100 yards but leave the majority of the elevation avaialable for long range shooting adjustments?

Up until I bought my latest Nikon with target turrets I just stuck the scope on the gun and spun the dials until it was centered up. I put a Nikon 6-18X on my 30-06 with a plan for long range (600-800 yards) sniping of call shy coyotes with 168 SMK's. I set this up the same way I do my service rifle by setting the windage and elevation dials where I wanted them to start from and then used the windage adjustable bases to set no wind zero and shimmed the rings to allow maximum elevation adjustment.

(I will need about 25 moa of the 50 moa available on the scope or 200 1/8 moa clicks at 800 yards)

chambered221 · Posted: Thu Jul 09, 2009 11:02 am Post subject: Re: dead on at 25 yds.

When ever I mount a scope I always find the mechanical center and set it prior to mounting. (usually by counting clicks like you‘ve described)
If I use the Leupold style standard bases I’ll use my bore-sighter to aid in setting and tightening the windage screws on the rear base.
On anything I set up for as a varmint gun I usually run a target turret, once zeroed at 100 yards I loosen the turret dial and zero it and record that setting.
I will then make a come-up chart for various distances based upon a combination of actual shooting, chronograghed velocity and point blank.

When dealing with long range, if needed I’d rather use the tapered bases that allows for more height adjustment than shims.
Some of the expensive long range scopes do have more elevation built into them.

Pumpkinslinger · Posted: Thu Jul 09, 2009 2:51 pm Post subject: Re: dead on at 25 yds.

I generally just mount the scope and crank in whatever correction I need. Most of my rifles have Weaver/Picatinney or Ruger bases/rings so there isn't much adjusting to be done there. I have had to shim mounts to get the scope properly aligned vertically. On this last .260 I sighted in I did use the Burris mount's windage adjustment to center things up and then tweaked it with the scope adjustment. I haven't done much shooting over 200 yards (except with an iron sighted "buffalo gun"!) so I haven't ever adjusted the scope for different ranges while shooting.

SingleShotLover · Posted: Fri Jul 10, 2009 5:06 am Post subject: Re: dead on at 25 yds.

I try to make sure that the cross hairs are centered within the scope (both vertically and horizontally) as close as possible to my chosen zero setting (100,200, 250 yards etc.) even if it means shimming bases ever since I read several articles that pointed out that parallax is much less severe in the center of the optical plane. Even adjustable parallax scopes are a little more forgiving if set up this way.

Dawgdad · Posted: Fri Jul 10, 2009 7:03 am Post subject: Re: dead on at 25 yds.

For 99% of the people who shoot scoped rifles, if you are setting up a scope for a point blank zero of 300 yards or less I can see centering on both planes for the optical reasons given.

If you plan to shoot at extended ranges, I would consider setting it up with the verticle closer to the bottom to allow maximum elevation.

wtf

What effect does shimming a scope mount to get a zero lower in the elevation range at 100 yards have on you projected, as calculated by Point Blank, come ups at distance? I knw we are talking .001"'s here but .001" here can be a lot 800 yards down range.

I know you have to shoot it at the distance to be sure but is there a general effect that can be predictive?

tbox61 · Posted: Tue Jul 21, 2009 2:23 pm Post subject: Re: dead on at 25 yds.

Hi guys--been away for a bit, but am now back...I have had better luck with my rifles since I started optically centering the reticle BEFORE I have anyone bore sight it.

Optically centering is easy--if you have variable scope, turn it to it's lowest setting, then put the objective end against a mirror and look throught the eyepiece. You will usually see two reticles, the actual one, and the reflected one. Just adjust the windage and elevation to where you only see one reticle and you are done.

I have been way closer on paper after doing this, then manually bore sighting.

I have found the PB program to be invaluable to me--in fact it is on my laptop and goes to the range with me when I chrono my loads.

I put a piece tape on my stock referencing the drops over the ranges I expect to shoot--been close enough for minute of coyote or deer for me!

Regards,
Tim

Gil Martin · Posted: Tue Jul 21, 2009 3:32 pm Post subject: Re: dead on at 25 yds.

Starting at 25 yards is just fine. Then I try it at 50 yards and finally at 100 yards. This is the fastest and probably the best way to get sighted in. I have seen guys shot a box of shells at 100 yard targets and never hit a 3' X 5' backstop.

Boresighting is an approximation that needs to be verified at the range. A lot of rifles have been drilled and tapped off center so checking at the range is essential. When I worked at a gun shop part time, I cannot tell you how many folks showed up the night before deer season to buy a rifle and scope and asked us to bore sight it. We did and told them to check it out at the range. All the best...
Gil

sniper · Posted: Thu Jul 30, 2009 10:14 pm Post subject: Re: dead on at 25 yds.

The point of the whole exercise is to get the rifle on the paper at 25 yards, which will result in a hit on the target at 100 yards, shooting close enough to easily refine the zero.

I mean, who can miss a foot square target at 25 yds, right? Embarassed

Uh-huh!

The next step, is at 100 yards, where you sight in ~2 1/2 - 3 in. high so theoretically, the bullet doesn't travel more than +- 3 inches above or below the point of aim out to what is called "point blank range", which is amazingly similar for a large variety of cartridges...iirc, less than 20 yards.

Again, very theoretically, this should keep your bullets within a 6 in circle on your target, resulting in a fatal hit with a center of body hold from the muzzle to in excess of 250 yards. Try it, you may like it!

That's what all the hoo ha surrounding the "rangefinding" scope reticles is all about. Hit easier.

I find them less than useful.

Actually, on my Burris Fullfield II, they are too small to be much assistance. But, that's just me.

Know your gun and load, sight in 2.5-3 in. high at 100 yards, and FEAR NOT! Ka POW! gottim! Very Happy

kentucky hareraiser · Posted: Fri Jul 31, 2009 9:31 am Post subject: Re: dead on at 25 yds.

foot high at 25 yards ??? what did you do the joe Smile