Burris Pos-Align Inserts How many Moa do I need for 1000yrds


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O.T. Powell
November 18, 2012, 08:45 PM
Ok guys. I used to know more about this but i think I may be a little rusty. I have a Zeiss 3-9x40 which my rifle is zeroed @ 100yrds. My scope has an adjustment range of 64in/100 yards. My sight height is about 1.7 inches. Currently, my scope has a cant of 0 moa. I think I'm approx in the middle of my elevation click adjustment range. I need about 40 moa of elevation (or 158 clicks) to shoot out to 1000 yards. How much cant can I put on my scope with these posalign rings, to still zero my scope at 50 yards, but be able to adjust it for a 1000 yard zero? Is 30moa too much, or is 20 moa perfect? I want to be able to zero at 50 yard with being at the bottom of my elevation range, and be able to zero at 1000 yards at the top of my elevation range.. Make sense? Feel like I'm having a brain fart right now.

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O.T. Powell
November 18, 2012, 08:49 PM
BTW, I am shooting 30-06 165gr with 4350 and/or 4064. I have 256 clicks of elevation @ 1/4 moa per click.

StretchNM
November 18, 2012, 08:54 PM
OT, I swear by the Burris Signature Zee rings, and I ordered a Pos-Align kit when I bought my first set. Always thinking they were just for the rifle/base/scope combo that just needed a little help, I have never had to use them. It never occurred to me that a guy might need to use them to get his scope to shoot out to 1000 yards!

Holy mackeral the math seems hard. As dumb as I am, I think I would just play with them until I got it right, admitting that that is a lot of work!

browningguy
November 18, 2012, 09:05 PM
Well I'm not going to do the math, but with 30 moa inserts (which work really well for 100 yards, I cant get my .243 Winny with an 8-32 Burris to zero at 100. So I went back to 20 moa inserts and now everything is fine.

O.T. Powell
November 18, 2012, 09:11 PM
Just seems like I have alot of spare elevation at the bottom of my adjustment range.. Guess this question would be more valid if I actually had enough magnification to see clearly at 1000 yards.. I wonder if 9x is enough to hit a target at 1000 yrds. Hmm.. Maybe I'll get another Zeiss with more magnification..

hoghunting
November 18, 2012, 09:31 PM
You can use the +/-.020 inserts on both rings for a total of 40 MOA or a combination of the .005, .010 or .020 inserts for 5 to 40 MOA.

JAV8000
November 18, 2012, 09:36 PM
20 moa should be fine, in sniper section we have 20 moa bases and leupold low rings on our XM2010 300 winmag long guns and leupold ER/T 6.5-20 scopes. They can be spun up past 1200 yards without issue.

O.T. Powell
November 18, 2012, 09:41 PM
I think I'm just going to count how many clicks I have until I hit the bottom of my adjustment range, divide by 4, and minus 5 moa so that I can zero closer than 100yrds.

O.T. Powell
November 18, 2012, 09:43 PM
Thanks for the replies all! I think I'm going to go with 20 or 25 moa then adjust my point of aim downward by the same amount of moa.

USSR
November 18, 2012, 09:54 PM
O.T. Powell,

You're using the wrong bullet and the wrong powder. I shot in 1,000 yard competition for several years with a .30-06, and my load only required 30MOA of elevation from a 100 yard zero to reach 1k.

Don

O.T. Powell
November 18, 2012, 10:05 PM
I'm still learning.. Which powder & bullet did u use? I am using 168 gr Sierra match kings.. Never actually shot out to 1000.. Not alot of opportunity for that range here in Florida.. I used to live in Michigan on 20 acres, boy did I take that for granted.

O.T. Powell
November 18, 2012, 10:08 PM
I need a chrony to get accurate muzzle velocity. My ballistics software plugged in 2800 fps for the load I am using and I think it may be faster than that. @ 2800 I am supposed to dial 39moa to reach 1000

USSR
November 19, 2012, 09:05 AM
I'm still learning.. Which powder & bullet did u use? I am using 168 gr Sierra match kings.. Never actually shot out to 1000.. Not alot of opportunity for that range here in Florida.. I used to live in Michigan on 20 acres, boy did I take that for granted.

O.T. Powell,

The 168gr SMK was designed for International Shooting (300 meters), and is not a good long range bullet. It's boattail is not the 9 degree boattail that is commonly found on long range bullets, and it tends to become unstable as the velocity drops at long range. Assuming you are using a modern bolt action rifle, here is my load:

Lapua or LC Match brass
Fed. 210M primer
190gr Sierra MatchKing bullet
60.7gr RL22 powder

If using Winchester or Norma brass, you will need to add a bit more powder. From my 26" barreled Winchester Match Rifle, I get 2900fps. Hope that helps.

Don

helotaxi
November 19, 2012, 09:41 AM
You also have to realize that the inserts are not labeled in MOA but in fractions of an inch of offset. To get that to convert to MOA directly, the scope rings have to be exactly 6 inches apart. If your scope rings are closer together than that, the offset in MOA will be greater than the offset in thousandths. If they are farther apart it will be less.

O.T. Powell
November 19, 2012, 01:53 PM
Now that is great info! Thank you all!

floorit76
December 8, 2012, 11:27 AM
I believe I'm going to give this a shot as well. I'm mounting a Vortex Viper 6.5-20x44 on my Sps varmint in 308. There are quite a few discusions of this on the web if you look around. Here's one.


http://bulletin.accurateshooter.com/2012/08/tech-tip-burris-signature-rings-calculating-actual-elevation-changes/

Burris Signature Rings with polymer inserts are an excellent product. The inserts allow you to clamp your scope securely without ring marks. Moreover, using the matched offset inserts you can “pre-load” your scope to add additional elevation. This helps keep the scope centered in its elevation range while shooting at long range. Additionally, with a -20 insert set in the front and a +20 insert set in the rear, you may be able to zero at very long ranges without using an angled scope base — and that can save money. (To move your point of impact upwards, you lower the front of the scope relative to the bore axis, while raising the rear of the scope.)



Insert Elevation Values and Ring Spacing
People are sometimes confused when they employ the Burris inserts. The inset numbers (-10, +10, -20, +20 etc.) refer to hundredths of inch shim values, rather than to MOA. And you need the correct, matched top/bottom pair of inserts to give you the marked thousandth value. Importantly, the actual amount of elevation you get with Burris inserts will depend BOTH on the insert value AND the spacing between ring centers.

Forum member Gunamonth has explained this in our Shooters’ Forum:

Burris inserts are [marked] in thousandths of an inch, not MOA. To know how many MOA you gain you also need to know the ring spacing. For example, with a -20 thou insert set in the front and a +20 thou insert set in the rear, if the ring spacing is 6″, the elevation change will be approximately +24 MOA upwards.



Here’s how we calculate that. If you have a 2 X 0.020″ “lift” over a distance of 6 inches (i.e. 0.040″ total offset at 0.5 feet) that’s equivalent to 0.080″ “lift” over 12 inches (one foot). There are 300 feet in 100 yards so we multiply 0.080″ X 300 and get 24″ for the total elevation increase at 100 yard. (Note: One inch at 100 yards isn’t exactly a MOA but it’s fairly close.)

Here’s a formula, with all units in inches:

Total Ring Offset
——————– X 3600 = Change @ 100 yards
Ring Spacing

(.020 + .020)
—————– X 3600 = 24 inches at 100 yards
6

NOTE: Using the above formula, the only time the marked insert offset will equal the actual MOA shift is when the center to center ring spacing is 3.60″. Of course, you are not required to use 3.60″ spacing, but if you have a different spacing your elevation “lift” will be more or less than the values on the inserts.

helotaxi
December 9, 2012, 11:56 AM
I did the math some time back using trig and figuring angles and got a slightly different answer.

floorit76
December 9, 2012, 12:01 PM
I didn't verify the math, just posted the link. If yo did the calculations, I assume you are useing this settup. How is it working for you? I ordered a set last night after driving an hour to find out they really didn;t stock them, even though the kid on the phone said they did.

WYOMan
December 9, 2012, 12:55 PM
You'll have to excuse me, all I have are my brothers notes for referance here. He was the 30-06 guy. His load for his long range rig was 180 SMK, 54.5 grains of IMR 4831, Rem brass, WIN LRP, Avg. Vel. 2671 with an SD of 8.94 from a 26-28 inch Shilen 1-10 twist barrel. I know this may not help, but he used a SWFA 10X42 Super Sniper, zeroed at 100, and could still dial to 1000. I punched the numbers and got 36.5 MOA. They have 150 MOA total adjustment, or 75 each way from center. I use a Burris Black Diamond on my rig with the offset inserts because I only have 50 MOA total.

floorit76
December 9, 2012, 01:07 PM
I have 65moa adjustment available in the vortex viper.

helotaxi
December 9, 2012, 01:07 PM
I have these rings on 6 different rifles but only one was for the use of the offset bushings. That particular rifle (a Remington made Marlin 308MX) had the barrel hole in the receiver bored about 1 degree off and originally shot about 60" low at 100yds. After adding a rail and the Burris Signature Zee rings with .020" offsets front and rear to correct the elevation problem, the rifle is zeroed with minimal scope adjustment required. Two of the other rifles that use the Signature rings have the "standard" type instead of Weaver style. I like them in that application because it allows for a lower mount to the rifle and allows the use of a windage adjustable base without concern for bending the scope tube, binding it or breaking the mechanism or marring the tube with ring marks. One of the rifles is a very lightweight 7mmWSM and the rings hold a fairly heavy Bushnell Elite 6500 scope without issue.

Overall, in the applications where they are available in the correct height, they are probably the best rings on the market.

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