CDS tips.

[MT257]

I am getting ready to send in my order for a CDS dial. I have a ten shot average velocity calculated. What’s the best way to measure sight height? How close does the elevation and temp need to be? I’ll be using a nosler accubond, is the BC listed by Nosler good enough? Any other tips are appreciated

 

[aaronoto]

Sight height - I usually use a pair of calipers and measure from center of the bolt to the center of the scope tube. A ruler or tape measure works too...

Elevation matters more then temperature. I'd get a range of low elevation and high elevation in your hunting areas and pick the middle. Hopefully your range isn't sea level to 6,000 ft....

Factory BC is good enough.

 

[Banded_spooney]

Sight height - I usually use a pair of calipers and measure from center of the bolt to the center of the scope tube. A ruler or tape measure works too...

Elevation matters more then temperature. I'd get a range of low elevation and high elevation in your hunting areas and pick the middle. Hopefully your range isn't sea level to 6,000 ft....

Factory BC is good enough.

My range is 100 feet at the house to 10k in Colorado so that's fun on the CDS. -- I site in at the cabin at Mt. Shasta, puts me about 4,800. Set the CDS for 5k which covers me in Wyoming or the middle range Sierras. But hunting orchard or river bucks here or 3rd season Colorado gets a bit tricky.

 

[SomeJackassOnAForum]

The best way to measure sight height is to pull the bolt back, and measure from the firing pin up to the bottom of the tube, then add half the diameter of the tube:

1" = 1/2"
30mm = 0.6"
34mm = 0.7"

So if you measure 1.2" to the bottom of the tube, and you have a 30mm scope tube, you'd be at 1.9" Sight Height.

I'd make the elevation and temperature close to where you typically intend to use the turret, factory BC is a good place to start if you're not going to go out and shoot the rifle and then true the BC based on field results.

 

[30338]

Use JBM ballistics and simply print out drops for the hunt conditions and tape to stock. Its quite fast and works well.

 

[idig4au]

^^^^ this

 

[BigNate]

Buy an extra high altitude cap.

 

[sndmn11]

The best thing you can do is to get a generic MOA turret with a zero stop. They may come with them now, but used to not.

 

[MT257]

The best thing you can do is to get a generic MOA turret with a zero stop. They may come with them now, but used to not.

That’s what’s on it. In all honesty I’d be fine with that and field verifying my drop. I figured they give ya free custom cds so I’m curious to just see how close they are.

 

[sndmn11]

That’s what’s on it. In all honesty I’d be fine with that and field verifying my drop. I figured they give ya free custom cds so I’m curious to just see how close they are.

Does it have the little tab on the inside to act as a zero stop?

 

[MT257]

Does it have the little tab on the inside to act as a zero stop?

Yes. Sight in let’s say zero at 100 then loosen two screws set it to zero. It locks back in once returned to that zero setting.

 

[josef]

Buy an extra high altitude cap.

This. If youre going to use a CDS or any companies ballistic comp dials you can only really expect good performance in 2-3K bands of elevation. The good news is you can buy multiples and swap out as needed.

 

[JGRaider]

These are easy, inexpensive, and durable. Instead of buying extra turrets I've used these for years with great results.

Custom Turret Systems | Affordable Custom Turret Labels

 

[Wrench]

Half the action dia, Half of scope tube dia....plus the distance between the two.

Custom dials will make you feel neat, but make you miss more.

 

[TraskI]

I think the best way to get an accurate CDS dial is to shoot at multiple long ranges to see what your rifle needs for MOA of drop. Lets say 100, 300, 500, 600, 800 yards or however far you think you will shoot the rifle. Then mess with the ballistic software to match what you verified. The more distances you have proofed the better you will get. Often you'll need to mess with the FPS, BC, and scope height to get the software to match what your rifle is really doing. If you just plug the manufacturers FPS (or even verified fps), BC's, and scope height then use a calculator I doubt you will be anywhere near target past 300 yards, unless you get lucky. Seams to me every calculator and rifle throws bullets a little bit different.

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[JGRaider]

How about using a chrono? It's mandatory IMO.

 

[MT257]

How about using a chrono? It's mandatory IMO.

Got that part covered.