Ordering a CDS for 308

[Duckslayer89]

Trying to figure out what my muzzle velocity is on a 22 inch barrel with 308 nosler 165 grain accubonds. I can't find on noslers website what inch barrel they get their ballistics from. I have a feeling it's 24 and mine is only 22. Kimber mountain ascent. Any help appreciated

[Blacklab]

To get the full benefits of a CDS, you'll need to chronograph your loads.

[Duckslayer89]

Id like to try to get away without having to purchase one but that would be the best idea. Anyone else with a Mountain Ascent in 308 that shoots 165 factory accubonds ?

[Taco280AI]

Don't get the dial without knowing what your rifle is shooting at.

[Duckslayer89]

Don't get the dial without knowing what your rifle is shooting at.

So you wouldn't go by the Nosler ballistics for the accubonds from factory

[Taco280AI]

I've chrono'd Nosler ammo from my 280AI and would say no. Of three different factory loads of theirs one was about 24fps off. Not a big deal. Another was over 100fps slower than advertised and the third was well over 200fps slower. You just never know until you shoot it through your rifle and note the temp conditions when doing so.

[Duckslayer89]

I've chrono'd Nosler ammo from my 280AI and would say no. Of three different factory loads of theirs one was about 24fps off. Not a big deal. Another was over 100fps slower than advertised and the third was well over 200fps slower. You just never know until you shoot it through your rifle and note the temp conditions when doing so.

What kind of chronograph are you using? Thanks for the heads up sounds like it could be a big difference

[hogslayer]

I have 2 chronographs if you want to come shoot through one or borrow it for the day.  I wouldn't chance it with getting a CDS.  All the factory ammo i have shot was less than advertised on the box by quite a bit with the same barrel length.  Other way to do it would be take the fps marked on the box and enter your info into a ballistic app.  then go out and shoot at 300 yards and 600 yards and measure your drop.  Then you can adjust the fps in the app until it matches the real world drop. 

[b23]

The majority of factory centerfire rifle ammo, regardless of who's it was, that I've chrono'd has been substantially slower (100-200fps) than was advertised on the box with Nosler being one of the worst.  Doesn't mean it shoots bad but never go off of what the box says for velocity.  Rimfire ammo, surprisingly, is typically pretty close to advertised.

[Magnum_Willys]

Looking at their loading data kinda makes you suspect their 2800 fps for factory loads might be a little high.....

[Bob33]

To take advantage of a CDS dial you need accurate inputs of the variables, including velocity. The best way is to shoot several rounds over a chronograph.  You can't trust factory published data to be accurate enough because every gun and barrel may produce different results.

If you don't have access to a chronograph, you can get a pretty accurate estimate of the velocity by reverse computing it with ballistics software. Shoot the load at 100 yards, measure the vertical distance from point of aim, and then repeat at progressively longer distances. If you can shoot at 400 yards or longer, you should be able to compute the velocity fairly close by playing around with the velocity in the software until the drop results match your actual results.

A chronograph is really the best way. Also remember that air pressure as estimated by altitude, and ambient temperature affect bullet drop and that data will need to be provided for the dial. If you can do your velocity testing in conditions close to those where you hunt, it will help.

[Duckslayer89]

Ended up buying a chronograph today and a bunch of other stuff. Wheeler FAT WRENCH, P3 gun vise, competition electrics  Pro-chronograph, wheeler professional level system, and new talley lightweight rings just because. Going to do everything right and get that CDS dialed in perfect. Can't wait. Thanks for everyone who offered to let me borrow everything I just figured I should finally own my own

[Magnum_Willys]

    I dialed a one-shot elk at 460 yards this year and buddy did the same at 660 yards on a 330 class bull.  Both leupold CDS.   System works ! 

[Taco280AI]

I didn't do the custom dial but do have the standard MOA dial and love it. I might hunt anywhere from 8500 feet to 12,500 so have multiple charts to look at if needed

[wsmnut]

Ended up buying a chronograph today and a bunch of other stuff. Wheeler FAT WRENCH, P3 gun vise, competition electrics  Pro-chronograph, wheeler professional level system, and new talley lightweight rings just because. Going to do everything right and get that CDS dialed in perfect. Can't wait. Thanks for everyone who offered to let me borrow everything I just figured I should finally own my own

You'll be really glad you did that.  Those dials are amazing.  I've got two, and just put one on my wife's rifle.  Headed out this morning for testing!
I have one on a 300 WSI that put a rag horn bull in the freezer at 452 yards!  It's great fun to get out and start testing them at longer ranges.  Enjoy!