Range Report 338 Lapua ballistic charts

[81mike]

Since I am incompetent with the site's search engine, would one of you pro's direct me to a quality ballistics chart for the 338 Lapua 300gr. SMK? I know its here somewhere, I just can't seem to find it.

Thanks for the help

 

[Ouch!!]

Re: 338 Lapua ballistic charts

http://www.jbmballistics.com/cgi-bin/jbmtraj_drift-5.1.cgi

 

[81mike]

Re: 338 Lapua ballistic charts

Thank you...I'll just stick that link to the favorites bar and carry on. Appreciate it.

 

[jbmillard]

Re: 338 Lapua ballistic charts

Please keep in mind that when you use the basic trajectory program for drop charts, they're really only good at the zero temperature unless you do what this article is talking about:

Elevation

This is the reason that my trajectory card programs were written.

Brad

 

[Lindy]

Re: 338 Lapua ballistic charts

And excellent programs they are, too - accurate and easy to use.

If you zero at shorter ranges, the change from the zero conditions to the shooting conditions won't have much effect.

<span style="font-style: italic">However</span>, the change in muzzle velocity with temperature at longer distances <span style="text-decoration: underline">will</span>, as you know, have a significant effect. And many shooters neglect to compensate for that change. Actually, not many shooters even have a good idea what that change is for their load.

 

[DaveV]

Re: 338 Lapua ballistic charts

Lindy, maybe a bone head question, but, if using a DA chart, won't the temperature changes be factored in? If not, how do you compensate for the changes aside from trial and error and DOPE tweeking? Do you load different loads for different expected temps (with accompanying DA charts)?

 

[Lindy]

Re: 338 Lapua ballistic charts

A DA chart compensates for the changes in atmospheric drag as a result of temperature changes. I find it easier to compensate manually for changes in muzzle velocity as a result of temperature change - see my recommendation for that in Making Ballistic Cards Using Density Altitude.

However, note that Brad's JBM ballistic card program <span style="font-weight: bold">will</span> include a change of muzzle velocity with temperature in its calculations, if you know what the change for your load is, and you tell the program to use it.

Doing that, for me, results in a lot more output from the program than I want, so I don't do that. But my way is not the only way.

 

[DaveV]

Re: 338 Lapua ballistic charts

I read your article quite a while back and should have re-read it before asking. You covered it very well. Thanks.