.270 / .300 wby charts

five_point_buck

Very Active Member
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I have a excel file that has the drop characteristics for:

.270 shooting 150 gr sp
.300 wby shooting factory 180 gr sp

If your interested, you can email me and I'll forward it. To the right is a cut-out box that I attach with clear packing tape to my stock for quick confirmation out to 500 yards. these dimensions have been rounded to whole numbers to simplify the process.

Its come in handy over the years, so i figured I'd pass it along.


270_300.jpg


five_point_buck
C.B.C.S.
 
Too many variables IMO to use a standard "chart". Does your rifle have a 22" or 26" barrel? That affects velocity. Even barrels can change velocity vs other barrels of the same length from the same MFG. What did your velocity measure over a cronograph? What bullet are you shooting? Every bullet has a different BC. What target distance is your zero? 200? 300? 324?

IMO get your rifle cronographed... or if that isnt an option use the Ammo MFGs velocity numbers then subtract 100fps if you have a 26" barrel or 200fps if its shorter. That will be kindof rough but its a starting point (mfg velocity's are like car MPG estimates... they are all fudged on the high side). Next find out the BC of the bullet your ammo MFG is using. You can usually find it off their website or the bullet mfg if its outsourced (common in premium ammo).

THEN goto www.HuntingNut.com and either download the PC version of PointBlank or use the online version (PC version is more robust) and calculate a much more accurate trajectory based on your own variables and preferences.


-DallanC
 
Bonefreak, Its on its way..... hope it helps....

DallanC....

First off, I never claimed this to be the "bible" or perfect for every shooter, nor did I think folks would head out to the local long range competition and take the gold medal. This is dumbed down for practical hunting applications. If it doesn't suit you, move onto the next post.

I have taken into account all the things you have said. The "zero" is clearly listed on the charts, the bullets are weatherby factory 180 sp (.300), and Hornady 150 SP for the .270 win.
Weatherby barrell is 26" #2 contour with 1-10 rifling. The winchester is a model 70 featherweight with a 22" barrel.

Once again, this isn't for swat teams or long distance competitions. This is a chart for quick reference in the field, trying to place a bullet in the heart lung area of a big game animal. I have rounded the numbers to whole numbers, because at ranges less than 400, there is no real difference between 4.6 inches and 5 inches. Aiming at deer and elk with vitals the size of a paper plate (or bigger), this is more than enough information in typical situations. Its up to the operator to use his/her best judgement, and add insight for wind drift, weather conditions, and elevation. Once again, this "quick reference" tool would be very helpful for most hunters in many situations.

For the person that's never done the math, this is one step closer to ethical kill shots. I could have made it more custom, or more precise, but why. It was offered for anyone who might be shooting two relatively popular set-ups. All this data was crunched from the manufacturers data, the point blank software, the ballistic calculator at http://www.biggameinfo.com/BalCalc.aspx, and tripple checked with a local swat teams sniper ballistic calculation software which is proprietary. (Yes, my hunting partner is a sniper on a real sniper team). Once the numbers were crunched, the loads and numbers were cross checked at the range to confirm they were close.

Yes, each shooter should take some steps to know ones load and performance. Lets be honest, it rarely happens. If this helps one guy place a better shot that results in a quicker, cleaner kill, then I have helped. Maybe someone sees this and takes the time to learn more about their own set-up. I see it as win win either way.

five_point_buck
C.B.C.S.
 

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