How much wind?

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40-65rl
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Location: cheyenne, wy

How much wind?

Post by 40-65rl »

So I am new to the target matches and have a couple of questions for the seasoned target shooters on the forum.

Is the black on the 600 yard target 36 inches across? Is that three minutes?

Next, what is the diameter of the black on the 800, 900 and 1000 yard targets? How many minutes each?

If I launch a 535 grain bullet at 1400 fps from my 45-70 at the 1000 yard target with a 20 mph straight left to right wind, how many minutes of adjustment would I need from my no wind setting to hit the "X"? Considering the bullet drift to the right and the bullet drop.

Please be kind in your replies, thanks

Dick
Clarence
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Re: How much wind?

Post by Clarence »

Dick,

The 60 yd target is ~36", which is ~6 MOS, so 3 MOA from center to edge.

The best way to answer your other question is to play with a ballistic calculator, such as JBM. Enter the required information, and use 0.400 as the BC at standard conditions for starters. Adjust the BC as required to reflect your actual sight settings (usually, somewhere between 0.400 and 0.450 seems to work for me).

You can set JBM to give you the drop at any range from a zero range, such as 100 or 200 yds., and the windage at any range you select. You can have the range card print in either inches or MOA (or both), and for your choice of range increments and maximum range.
Clarence
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Re: How much wind?

Post by Clarence »

Dick,

One example: Sorry the columns don't line up--they line up perfectly when you print from JBM. This is the simplified trajectory model.

Clarence


Trajectory (Simplified)
Input Data
Ballistic Coefficient: 0.400 G1 Caliber: 0.458 in
Bullet Weight: 535.0 gr
Muzzle Velocity: 1400.0 ft/s
Sight Height: 2.00 in Line Of Sight Angle: 0.0 deg
Cant Angle: 0.0 deg
Wind Speed: 20.0 mph Target Speed: 10.0 mph
Temperature: 59.0 °F Pressure: 29.92 in Hg
Humidity: 0 % Altitude: 3000.0 ft
Std. Atmosphere at Altitude: No Pressure is Corrected: Yes
Zero at Max. Point Blank Range: No Target Relative Drops: No
Column 1 Units: 1.00 MOA Column 2 Units: 1.00 MOA
Round Output to Whole Numbers: No
Output Data
Elevation: 10.909 MOA Windage: 0.000 MOA
Atmospheric Density: 0.06854 lb/ft³ Speed of Sound: 1116.4 ft/s
Maximum PBR: 180 yd Maximum PBR Zero: 152 yd
Range of Maximum Height: 84 yd Energy at Maximum PBR: 1704.7 ft•lbs
Sectional Density: 0.364 lb/in²
Calculated Table
Range Drop Drop Windage Windage Velocity Mach Energy Time Lead Lead
(yd) (MOA) (MOA) (MOA) (MOA) (ft/s) (none) (ft•lbs) (s) (MOA) (MOA)
0 *** *** *** *** 1400.0 1.254 2328.0 0.000 *** ***
100 -0.0 -0.0 3.3 3.3 1280.4 1.147 1947.1 0.224 37.7 37.7
200 -9.2 -9.2 6.7 6.7 1179.4 1.056 1652.1 0.469 39.4 39.4
300 -20.2 -20.2 10.0 10.0 1099.0 0.984 1434.4 0.733 41.0 41.0
400 -32.6 -32.6 13.2 13.2 1036.8 0.929 1276.7 1.014 42.6 42.6
500 -46.2 -46.2 16.1 16.1 987.5 0.884 1158.1 1.311 44.1 44.1
600 -60.9 -60.9 18.8 18.8 946.5 0.848 1064.0 1.622 45.4 45.4
700 -76.7 -76.7 21.4 21.4 911.0 0.816 985.8 1.945 46.7 46.7
800 -93.6 -93.6 23.8 23.8 879.5 0.788 918.7 2.281 47.9 47.9
900 -111.5 -111.5 26.2 26.2 850.9 0.762 860.0 2.629 49.1 49.1
1000 -130.5 -130.5 28.4 28.4 824.6 0.739 807.7 2.988 50.2 50.2
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bpcr shooter
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Re: How much wind?

Post by bpcr shooter »

how you getting 1400fps with a 535gr bullet in a 45-70?
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desert deuce
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Re: How much wind?

Post by desert deuce »

What Clarence posted looks like it will get you in the ball park and fairly close. A good start and good advice.

However, if you find that shooting target, especially long range, is akin to flying without instruments or riding a bicycle without handlebars don't be overly surprised. Most suspect that the inability to determine the intervening conditions lack anywhere from little precision in determining conditions to a total mystery. (Usually referred to as becoming lost in the conditions.) Fear not, you will not be alone.

Noticed at a match I fired recently the 1,000 yard elevation varied 7 minutes between relays. Don't fret those kinds of things. Just adjust the sights and make note of the variance and if you are prone to worry then worry about that after the match.... :wink:

In doping conditions perception is the key. It seems a proficiency level above 80% of shots in the x-10 ring indicates above average under moderate or average conditions at most ranges. Conditions directly affect proficiency. With "Mary Poppins Wind and Mirage" scores will be much, much higher to exceed 90% even. Condition change on the same day at the same range, same shooters may dip to 60% or less.

I suspect the key is become one with your rifle, don't fire any bad shots and listen to what you see in the spotting scope and to where the bullet strikes the target.
Sometimes you get the chicken, and sometimes you get the feathers!
bruce m
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Re: How much wind?

Post by bruce m »

how do you get 1400 fps out of that wt bullet in a 45/70?
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powderburnt
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Re: How much wind?

Post by powderburnt »

I use 1 minute per mph of 90 degree wind out to 600 yards to get on paper from mechanical zero in my 45-90 and 40-65. Haven't shot a 1000 yet but I''m working toward it.

HG
40-65rl
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Re: How much wind?

Post by 40-65rl »

Clearance and DD, thank you very much. I went to the ballistics calculator and put in my true velocity, about 1275, miss hit the keys and didn't see it until after it was posted and could not correct it. Figured I just let it fly and you all were very polite about it. Surprisingly, got almost the same drift as with the 1400 fps. A change in altitude, I shoot at over 5000 feet, raised the temp to 80 degrees, and changed the humidity to reflect that we have very little and it made some difference also. Still about 25 minutes. Thanks for the advice about the calculator. Will be using it in the future.

Thanks to all who replied. This is a great game, been at it for over 20 years and have met and shot with some of the best folks on the planet.

This target game seems best shot with iron sights, not just for tradition but the scope just doesn't seem to hold as well as the irons. Now that I have my "new" eyes, cataract surgery, I can see again and the irons just seem like a better way to go. What do you think?
Clarence
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Re: How much wind?

Post by Clarence »

Dick,

I took a guess at your elevation and temperatures. Glad to see you played with the calculators it will be interesting to see how your observations during matches compare. DD's caveats definitely apply.

Clarence
40-65rl
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Re: How much wind?

Post by 40-65rl »

I will be at the BPTRA creedmoor national championship at Byers, Colorado on the 25-27. See how it goes
Thanks again
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Don McDowell
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Re: How much wind?

Post by Don McDowell »

Dick get down to Byers on Thursday for practice day. You’ll get mosT of your questions answered when you can actually see what the target says.
AKA Donny Ray Rockslinger :?
40-65rl
Posts: 262
Joined: Thu Nov 20, 2014 10:44 am
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Re: How much wind?

Post by 40-65rl »

Don, will be there Wednesday am. Should be interesting.
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