Need help finding a load for my rifle

[maninthemaze]

Just an update. My scope is currently at Vortex being repaired. I'll post some more pictures once I get the scope back and start shooting it again.

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[maninthemaze]

I guess I'm happy with the loads for my rifle. I settled on the 79.8 grains of N570 and the 195 Berger. I got my scope back yesterday, mounted it last night and went and shot today. I know that I'm not the best shot, and shooting a lightweight (for me) rifle is more difficult. I definitely need to practice more. Anyways. I bore sighted the rifle. First shot was 5 inches high at 100 yards I dialed down 3 MOA and stepped back to 200 yards. Second and third shots were a little right, but the elevation was good. Stepped back and dialed for 400 yards and a little left, fired three rounds (the wind had started gusting 5-10 mph. Windage was right, elevation was still an inch high so I dialed down 1/2 MOA and the last three shots were decent with a 1 3/4 spread. For those last three shot I also placed the magneto speed on the rifle just to check velocity. They were 3087, 3072 and 3083 for a SD of 7 and an ES of 15 with an average of 3080. I'll take that every day of the week and twice on sunday. Anyways, thanks to all who replied and helped along the way.

And the picture is sideways??

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[maninthemaze]

And with my last two rounds I got cocky, stepped back to 700 yards and missed the grand finale of my milk jug full of water. The wind always shows me how little I know.

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[danmayland]

And with my last two rounds I got cocky, stepped back to 700 yards and missed the grand finale of my milk jug full of water. The wind always shows me how little I know.

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Good shooting!!

That's the beauty of the game!! Here's a hint on how to read wind at your target in those long shots.
- zoom all the way in on your target and run the parallax until everything is blurry. You will be able to see the heat waves dancing in the direction the wind is blowing. Then zoom out slowly and watch if it changes making sure to keep your parallax out of focus.

One thing this pic doesn't explain is the height of the heat wave is directly correlated to the speed of the wind. Larger, higher heat waves equate to slow wind speeds and smaller, quicker heat waves equate to faster wind speeds. You will be looking at horizontal heat waves of course so it's important to look at the vegetation.
Tree branches usually start to move between 8-12 mph. Tall grass will flutter in 3-5mph. It will lay flat in 12-15mph. Sagebrush doesn't move much but if it's moving the wind is probably 15+mph

Also don't forget that heat waves can and do cause target displacement as seen below.

Head spinning yet?!?!
It's not as complicated as it seems. I don't worry about Target displacement until I get past 1,000 yards and then I usually over compensate on wind speed for the correction.

Lastly, the most important thing to remember is this:

Your bullet will be affected the most by the wind in which it spends the most time.

Think of it like this:

Your shooting across a canyon. Your on the top of one side and your target is on the top of the other side. This distance is 800 yards.

You have a 3-5 mph wind blowing up hill in your face at your location.

You have a 6-8 mph wind blowing from right to left down the canyon.

You have a 3-5 mph wing blowing up hill towards the target at the target location.

What do you do? This is a very real and practical situation.

Where does the bullet spend the majority of its flight?

Crossing the canyon!

I know that I must dial 15.8 moa for 800 yards

I know that the bullet will be affected the most by the 6-8 mph right to left wind.

I know I must dial or hold 2.3 moa for 8mph wind

I know that spin drift is 4-6" right (because I have a right twist barrel) or .5 moa at 800 yards

So here's what I'm going to do.

I'm going to dial 15 moa because I know my bullet is going to rise from the wind at both my shooting location and target location. (Subtracting .8moa from my dope)

I'm going to either dial or hold 1.7 moa to the right (into wind) to compensate for spin drift and wind.

I'm going to execute the shot and hit my target!!

It's very likely with long range shots that your going to have opposing winds. It's super important to read your wind at all points of the bullets path. The peak of the bullets path and the end of the bullets path will be most affected by wind. I rarely even consider the wind at my shooting location unless I believe it's the same at my target.

Lastly, wind flows like water over the terrain. It will follow natural paths of resistance. Cold air sinks and hot air rises right! So will your bullet!
Cheers!!

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[maninthemaze]

The above post is exactly why I love Rokslide. People taking time out of their busy schedule to help someone they'll probably never meet in person. I would really like to shake your hand one day to say "thank you."

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[Jordan Smith]

Good shooting!!

That's the beauty of the game!! Here's a hint on how to read wind at your target in those long shots.
- zoom all the way in on your target and run the parallax until everything is blurry. You will be able to see the heat waves dancing in the direction the wind is blowing. Then zoom out slowly and watch if it changes making sure to keep your parallax out of focus.

One thing this pic doesn't explain is the height of the heat wave is directly correlated to the speed of the wind. Larger, higher heat waves equate to slow wind speeds and smaller, quicker heat waves equate to faster wind speeds. You will be looking at horizontal heat waves of course so it's important to look at the vegetation.
Tree branches usually start to move between 8-12 mph. Tall grass will flutter in 3-5mph. It will lay flat in 12-15mph. Sagebrush doesn't move much but if it's moving the wind is probably 15+mph

Also don't forget that heat waves can and do cause target displacement as seen below.

Head spinning yet?!?!
It's not as complicated as it seems. I don't worry about Target displacement until I get past 1,000 yards and then I usually over compensate on wind speed for the correction.

Lastly, the most important thing to remember is this:

Your bullet will be affected the most by the wind in which it spends the most time.

Think of it like this:

Your shooting across a canyon. Your on the top of one side and your target is on the top of the other side. This distance is 800 yards.

You have a 3-5 mph wind blowing up hill in your face at your location.

You have a 6-8 mph wind blowing from right to left down the canyon.

You have a 3-5 mph wing blowing up hill towards the target at the target location.

What do you do? This is a very real and practical situation.

Where does the bullet spend the majority of its flight?

Crossing the canyon!

I know that I must dial 15.8 moa for 800 yards

I know that the bullet will be affected the most by the 6-8 mph right to left wind.

I know I must dial or hold 2.3 moa for 8mph wind

I know that spin drift is 4-6" right (because I have a right twist barrel) or .5 moa at 800 yards

So here's what I'm going to do.

I'm going to dial 15 moa because I know my bullet is going to rise from the wind at both my shooting location and target location. (Subtracting .8moa from my dope)

I'm going to either dial or hold 1.7 moa to the right (into wind) to compensate for spin drift and wind.

I'm going to execute the shot and hit my target!!

It's very likely with long range shots that your going to have opposing winds. It's super important to read your wind at all points of the bullets path. The peak of the bullets path and the end of the bullets path will be most affected by wind. I rarely even consider the wind at my shooting location unless I believe it's the same at my target.

Lastly, wind flows like water over the terrain. It will follow natural paths of resistance. Cold air sinks and hot air rises right! So will your bullet!
Cheers!!

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Great post. I have one thing to add- the wind that affects the bullet the most, is the wind which is closest to the shooter and which deflects the bullet earliest in its trajectory.

To follow with your example, suppose we have a narrow band of wind, say through a drainage directly in front of the shooting position, that is 292 yards long (spanning from 0-292 yards), and is 10 mph full value. We also have a larger band of wind flowing through a canyon downrange, which is also a 10 mph full value wind, but is 428 yards long (wind is between 572 and 1000 yards down range). The bullet spends considerably more time in the band of wind downrange in the canyon, but is deflected off course more by the narrower band of wind at the shooting position. At 1000 yards, wind drift is greater due to the wind at the muzzle than the wind at the target.

To help readers visualize this principle, imagine going on a road trip. If you take the wrong exit somewhere along the route, which would lead to you being more off course after driving 1000 miles, taking a wrong exit early in the trip, or right before you reach the destination? Obviously taking the wrong exit early in the trip will lead to you being farthest from the intended destination after driving 1000 total miles. The same applies to the trajectory of a bullet.

 

[danmayland]

Great post. I have one thing to add- the wind that affects the bullet the most, is the wind which is closest to the shooter and which deflects the bullet earliest in its trajectory.

To follow with your example, suppose we have a narrow band of wind, say through a drainage directly in front of the shooting position, that is 292 yards long (spanning from 0-292 yards), and is 10 mph full value. We also have a larger band of wind flowing through a canyon downrange, which is also a 10 mph full value wind, but is 428 yards long (wind is between 572 and 1000 yards down range). The bullet spends considerably more time in the band of wind downrange in the canyon, but is deflected off course more by the narrower band of wind at the shooting position. At 1000 yards, wind drift is greater due to the wind at the muzzle than the wind at the target.

To help readers visualize this principle, imagine going on a road trip. If you take the wrong exit somewhere along the route, which would lead to you being more off course after driving 1000 miles, taking a wrong exit early in the trip, or right before you reach the destination? Obviously taking the wrong exit early in the trip will lead to you being farthest from the intended destination after driving 1000 total miles. The same applies to the trajectory of a bullet.

Not to be argumentative but this is the exact opposite of what I've experienced in long range shooting. This has only ever been the case in my experience if the wind is 20+mph at the shooting location and some thing completely different at the target location.

You example is logical but your forgetting that the bullet starts slowing down the second it leaves the barrel. It will be more affected by wind the farther away from the barrel and the slower it travels.

I certainly could be wrong but as stated in my experience the bullet is least affected by the wind at the shooters location. That is of course unless the wind is constant throughout the bullet path from shooter to target. That rarely happens is long range shooting!

I'd love for other experienced long range shooters to chime in with their experience!!


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[Jordan Smith]

Not to be argumentative but this is the exact opposite of what I've experienced in long range shooting. This has only ever been the case in my experience if the wind is 20+mph at the shooting location and some thing completely different at the target location.

You example is logical but your forgetting that the bullet starts slowing down the second it leaves the barrel. It will be more affected by wind the farther away from the barrel and the slower it travels.

I certainly could be wrong but as stated in my experience the bullet is least affected by the wind at the shooters location. That is of course unless the wind is constant throughout the bullet path from shooter to target. That rarely happens is long range shooting!

I'd love for other experienced long range shooters to chime in with their experience!!


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No problem, I appreciate a good discussion on this stuff.

I'm not forgetting about the velocity decreasing from the muzzle on out. Despite the fact that the bullet is slowing down, and consequently spends more time flying through the wind further down range, the trajectory is impacted more by an equal wind closer to the shot location. This is consistent with my experience, and I have verified it using robust ballistic calculators, entering in various wind profiles along the course of fire. Try it for yourself and you'll see what I mean.

Perhaps the reason that this principle seems to run contrary to your experience, is that it can be VERY difficult to get an actual grasp of what the wind is doing all along the path down range, from your shooting position. Too bad wind is transparent, or it'd be a lot easier to see What seems like a wind current that is exclusively close to the target, may actually be a wind profile that begins not far from the shooting position, and continues all the way to the target. Just a thought.

 

[danmayland]

Very true!


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[maninthemaze]

Definitely like this load in my rifle. I was shooting today to triple check my 200 yard zero before my elk hunt next month. I also need to practice more shots in the wind. After my target practice at 200 and 400 yards I backed up to 650 yards. The wind was blowing 3 to 5 mph left to right. I dialed up 9.5 MOA and 1/4 MOA left. I'm shooting a bottle of ERA detergent. It's a little larger than a gallon of water. Either way, first shot hit dead center on vertical but caught the left edge of the bottle, draining half the water out. Second shot hit dead center vertical and horizontal. Unfortunately, this was the top of the water line, so I thought it was a miss. Third shot hit about and inch from the bottom and about an inch left, exploding the bottle.

Definitely gonna keep this load. Thanks again for all the help, tips and pointers along the way. Just curious though, at what point does spin drift start to calculate into the equation? 1000 yards?

Just my 2 cents and worth the price charged.

 

[Jordan Smith]

Spin drift enters the equation right from the muzzle, but doesn't begin to be a significant factor in windage corrections until beyond about 500-700+ yards.

 

[danmayland]

^ what he said! Wind will affect it much more. Just for an idea. My 7LRM spin drift is 4.2" @ 800 yards. A 4 mph wind will push it 9.7" with a 90 deg wind. Now the fun part is calculating the spin drift and the wind. If wind is from left to right then your going to add the two for a correction of 13.9" of drift. If wind is blowing right to left then you subtract for a correction of 5.5". Make sense?


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[Jakeleg]

Glad you got it all worked out,very imformative thread.Sounds just like me a few years back on a custom 7-300 I had gave me a time. Good luck and I'm a fan of N570 here to.

 

[Rthur]

I agree with everything in this post except the spin drift accounting.
Inside 1500 it contributes so little that in order to see its effect you would have to be inside 1mph wind call on all winds present.

R

 

[HellsCanyon]

I agree with everything in this post except the spin drift accounting.
Inside 1500 it contributes so little that in order to see its effect you would have to be inside 1mph wind call on all winds present.

R

Not true at all.... especially in fast twist barrels.
With spin drift accounted for at 1000 yards (10 mph wind).57" of wind drift

With spin drift disabled: 51.1" of wind drift.

Also worth mentioning is spin drift changes your wind calls from left to right and right to left depending on if you have a right hand or left hand twist barrel. It'll either combine with the wind to exaggerate the drift or it'll combat the wind and make it less of an effect. Interesting but the take away point is a 10mph wind from 90* is not the same as a 10mph wind from 270*.

Mike


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[danmayland]

I agree with everything in this post except the spin drift accounting.
Inside 1500 it contributes so little that in order to see its effect you would have to be inside 1mph wind call on all winds present.

R

This is not correct. Refer to my post above regarding actual spin drift calculations. Mike's post above is also correct. Spin drift does account for a reasonably amount of poi shift. It's as much as making a gut shot instead of a double lung shot or even a miss.


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[maninthemaze]

Do you guys think that the spin drift accounts for any vertical movement of the bullet or is it all horizontal? If you were zeroing a new rifle to be used in hunting situations, would you zero the scope to be slightly left of center at say 500 yards. That way spin drift could move the bullet more towards the center of target.

Or would you guys, just center it where it's on center, and then calculate for spin drift?

Just my 2 cents and worth the price charged.

 

[danmayland]

Do you guys think that the spin drift accounts for any vertical movement of the bullet or is it all horizontal? If you were zeroing a new rifle to be used in hunting situations, would you zero the scope to be slightly left of center at say 500 yards. That way spin drift could move the bullet more towards the center of target.

Or would you guys, just center it where it's on center, and then calculate for spin drift?

Just my 2 cents and worth the price charged.

Either is fine. A friend of mine and very skilled long range marksman actually mounts his rifle scope so that it's slightly canted accounting for spin drift. That way he just makes normal yardage and wind adjustments for his shots. I think that system is slightly more reliable although sighting in your Zero to the left (for a right twist barrel) might be a good option. I just usually account for it during the shot and usually hold left. It's something I practice enough that it's second nature.


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[HellsCanyon]

Either is fine. A friend of mine and very skilled long range marksman actually mounts his rifle scope so that it's slightly canted accounting for spin drift. That way he just makes normal yardage and wind adjustments for his shots. I think that system is slightly more reliable although sighting in your Zero to the left (for a right twist barrel) might be a good option. I just usually account for it during the shot and usually hold left. It's something I practice enough that it's second nature.


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X2.
Depending on what ballistic calculator you're running it'll account for it if you enable it. I've been using the app "Shooter" for 7 years without a hitch.... the Sig Kilo 2400ABS I'm using now also accounts for it if you have the correct wind inputs.

Mike


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[maninthemaze]

I've got Strelok Pro and it has the option. It shows 3.5" left windage at 1000 yards if I enter a zero wind call. That's with my 195 Berger's at 3080 muzzle velocity. I'll just set it on center. One click left for everything past about 750 yards should suit me and my current abilities. If my math is correct 1/4 moa at 1000 yards is 2-1/2". I'm not a good enough shot to worry about an extra inch at 1000 yards.

One of these days I'll be a good enough shooter that coriolis effect will be my next concern. LOL

Just my 2 cents and worth the price charged.