Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Accuracy versus velocity
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="LRNut" data-source="post: 1867911" data-attributes="member: 3230"><p>I notice no one has commented on the fact allowable wind reading error is driven far more by accuracy than by velocity. For example, let's say I am trying to hit a 10 inch target at 800 yards. I have two cartridges shooting identical bullets (suppose a 7mm 195 Berger), but one shoots .4 MOA @ 2800 and the other one shoots .8 @ 3000. The 2800 fps bullet is going to group 3.2" at 800 yards, which if perfectly centered, leaves 3.4" on either side of the widest bullet impact. At 800 yards the slower bullet is drifting 3.2" per mile of wind speed. So your allowable error to keep that entire group size in the 10" vital area is 1.1 mph. The faster bullet drifts 2.8" per mile of wind speed, but since the group is 6.4" if perfectly centered, you only have 1.8" on either end, which means you must estimate wind speed to within .64 mph. The slower but more accurate load has TWICE the allowable wind reading error. I will take that every time.</p><p></p><p>Bullets don't travel in a straight line; half hit to the left, and half hit to the right. Half are higher than your point of aim and half are below.</p><p></p><p>Some of you are probably thinking you can hit that 10" target quite frequently and yet cannot estimate the wind within 1 mph. Remember, if the wind is left to right and you call it too high by 1 mph (pushing your "group" 3.2" left), there is a 50% chance the bullet will be one that hits to the right of your point of aim, potentially resulting in what looks like a perfect wind call.</p><p></p><p>One thing is rather obvious: at some point your ability to call the wind and/or shoot a small enough group at extended ranges will result in wounded animals. You can work up loads and spin on custom barrels till the cows come home, but unless you are out there shooting at LR at least weekly, you are going to suck at reading the wind. And if you are shooting in a mirage-less condition, you are really going to suck.</p></blockquote><p></p>
[QUOTE="LRNut, post: 1867911, member: 3230"] I notice no one has commented on the fact allowable wind reading error is driven far more by accuracy than by velocity. For example, let's say I am trying to hit a 10 inch target at 800 yards. I have two cartridges shooting identical bullets (suppose a 7mm 195 Berger), but one shoots .4 MOA @ 2800 and the other one shoots .8 @ 3000. The 2800 fps bullet is going to group 3.2" at 800 yards, which if perfectly centered, leaves 3.4" on either side of the widest bullet impact. At 800 yards the slower bullet is drifting 3.2" per mile of wind speed. So your allowable error to keep that entire group size in the 10" vital area is 1.1 mph. The faster bullet drifts 2.8" per mile of wind speed, but since the group is 6.4" if perfectly centered, you only have 1.8" on either end, which means you must estimate wind speed to within .64 mph. The slower but more accurate load has TWICE the allowable wind reading error. I will take that every time. Bullets don't travel in a straight line; half hit to the left, and half hit to the right. Half are higher than your point of aim and half are below. Some of you are probably thinking you can hit that 10" target quite frequently and yet cannot estimate the wind within 1 mph. Remember, if the wind is left to right and you call it too high by 1 mph (pushing your "group" 3.2" left), there is a 50% chance the bullet will be one that hits to the right of your point of aim, potentially resulting in what looks like a perfect wind call. One thing is rather obvious: at some point your ability to call the wind and/or shoot a small enough group at extended ranges will result in wounded animals. You can work up loads and spin on custom barrels till the cows come home, but unless you are out there shooting at LR at least weekly, you are going to suck at reading the wind. And if you are shooting in a mirage-less condition, you are really going to suck. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Accuracy versus velocity
Top