New York Firearms Forum banner

500 Yard Ranging

966 Views 6 Replies 3 Participants Last post by  joesmoe_6
I have a question regarding setting up for a 500 ard Competition. Can I use a ballistics program and enter the following parameters Bullet Weight, BC , sight over bore , etc and use 500 yards as the sight in distance. Calculate a firing solution based on the criteria ive given and use the 100 yard rise value to set up the scope for the 500 yard shot. By that I mean at 100 Yards the bullet is 7.5 inches high. If I set up my scope so that it shows 7.5 inches high at 100 yards will I be right on at 500 Yards ?
1 - 2 of 7 Posts
If all your inputs to the ballistics calculator are correct (mass, velocity, BC and sight over bore most important) you should be pretty close. You need to make sure that your scope crosshairs are level to the scope base and that the crosshairs are level when you adjust your zero. Most calculators probably do not include spin drift, but that is not likely to be a large factor at 500y.

Maybe we are saying the same thing, but you do not want your scope showing high at 100, you want your POI 7.5" high at 100 yards.
. Yes I set the scope up using a laser bore sighter showing the point of impact at 7.5 inches whith the cross hairs 7.5 inches lower than the laser dot.
You need to fire the same live rounds that you plan on using at 500, and then adjust the scope so that your rounds are impacting X inches above your point of aim.

Using a laser bore sighter will get you onto the target backer at 50 or 100 yards, but it is not going to show you the real POI. Laser guides are not usually exactly centered in the bore, so either your elevation, windage or both could be off. Also, even if the bore sighter is exactly centered, it shows the bore axis, not the POI - you already have some bullet drop at 100y, although not much. Live rounds also put the barrel under stress so it flexes to a small degree causing the bullet to impact in different places with different loads. With a sporter contour barrel, I can get my POI to move nearly 2MOA with loads that vary by a grain of powder or so.

The short answer - you need to shoot the live rounds you plan to use at 500 if you want to get close to paper.
1 - 2 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.