07-11-2012, 10:56 PM
Let me preface by saying that I am an amateur shooter with no formal training.
I want to re-establish all the zero distances on my rifles for various reasons and work up some type of dope chart for various distance and bullet combinations. I do not have access to a range past 100 yards at this time. Ideally, I would be able to shoot to each distance and see where I am on paper and then make a note in a dope chart, right? That is not a possibility, so I need to mathematically estimate to the best of my abilities what those results will be.
I have a couple of issues that are concerning me, so I'd like to float these questions out to you guys:
#1. Min & Max PBR is the distance that I can take a shot without the need to adjust POA (assuming a center mass or kill zone hold). Correct? I would think that +/- 5" would yield good results. Would you agree with that?
#2. If I zero my AR 5.56 at 50yds with 55gr M193 (3100fps), then POA=POI again around 245yds. Correct? If I do nothing other than load a 62gr M855 (3000fps) into the rifle and fire again, the 50yd zero is not the same, and the other POA=POI is different. Is there a way to calculate this difference? How much of a difference is that? What about if I am zero'd for the 77gr Mk 262, but decide to shoot the 55gr or 62gr how much of a difference then?
This example is for a 5.56, but it could easily translate to the Grendel & other calibers, especially for someone who hand loads.
#3. Is it uncommon to use a different zero for your scope and your BUIS? I guess the assumption is that with BUIS you are engaging targets at a closer range, therefore your Min & Max PBR may shift?
I realize there are many unique factors that may come in to play, but try and give advice if you can. And, I would love to go out there and shoot and see what happens, but that just isnt feasible right now. I need to have a calculated approximation of expected results before I get to the range. I appreciate your patience with an uninformed shooter trying to get started in the right direction for better marksmanship.
-michaelmew
I want to re-establish all the zero distances on my rifles for various reasons and work up some type of dope chart for various distance and bullet combinations. I do not have access to a range past 100 yards at this time. Ideally, I would be able to shoot to each distance and see where I am on paper and then make a note in a dope chart, right? That is not a possibility, so I need to mathematically estimate to the best of my abilities what those results will be.
I have a couple of issues that are concerning me, so I'd like to float these questions out to you guys:
#1. Min & Max PBR is the distance that I can take a shot without the need to adjust POA (assuming a center mass or kill zone hold). Correct? I would think that +/- 5" would yield good results. Would you agree with that?
#2. If I zero my AR 5.56 at 50yds with 55gr M193 (3100fps), then POA=POI again around 245yds. Correct? If I do nothing other than load a 62gr M855 (3000fps) into the rifle and fire again, the 50yd zero is not the same, and the other POA=POI is different. Is there a way to calculate this difference? How much of a difference is that? What about if I am zero'd for the 77gr Mk 262, but decide to shoot the 55gr or 62gr how much of a difference then?
This example is for a 5.56, but it could easily translate to the Grendel & other calibers, especially for someone who hand loads.
#3. Is it uncommon to use a different zero for your scope and your BUIS? I guess the assumption is that with BUIS you are engaging targets at a closer range, therefore your Min & Max PBR may shift?
I realize there are many unique factors that may come in to play, but try and give advice if you can. And, I would love to go out there and shoot and see what happens, but that just isnt feasible right now. I need to have a calculated approximation of expected results before I get to the range. I appreciate your patience with an uninformed shooter trying to get started in the right direction for better marksmanship.
-michaelmew