Tallday 10 Posted April 9, 2014 Hi all. I am shooting my first bolt action match Saturday. I will be using my k31 and gp11 surplus ammo. My problem is I have changed the rear sight since last time I shot it. I have no time to get to the 200 yard mark until the match. Lucky I get 5 minutes of sight in before the match starts. But I can get it to the 50 yard indoor range at GFH. I would like to know if sighting in at 50 yards what would be the difference when out to 200 with the point of impact of the 7x55 swiss? I know you reloading guys have a good knowledge of ballistics and could probably get me on paper. Thanks for any help. Sent from my SPH-L900 using Tapatalk Quote Share this post Link to post Share on other sites
Jon 264 Posted April 9, 2014 Assuming sights are 1/2" off the barrel, a k31 shooting gp11 should drop roughly 7.5" at 200yds using quick and dirty numbers found online. Quote Share this post Link to post Share on other sites
Jon 264 Posted April 9, 2014 Also, I used the Hornady Ballistics Calculator(try google, having trouble hyperlinking) and found that GP11 fired through a K31 achieved roughly 2560fps and had a ballistic coefficient of .505 - .514. Quote Share this post Link to post Share on other sites
Tallday 10 Posted April 9, 2014 Thanks Jon. So I should zero about 5 to 7 inches above center at 50? Sent from my SPH-L900 using Tapatalk Quote Share this post Link to post Share on other sites
Jon 264 Posted April 9, 2014 Thanks Jon. So I should zero about 5 to 7 inches above center at 50? Sent from my SPH-L900 using Tapatalk If you can measure the height of your sights over the bore you can get a bit more precise. ETA: at 1" over bore, the numbers work out to 6", at 1.5" over bore, it's 4.5". Quote Share this post Link to post Share on other sites
Tallday 10 Posted April 9, 2014 I just used the sight you linked and put in some data found on the Web guessing that the sight hight would be around .5 inches .looks like if zero at 50 then -7.5 at 200. Sent from my SPH-L900 using Tapatalk Quote Share this post Link to post Share on other sites
Tallday 10 Posted April 9, 2014 So if I zero 7" above at 50 then should be close at 200 right? Then I can fine tune with my sight in time. Sent from my SPH-L900 using Tapatalk Quote Share this post Link to post Share on other sites
Jon 264 Posted April 9, 2014 So if I zero 7" above at 50 then should be close at 200 right? Then I can fine tune with my sight in time. Sent from my SPH-L900 using Tapatalk Yes. Quote Share this post Link to post Share on other sites
Tallday 10 Posted April 9, 2014 Thanks ... This saved me a dozen or so rounds and some cuss words.. Sent from my SPH-L900 using Tapatalk Quote Share this post Link to post Share on other sites