| Tatume |
| (.400 member) |
| 04/10/07 06:53 AM |
Re: Building a big bore
|
Quote:
To have that flat trajectory with a large ball, is a wonderful thing. Having the ball within 1 1/2" of the Line of sight to 120yds. makes pin point accuracy a normal & easily aquired result. With the large bore, accuracy merely improves, the more powder used and the trajectory becomes flatter, rather than giving any expra elevation to the ball. The sights must be low, on the barrel for this longer range Point blank sight to work properly. High sights merely add elevation to the ball with more powder, destroying it's point blank range.
This piqued my interest, so I looked at point-blank ranges over different sight heights, using the Sierra "Infinity" software. I've compared this software to several others, and they agree very well.
Using one bullet and velocity, I checked maximum point-blank range for several different heights of sights above bore, in particular 1.0, 1.5, 2.0, and 3.0 inches. I used +/- 1.5 inches as the trajectory criterion for calculating point-blank range. The range at which a bullet will be neither more nor less than 1.5" from line of sight increases as height of sights above bore centerline increases. That is, tall sights improve point-blank range. The software ignores the short period from muzzle exit until the trajectory approaches the line of sight.
Take care, Tom