October 01, 2009
Bullets Do Odd Things at Different Ranges
By David E. Petzal
“It’s better to go broke at the range than it is to make a fortune in the shop.”*--Christopher Self, Alabama machinist, designer and rifle nut.
Last week, I got a further lesson on the folly of attempting shots at long range without actually testing your equipment beforehand. Shooting at 300 yards, a 165-grain polymer-tipped bullet which had shot splendidly at 100 and 200 yards turned in a group with a vertical spread of 7 inches. There was no horizontal dispersion at all, but the slugs were all over the place up- and down-wise.
According to some balistically sophisticated friends of mine, there are three possible causes:
1. The polycarbonate tips melted off by the time they got to 300 yards and caused variations in the bullets’ flight.
2. The bullets were stabilized at 100 and 200 but by the time they reached 300 their loss of velocity destabilized them.
I saw a similar occurrence with a .300 Weatherby Magnum which shot handloads using Norma MRP very accurately at long range. When the MRP ran out, I worked up a load with RelodeR 22 which gave about 50 fps less velocity and nearly identical accuracy. At 100 and 200, fine. At 300, all over the target. I think that missing 50 fps was responsible, or maybe it was Lucifer.
Bulllets do odd things at different ranges. I am reminded of Ross Seyfried’s .300/416 wildcat, Miss America, which was built by Ultra Light Arms. At 100 yards it was all the gun could do to shoot 4-inch groups, but at a measured mile it put five shots in a group you can cover with your hand.
*This has nothing to do with shooting at long range, but I liked it so much I pass it along to you. And of course Chris is right.