.223 bullet-testing results

After spending almost every night at the range during last week, I’ve now finally come to an end with the bullet testing project. I systemically tested every bullet in two sizes (.223″ and .224″) by shooting one or two 5-shot groups with different pressures from 150bar to 200bar. It took few bottles of air and insane amount of time. I had different bullet designs cast from NOE, Ideal, MP-Molds and one older mold from Ohaus (fifth from the right).

From lightest to heaviest.

..and the results: NOE SP-GC 51gr in .223″ (third from right). It was clear that the GC-version with groove for gas-check performed significally better than the plain-base version. Maybe it’s because spitzer-design as rear-heavy bullet benefits from the groove that moves center mass of the bullet slightly forward.. who knows. Both printed round holes at 100 meters, not a single key-hole.

One strange thing was that 50gr flatpoint bullet from Ohaus didn’t leave perfect round holes to paper, but 51gr spitzer did. It’s strange because usually rear-heavy spitzers require more RPM’s to stabilize during flight than regular shaped bullets.

NOE 51gr Spitzer and Ohaus 50gr

New barrel

After five weeks of waiting (which is relatively short time, compared to firearms), I finally received a new barrel for my AF Escape. Barrel is .223Rem with 1-in-12″ twist rate and has length of 610mm (24″). Made by LW.

Based on my calculations, 12″ twist should be enough to stabilize 50gr bullet even at lower velocities (sub 280m/s / 900fps), so the “chamber” was reamed to accept 15mm long bullets, where most of the 40-50gr bullets land.

Gear update: Laser rangefinder

When shooting at lower velocities below Mach 1, trajectory is more like an arch of a mortar projectile, than a flat straight line. Therefore, especially at longer distances even being off by few meters in calculations can throw you off by several centimeters.

Vortex Ranger 1300 has theoretical maximum of 1300 yards (1188 meters) to reflective target. I’ve successfully measured distances up to 468 meters on a clear day, so performance is more than enough for me.

Vortex Ranger 1300