Without the proper equipment, test facilities, test protocols, and controls this is all just fun discussion and conjecture. Is there anything in the McCoy study to suggest that he tested the custom 1200 fps ammo for accuracy?Ĭlick to expand.Okay, for the sake of discussion, how would you test for the causes of inaccuracies in lower level ammo? How do you determine if the inaccuracy is caused by damaged bullets in manufacturing, or powder loads not measured as accurately as higher end ammo? Or incorrectly placed primer compound? Or all three. 22LR ammo that is supersonic is not affected by transonic turbulence as it slows down? To the zero-yaw drag, but has an insignificant effect on accuracy, retained velocity andĭoes McCoy actually say that the accuracy of. The limit cycle yaw adds approximately 2 percent Slow arm grows to the limit cycle value at about 50 metres range, and the limit cycle Subsonic speeds causes a slow-arm limit cycle yaw of approximately 1.8 degrees. The nonlinear Magnus moment acting on caliber. McCoy says "The purpose of the firings at non-standard velocities was to determine a possible optimum muzzle velocity for minimizing the sensitivity of theīullet to crosswind." He says nothing about shooting it for accuracy.Īmong his conclusions on p.11 is this one, which refers to transonic speeds (890 to 1340 fps) The "nominal muzzle velocities" of these two ammos were 1200 fps and 950 fps. The other ammo was "custom-loaded rounds, whose bullets were similar in shape to the Eley and RWS bullets, but loaded to above and below standard velocities."Īccording to McCoy, this ammo was provided by Steve Chernicky, then head of the US Shooting Team Ultra Match (high accuracy. The only Eley and RWS ammo were commercially produced Tenex and R50, respectively. It's worth noting that the "high velocity" ammo used in this study was not Eley or RWS ammo. Pictures are worth a thousand words right so video has to be even betterĬlick to expand.The reference to the Aberdeen Ballistics Laboratory must be related to the 1990 study by Robert McCoy "AERODYANMIC CHARACTERISTICS OF CALIBER. SK High Velocity Match 1263fps as printed in SK literature After that it is believed that the extra length in barrel starts to slow velocity.Ĭhronograph placed in front of the target at 50 yards I have also read from many experts that the ideal length for a 22lr barrel is 18inches. This was an important piece of data for me as this transition can often cause instability in the projectile. This time I wanted to place the chronograph down range to see if these rounds would make the transition from Supersonic to subsonic before reaching the target. Christensen Arms Ranger 22 16in barrel, Lithgow LA101 20in barrel and a CZ455 Trainer with a 24in barrel. I wanted to make sure I had captured sound results, by trying this ammunition in 3 different rifles all with different barrel lengths. Not only did I want to see what accuracy I would achieve with this ammunition. This ammunition was made in Germany and developed for PRS and NRL22 courses of fire. Though with SK and the quality of their 22LR lineup I was willing to give it a try. In all my my years of shooting 22LR high velocity and match was not something you used in the same sentence. I was able to get my hands on the brand new SK High Velocity match ammunition.
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