Puzzled by .223 Velocities
Q I have enjoyed your articles for over 40 years and use your reloading manual. I have been reloading for a Tikka T3X in .223 and am not sure if I can safely increase my powder charge based on the velocity displayed on my chronograph. I have been using 25gn of AR2208 behind 55gn Nosler Varmageddons and 55gn soft points. The cartridge OAL is exactly as per your manual. My chronograph is a Caldwell Ballistic Precision unit. This load averages only 2880fps, whereas I thought it would be around 3100fps. I tried OSA factory loads with 55gn soft-points and they clocked 2900fps against a published 3200fps from memory. I can’t complain about the accuracy; both factory and handloads are grouping in 0.3 inch average 100yd, but I am curious about the difference in velocity. I know that barrel length may make a difference, but I wouldn’t think that much. I have no idea of the accuracy of the Caldwell chronograph. I have read that AR2206 is better in the .223, but I have a good supply of AR2208 and unless it makes a huge difference, I prefer to keep using AR2208. Any suggestions would be greatly appreciated.
I have a Sako L461 in .223 Remington fitted with a 22 inch Ruger .223 stainless barrel. Your Tikka T3X probably has the same length barrel. I am loading 27gn of W-748 behind the 55gn Nosler Solid-Base bullet for 3196fps and 26gn of AR2208 with the Hornady 60gn V-Max for 3120fps. Your load (25gn AR2208 and 55gn Nosler Varmageddon) should be getting at least 3100fps. My Sako gives the highest velocity with the 55gn bullet and 26gn of AR2206H – 3220fps. I’d keep using AR2208 as you have a good supply of it. The only things I can suggest are that your gun either has a slow barrel or else your chronograph isn’t giving a true reading. You say that the OSA factory loads clock 2900fps in your gun; in my Sako L46 they are doing 3066fps. The Geco 56gn load does 3115fps and Hornady Superformance 53gn load gets 3310fps. Every rifle is a law unto itself. Maybe you could borrow another chronograph to check if the velocities are the same?