Q: 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 ammo and handloads are grouping in 0.3 inch on average at 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 enjoyed your articles for over 40 years and use your reloading manual.
A: The only things I can suggest are: your gun either has a slow barrel or else your chronograph isn’t giving a true reading.
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.
Loading 27gn of W-748 behind the 55gn Nosler Solid-Base bullet achieved 3196fps, when you could get W-748.
26gn of AR2208 with the Hornady 60gn V-Max managed 3120fps.
My Sako gives the highest velocity with the 55gn bullet and 26gn of AR2206H — 3220fps.
Your load (25gn AR2208 and 55gn Nosler Varmageddon) should be getting at least 3100fps. I’d keep using AR2208 as you have a good supply of it.
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?