Velocity Variation
Hello, I've been a member of a Bench Rest shooting club for some time, and I've noticed that I'm having problems with velocity variation with my ammunition. Most of my shooting colleagues have a stability difference of one or two feet per second, which I can't seem to achieve. So I asked a few people how they do it, but it seems to be a closely guarded secret. I checked the velocity of my ammunition with a Doppler radar, and I have a velocity variation between 2650 and 2800 feet per second. I'll explain how I reload. I use the same type of casing, .223 Rem Sellier Bellot, which I clean with a thumbler. Then I remove the old primers, then I clean the pocket primer and also use a flash hole deburring tool to remove any burrs that may be present inside the casing. Then I use a .224 mandrel expander for the neck of the casing. I use 20.5 grains of Hoggdon 335 powder and a 68-grain Hornady BTHP bullet, ultimately achieving a COAL of 2.260 on each of my rounds. But it doesn't seem to be working; I still have a significant velocity variation... Could you please solve my problem? I would be very grateful. Thank you.
Just checking - have you tested your ammunition / velocities with another rifle to confirm that it is the ammunition which is causing the variations? 150 fps or 5% is quite a lot ... Then also checking: Are you using a powder which burns entirely before the bullet leaves the muzzle? If not, this can also be an issue. Last question: Are you using press loads, i.e. loads with a fill rate >100%?