johnnyk
Well-Known Member
Set my chronograph up Wednesday to check a new load in my 7Mag. I decided to check the zero on my .243 while I was at it. The load for the .243 was the 95gn Ballistic Tip ahead of 44.0gn of VihtV N560/BR2. I checked it in Nov09 and it averaged 3088fps, so I was suprised to see it shooting above 3200fps. The first three shots were 3271/3278/3247 (3265fps). The temperature was 51deg. I thought, Hum?
I went to the 7mag next. The previous load had been with a 150gn Ballistic Tip with 63.5gn of IMR4350/9.5M and I was getting 3234fps in Nov09. I worked the load last week up to 64.0gn of IMR4831/9.5M and accuracy was great. The five shot string was 3265/3301/3281/3336/3321 (3300fps). The first blame was put on the chrono's battery.
I went back to the .243 and shot a 6 shot string. They were 3191/3206/3217/3184/3230/3183 (3201fps). I thought WOW, wouldn't that be great. I know something is not exactly right but haven't figured out what that might be. The distance from the muzzle to the chrono was 10-12ft as normal. I don't think it was the temp as that would cause lower velocities. The only thing I can attribute these higher velocities is the angle of the sun. It was approx. 5:00-5:45PM, which at that angle and time it's almost down behind the mountain here. I check the batteries voltage and it was 9.7volts, more than enough. In the past a low voltage has resulted in very low voltages during range sessions. What do you guys think? JohnnyK.
I went to the 7mag next. The previous load had been with a 150gn Ballistic Tip with 63.5gn of IMR4350/9.5M and I was getting 3234fps in Nov09. I worked the load last week up to 64.0gn of IMR4831/9.5M and accuracy was great. The five shot string was 3265/3301/3281/3336/3321 (3300fps). The first blame was put on the chrono's battery.
I went back to the .243 and shot a 6 shot string. They were 3191/3206/3217/3184/3230/3183 (3201fps). I thought WOW, wouldn't that be great. I know something is not exactly right but haven't figured out what that might be. The distance from the muzzle to the chrono was 10-12ft as normal. I don't think it was the temp as that would cause lower velocities. The only thing I can attribute these higher velocities is the angle of the sun. It was approx. 5:00-5:45PM, which at that angle and time it's almost down behind the mountain here. I check the batteries voltage and it was 9.7volts, more than enough. In the past a low voltage has resulted in very low voltages during range sessions. What do you guys think? JohnnyK.