I dropped my Chronograph the first of Dec. and thought I broke it. So I put it back on the tripod and shot a few rounds and did not pay attention to the exact numbers that came up, but just glad to see numbers. Every since then I have had above average velocity recordings. Well some of you have questioned my velocity numbers and even have me doubting or wondering myself. So I ordered a new Chronograph and I will be able to compare my 257-300Wby and my 350 Rem mag. This ought to be interesting. I decided to do this when I fired my 22-250 last week and with factory loads recorded 175fps above what I use to get and my handload was 207fps above my average. This should be interesting.
Well, I went to the range this morning and boy was I ever enlightened by the results. Of course I did as Smokin advised me to and lined them up in a row. Well the old chrono was well above the new chrono in velocity. I stood there looking at them wondering why is this happening???? As I looked at both of them in a row I saw it and it jumped right out at me, why had I not noticed it before. Having them both in a row caused me to notice that the old chrono was not folded out flat like the new one. So I took it off the tripod and where I had dropped it in December it had bent the sheet metal just on the end that you fold down and was not allowing the chrono to completely open up an lay flat. This meant that the rear photo cell was pointing in a slight angle toward the front photo cell and this shortened the distance between the two. That means the old chrono was recording the speed over a shorter distance that it was not calibrated for so the speeds were faster. Here are the real results of my 257-300Wby with 2 grains below max load for my rifle and also my 350 Rem Mag. at 2 grains below max load.
Average 86grs Retumbo 100gr TSX
Accuracy of the load which was outstanding
RL-25 average at 2grs below max 100gr TSX
Average for 350 Rem Mag 225gr Sierra
Well now we know why I was getting such high velocities and also know what the truth is. I think I will stay with the 3850fps because the accuracy was so good. With the 350 Rem Mag I will try 61.5grs of WW748 and see what happens.