Oehler 33 was a great chronograph, I still have a couple laying around along with several boxes of screens.
Working at Rock Island
Back in the 50s we would shoot Against a calibrated steel disc that would rock in a pendulum. It would have a swing arm that would rock with the plate. The swing arm would stay in the maximum deflected Arc when hit by the bullet.
With this deflection and knowing the weight of the bullet we could calculate the velocity and energy of the bullet.
With the 270 which by the way, was my first rifle for the Christmas of 1947!
I Would get 2800-2900 out of the 130s. Back then I used a lot of 4895 sold in paper bags. I was looking at my old loads and found my most accurate with highest velocity out of IMR 4064 @ 49.5 Grains. So I just stayed with it. We did not have a lot of powders available, or books on the subject. With the new powders now days who knows!
Failure is part of success!
This year will go down in history. For the first time, a civilized nation has full gun registration. Our streets will be safer, our police more efficient, and the world will follow our lead into the future!" -Adolf Hitler,1935"