Beyond High Velocity Loads

How Fast Did They Go?

By now you are well aware that Winchester's High Velocity loads only clocked in at between 1,500fps to 1,565fps. However, handloading data during at least the 1930's shows much faster loads that produce, 20,000cup and as high as 33,000cup. As stated in the previous page, higher than factory load velocities ranged from 1,600fps up to a recorded 2,100fps using at least six (excluding Unique) popular powders. Those powders were Sharpeshooter, SR80, IMR-1204, 2400, Lightning and IMR-4227.  

During 2019 I tested some loads and then tried them in my Marlin 1894CB. The loads were so good, I was able to hit golf-balls at 265 yards. Steady groups less than 18" but a handful came in at about 12", enough to score some golf-ball hits.

I used 26gr of IMR-4227 and a 200gr ACME "Magma Style" hard cast lead bullet sized to .430. During my tests I recorded 1,733fps @ 20,913psi...well in excess of 18,000cup pressures in the "testing" MGM barrel. It looks as if these loads chronographed 1,650fps in the Marlin 1894CB and the pressures are typically a tad less. These loads are not very pleasant to shoot but make great hunting loads.

The Highest Pressure I tested in the MGM barrel was 21,786psi...could very well be close to 30,000cup. This was a 12gr "double charge" of Unique to test an "accidental double charge" of 6gr of Unique as if loading for Cowboy Action Shooting reduced loads. This load was a high velocity load, clocking in at a modest 1,635fps but the pressures are not worth it. Bullseye would have been much worse but I never got a chance to test that powder.