One of my favorite loads for 45 Colt is the 260 LFN bevel base bullet with 8.5 grains of Universal and a CCI 300 primer. This gives me about 950 fps and good revolver accuracy.
I recently bought a Marlin 1894 rifle in 45 Colt and wanted to try it out, even thought it was about 10 deg F outside.
The groups I shot at 100 yards were about an inch side to side, but had a lot of vertical fliers that spread the group 4-5 inches high. 3/5 were usually close together with a couple of vertical fliers.
Could this be due to inconsistent ignition with standard primers in cold weather?
I would like to try some magnum primers to see if it remedies the situation, but I am not sure if they are OK to use with Universal powder. I know they are recommended with slower powders like H110, but realize that faster powders like Universal powder may be a whole different game.
Is it safe to use magnum primers with Universal?
Tom