A message about loading. I used 777 power in cartridge guns.

After the last shooting session, I noticed I had a little trouble opening the gun on one shot. I examined the primers and found they were pushing into the firing pin hole. Scared me. I looked at previous loading and the primers were not deformed like this.
I took the rest of the loaded cases and pullet the bullets and found that I had over compressed, somehow, the power. In some cases it was a solid mass.

The warnings from Hogdens is to NOT compress. I believe I spiked pressure with the compression. I must have miss judged the powder and seating depth.
I am backing away from the 777 until I figure out what happened. I will likely switch to black or 4198 loads.