I have casted some .356" bullets for loading in a 9X19 using a Lee TL356-124-2R mold. I tumbled lubed them with the Lee Alox lube that I cut down a tad with mineral spirits. I started with 4.5 grains of Unique and Fed. 100 SP primers. The Lee data says starting load of 5.3 with a 125 lead bullet but my Lyman book says 4.4 starting with a RCBS molded bullet so I went with the more conservative data somewhat.
I shot 3 of these loads and I got some of the flattest primers that I have ever seen on any cartridge.
Any Ideas on what is happening? With jacked bullets and 5.1 grains of Unique, the primers look fine.
The bullets are casted from wheel weights. I am thinking they might be bit too soft. These bullets seem to shoot descent and extracted fine but i am thinking I've got a lot higher pressures than I should.

I am a newbie to casting for the most part although I have been dabbling for a while.
Any thoughts or suggestions are welcome.

Are you crimping those cast bullets and creating too much headspace? This condition can allow primers to back out then flatten off as they are reseated by the case thrusting back onto the bolt head. The primers then give an impression of high pressure when there is not.

Eagle,
Yes, I am using the Lee "Carbide Factory Crimp" die which is a taper crimp. I don't believe it is a headspace issue as I took the barrel out to visually check for leading. I also placed a loaded cast bullet round in the chamber to check for that very same thing and it appeared to headspace fine.
According to the Lee instructions, it is impossible to over crimp the case with this die. (shrug)
I guess I will have to chronygraph a few rounds and get a better picture of where I am at.

Rae,

All of the Lee factory crimp dies I've run across produce a roll crimp rather than taper. Is the crimp tapered for sure and not rolling into the crimp groove/cannelure? Taper crimp and roll crimps dies are not the same nor are the results of their use.

Craigster,
I looked at the crimp (with a magnifying glass AND glasses on at the same time) and it appears to be just a taper crimp. I tried a loaded case in the barrel while I had it out of the pistol and it looked fine, head-space wise. Maybe I missed something. I will check again.

I will also try some rounds without using the Lee Carbide Factory Crimp die and see what happens.