Rookie mistake

[GLTaylor]

Depends on what you prefer.
One method is COW (cream of wheat - or grits) uses no projectile, just shotgun powder and a filler at case mouth to hold powder in. Saves one round down your barrel. You still have to fire a full pressure round with projectile to finish.
Other way is to load at starting load level with a bullet - preferably seated touching the lands - to hold the case still during forming.

 

[Nevrsummr]

Depends on what you prefer.
One method is COW (cream of wheat - or grits) uses no projectile, just shotgun powder and a filler at case mouth to hold powder in. Saves one round down your barrel. You still have to fire a full pressure round with projectile to finish.
Other way is to load at starting load level with a bullet - preferably seated touching the lands - to hold the case still during forming.

So glad they asked the question about fireforming. I thought i had an idea of what to do but never knew to jam the lands. Totally makes sense now. Thanks for the explanation

 

[GLTaylor]

Others also make a false shoulder on the brass to do the same thing (hold the case still). It's just easier to me to jam the bullet.

 

[APDDSN0864]

I've never fire-formed before; I'm curious, do you use the starting load or do you put a smaller charge in?

No need to use a reduced load if you are fire-forming using the false shoulder method since, during fire-forming, you are going from a smaller internal volume to a larger internal volume, you can even use a maximum "book" load to fire-form the case. It may even take one or two full power loads to fully form the case to your chamber.
The idea of the false shoulder is to press the case head against the bolt face to properly set the headspace on the newly formed case.

If you're going to fire-forming using the Cream of Wheat(COW) method, you should use a small load of a very fast burning pistol powder such as Unique or Universal.
I have found that, for most centerfire rifle cartridges of medium capacity, approximately 16gr of Unique, case filled with COW to the base of the neck, and a toilet paper wad filling the neck will blow the case out and begin the process. Then, it usually takes a couple of full power loads to fully expand the brass to closely fit your chamber.

Using the COW method, you should be careful to measure your once-fired case against the dimensions of your chamber to detect any that haven't fully expanded lengthwise to avoid case separation.

Ed

 

[Firewurx]

Almost looks like you had the die set to taper crimp and didn't back the stem out before trying to size those down.

 

[Nevrsummr]

Just forgot to chamfer/debur one before i necked down. The other 49 turned out great as i didnt make that mistake again.