Fire Forming

[18yrdeputy]

Have recently had my action blue printed and a custom Krieger barrel installed (23” / 6.5 CM), stayed with the same caliber. I’m getting ready to begin working up a load for this new chamber and I began reading about fire forming brass, to my new chamber, using what a lot are referring to as the “cream of wheat” method. My curiosity has been raised simply due to I’m needing to know at this point how much to bump my shoulder back on load work up. All the rounds u currently have are set up for my old chamber/barrel. Not particularly wanting to go waste money on factory ammo or loading (wasting materials in my opinion) just for a few pieces of brass formed to my chamber, just so I know where to bump the shoulder. Anyone have any other suggestions ???????

Im looking to build a load around a 140gr bullet

 

[jasent]

If your old brass chambers just start load development, if it doesn’t chamber then bump the shoulder a couple thousandths till it will. Then load away. Cleaning burnt cream of wheat out of the bore is a pain!

 

[Missalot]

Why not FL resize 3 rounds, shoot them, and see how much on average (should be a tight average) your case expands? Then you should know how far to bump the shoulder.

 

[Steel head]

I just load a cheaper bullet with a moderate load of powder.
You’ll get your rifle close to zero’d, some barrel break in and some once fired brass.

Fired brass will jive well with your chamber and give all the data needed to reload and barrel probably won’t change now while your doing development.

 

[AIAW]

If your old brass chambers just start load development, if it doesn’t chamber then bump the shoulder a couple thousandths till it will. Then load away. Cleaning burnt cream of wheat out of the bore is a pain!

It's not guaranteed that a shoulder bump will ensure chambering. If the web expansion of the old brass is larger than the dimensions of the new chamber then only a small-base die will cure that.

 

[jasent]

It's not guaranteed that a shoulder bump will ensure chambering. If the web expansion of the old brass is larger than the dimensions of the new chamber then only a small-base die will cure that.

True but if that’s the case he still would not be able to ff with cow method with out doing so first

 

[Howland]

If your old brass chambers just start load development, if it doesn’t chamber then bump the shoulder a couple thousandths till it will. Then load away. Cleaning burnt cream of wheat out of the bore is a pain!

+1!

The beauty of this method is that if you start with fired and unsized brass and it does not chamber (or you feel extra resistance closing the bolt handle), just go to brass sized for the old chamber. If that has extra resistance, the new chamber is smaller. If not, use the fired and unsized brass.

Then you can incrementally adjust your dies down to get exact sizing. A 5° turn is almost exactly .001." I use a compass and a sharpie to put reference marks on the die and press.

It sure beats taking new brass and firing three times to get full case expansion.