My question is can I make 375 win brass into 7-30 waters brass in one pass with imperial sizing wax as case lube.

I tried this many years ago and the 375 brass was too thick, the necks needed to be turned down.
They would not chamber, lucky for me they didn't.
I could have run the pressure up!
Greg

You can use 375 Win brass but you need to check and see what the OD of the case mouth is on a peice of fire brass out of your gun. This will tell you if you can use it. The 375 Win brass is .304 at the mouth of one made into 7-30 Waters you need to be .003 to .004 large on the fired case so you need to be .307 min.and it will work. I use the 375 brass made into 7-30 Waters and it works good and no you can not make it with just a 7-30 FL die. If you would like to know how to make it e-mail me.

I am sorry but,you are wrong you can just run 375Win brass in the FL 7x30 die and start loading and shooting it.If not then you guys tell me why I shoot 1/2" groups @140yrds.I never had to turn my necks or anything like that.Just keep it safe and load it low and work up.

Excuse me for butting in,why not use 30-30 brass
to form the 7-30 Waters brass?

Wc

30-30 brass has a 45,000 cup level the 375 brass has a 50,000 cup level.30-30 brass is fine but,it is not as strong as the 375 brass.Also if you use 375 brass you dont have to fireform the case as much.

Drichi,
I make 7-30 waters brass from 375 win for my TC by simply running the 375 brass into a 30-30 die first(make sure there is no dents in the neck area before this first step)back die off until the neck length matches the 7-30 neck length, then deburr inside and out and run into the 7-30 waters die, trim to square the mouth then load. You will have to work up new loads in this brass because it is thicker, no fireforming needed. There is virtually no loss of brass with this method. If your're shooting a TC watch your head space and adjust accordingly. You would be far agaid purchasing one of Mike Bellms head space indicator to adjust your dies shooting TC's.
Albert