Why heat treat, may I ask?
Crimp adds virtually nothing to neck tension. About the only thing it does is keep the bullet mechanically locked just a little longer should a force sufficient to overcome the tension be applied. Useful for bumping the burn rate of the powder a tiny bit. I generally run about .002" tension with my levergun ammo, and a medium roll crimp in the groove. With a single shot, I see no reason to crimp at all unless the powder and jump distance demonstrated a preference through experimentation. If you use a seat/crimp combo die you can adjust the die body to reduce the flare to just graze the chamber neck walls per 35 Shooter's recommendation above at the same time you seat the bullets.
I cast a batch of NOE 35-200 today and have them prepped for heat treating. I used my Stoney Point tool with one of the bullets to check how far out the bullet could go before engagement. If I back off some and use this measurement I will not be able to crimp in the groove. This is a single shot CVA Scout. Wondering if neck tension will be enough if I crimp just enough to iron out any flair at the case mouth. Using M Type die. Other than my 1895 this is the only other rifle I'm attempting to shoot cast in.
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