I used to fireform the 7 TCU while shooting IHMSA matches. Didn't see much if any deterioration of accuracy by doing so, all it did was sharpen the shoulder slightly. As far as the 30 Herret is concerned basically did the same thing, I did however use the 375 SM brass as it was already trimmed and one shot through the FL die and I was ready to go to town. Shot the TCU for standing and the Herrett in production.