My knowledge is limited in this area but I was wondering how you know you are getting "pressure spikes"? Do you have some type of pressure testing system? Just curious as I'm developing loads for a .450/.400 3-1/4" now with Hawk bullets and haven't seen any pressure signs yet.

I've used Hawk bullets consistently in a .40-82WCF and they have performed flawlessly. Great accuracy and knockdown punch.