I am building up and old LA that was 7mm Mag and converting to .243Win. My question is regarding the bolt head. I know I need to replace the 7mm head (.532") to a .308/.243 head (.473"), but in my research I am only finding the .308 head labeled as a SA. Is this a generic description because that caliber is usually offered as a short action and if I purchase it will it work on my long action bolt? If it won't work with the long action, a .30-'06 head should, right? And if I order through PTG (standard bolt face), do I need to get the bolt alignment cut seeing it is a flat back action?

Thanks in advance for the answers.