Buying one bolt head that's the specified length is a total crap shoot. There are soooo many factors involved fitting bolt heads. Please read Peter Laidler's article on bolt fitting here and you'll see what I mean. This is why I refuse to sell bolt heads anymore. I will fit them if someone is in need but only to MoD specifications. I NEVER use SAAMI specifications. They are too tight and there's no supply of long bolt heads to be had because so many have upgraded the headspace on their rifles needlessly.