Hi Im building a Vietnam M70 clone but its a 308 Target rifle not the 30-06.I ordered a set of Unertyl type blocks for it.It seems the front Barrel block is 1/4" below the rear block that sits on the front receiver ring.Should they be even or should they be like that?Are there different height front blocks?I have left some messages with the guy in the US but he is one of those super patient people and hasnt answered yet.Dave