A seal assembly between a wellhead housing having a bore and a casing hanger, has an inner seal leg for sealing against hanger and an outer seal leg for sealing against housing. An extension extends downward from outer seal leg and is connected to a nose ring having a downward facing shoulder that rests on the hanger shoulder to provide a reaction point for setting operations. A lock ring is retained within interior portion of the nose ring. An upward facing shoulder formed on an upper portion of nose ring contacts the lower surface of the inner seal leg. The shoulder prevents the downward deflection of the inner leg and eliminates buckling due to Poisson effect from the resulting axial force due to growth of the seal legs during setting operations. The shoulder thus prevents crooked or twisted setting of the seal to prevent plastic strain in the seal.