This paper patched bullet weighs a nominal 530 grs. The diameter can be ordered either as 0.458″ or 0.468″. This SKU is for the 0.458″ diameter. It is important to know the groove diameter of the rifle since it can vary considerably. Almost all Mk IV will require a 0.468″ bullet. If blackpowder is used, it is advised to use a grease cookie under the bullet to keep the fouling soft. This is not needed with Trail Boss. The bullets are a moderate hardness with a Brinnell value of 11.5 – 12.5. By comparison, wheelweights are typically 9 and Lyman #2 alloy is at 15. This price is per/50 bullets. Shipping weight is 1850 g/50 bullets. To protect the paper patch, the bullets are shipped in styrofoam packaging.