It depends on state law, but under federal law, a transfer of non-NFA firearms under a will is generally exempt from the interstate transfer limitations. See 18 U.S.C.A. § 922(a)(3), (a)(5).
NFA firearms may be transferred tax free in these instances on a Form 5, but the provisions of the NFA otherwise apply to the transfer.
Note that only the actual bequest or transfer by intestate succession is covered. For example, if the father leaves everything to his wife, but then the wife gives the firearms to a child, only the first transfer is likely subject to the exemption (not getting into the law of disclaimer).
Again, this is not legal advice and no attorney-client relationship is expressed or implied by this post.