I am certain it is one of the Symphyta families and not Ichneumonidae. I cannot really be certain whether it is Xipyidriidae or Siricidae. I am not a hymenopterist, so...
In all honesty, I tend to subtract about half the recorded size of what less experienced people attribute to their finds and even then it may be overestimating the true size... Similarly, the less experienced tend to underestimate the size of flocks of birds. A fact of life, I suppose.