KGII Halfpence can have a wide range of readouts due to the ones that were counterfeited were cast and used much less copper, some are pewter/lead, but most are a mixture of copper and other base metals. KGIII Halfpence were for the most part struck, not cast and for those the counterfeiters basically used copper, but made sure the weight of the coin was at least 10% or more less in weight, that is how profit was made from counterfeiting. So weight of a KGII can and cannot be used to say counterfeit, since adding heavy metal like mixture of lead can bring the weight up close or even above Regal weight, but for KGIII, almost all counterfeits are underweight since they were struck, not cast and were for the most part copper like Regals, but much less of it, thus weight is a big factor in helping to determine counterfeit, but a KGIII can read rather high on any detector. Your KGII sounds like it is a counterfeit, of which 40% or so that circulated in this country were counterfeit. KGIII Halfpence are without a doubt over 90%+ counterfeit that we find.
