Jm 5 Ounce Hand Poured Bar.

It's not uncommon for the weights of older poured bars to be off by a little bit, but 5.5 oz sounds like trouble to me. As far as I know, the weight differences
were never anywhere near that much. Can you get a photo of the bar into this thread?

I know there's been a rash of 5oz counterfeit Engelhards on ebay lately. Has anybody heard anything about that carrying over into J-M 5oz bars?

If they are of the same size, I would highly recommend that you perform a density test through water displacement. You'd need something to measure liquid in mL (milliliter) (a beaker is good). Pour out about 50mL of tap water (however much to drown the bar) and then drop the bar in, measure how much water the bar takes through subtraction. Then, weigh the bar, and take its weight. Divide. grams divided by milliLiter
It should be around 10.49 g/mL.
I hope this helps.

Precious metals are measured in troy ounces, which are 31.1 grams each. Rather than a traditional avoirdupois 28 gram ounce.

I'd be willing to bet that the bar weighs right on the money, 155.5 grams. Which is 5 troy ounces or 5.55 avoirdupois ounces.