Raimey, you might have misunderstood, the chambers on the gun you posted were 18.7mm which equals .8362. The chambers on the one I am looking at are 19.0mm=.748
I measured some Gamebore 16 ga and the hulls are Cheddites. They were fairly consistant at .741. Loaded shell measured 2 1/8" with a fold 6 crimp.

I won't get a chance to look at it today, maybe later this evening before they close, and I will look at the weight stamp.

David