In reading about the plains rifle, quite often the bore size was mentioned in "balls per pound" rather than in terms of "calibre" as we think today. This was a carry over from the days of the Kentucky long rifle.
So, I got curious and decided to weigh some .50 and .54 'calibre' balls which are in fact .490 and .530 in diameter, using my Home Ec teacher wife's kitchen scale.
I weighed some swadged Remington 'Gold' .490s, some generic cast .490s purchased at a BP RV and some swadged Hornady .530s. Here's the results:
- Remington .490 'Gold': 44 balls to the pound
- BP RV cast .490: 42 balls to the pound
- Hornady .530 swadged: 34 balls to the pound
One of my Hawken reference books (Hanson) states that records show most rifles were made in the 32 to 40 balls to the pound range.
Larger bores were 'special order' and often in rifles whose barrels had been "freshened" - bored out to the next larger diameter and re-rifled.