First, let’s talk about firing shotshells through a rifled barrel. People have written books on rifling and the effects of twist rate on speed and accuracy. It is pretty interesting and given enough money and time you could probably spend a year trying out different combinations to figure out what works best for the firearms or pellet guns you own. To clear up the most obvious concern, NO, rifled barrels were not made for shot rounds. This comes down to the principle of centrifugal force. A single-centered pellet benefits from a rifled barrel, but the centrifugal force has the opposite effect on shot rounds because most of the round is off-center.
With that said, how much impact does using a rifled barrel have on a shot round? At a typical 10–15-foot distance that you might find in a home defense situation, a lot less than you would think. I use the #8 shot in my shot rounds and a smooth bore shotgun the typical spread at 15 feet is 10”, whereas in the Zeus it is more like 3 feet (A little over three times greater). For a typical OO buck round (A round filled with 32cal balls that weigh around 50gr each) they will spread out around 12” fired from a typical shotgun. The same round fired from a rifled barrel Zeus 72 has a spread of 16”. Here are my takeaways from this information.
1. Shotguns have been suggested as home defense weapons for years, you fill a round with bird-shot and it inspires a bad guy to go the other direction. It also has the added benefit of it being much less likely to injure unintended people in other rooms. I would also argue that I would prefer a 3-foot spread of 15 feet because this pattern will cover wall to wall in a typical hallway, making it more likely you will hit your target.
2. The centrifugal force effects on heavier pellets are less pronounced than on the much lighter shot rounds. So, an OO Buckshot round at 15 feet fired from a shotgun has a spread of about 12”; whereas the same round from a Zeus 72 spreads around 16”. I think this is a fairly respectable spread for OO Buck and I would not change a thing.
3. Should you desire to have a round that will be on target as well as fairly lethal potential, then you go to specialty rounds. While I have started with a few types of rounds, the sky is the limit for different types of shot rounds. For instance, a round with (1) 50cal ball @ 175gr, (3) OO Buck 32cal, 50 gr pellets, some size 4 pellets, and the rest in shot totaling out at 650gr would be a devastating round.
4. For the future of shot rounds, only our imagination will tell what will be made. At the request of a friend a few years ago I made ceramic flats that each had a roller bearing in them, after the CNC mold was made it was a quick and simple process. When stacked in a 12ga round the bearings never lined up which meant on the impact the ceramic shattered and the roller bearings all took different paths. Recently someone mentioned rock salt. This is a no-brainer, I already make a rocksalt and ghost pepper round for the Umarex HDS 68, so this would be a quick and simple round.
The final thing I will leave you with is cost, these are not cheap (I get it), but they are very time intensive to make. I will be including other 72 pellet samples with every shotshell round order and if I figure out a simplified way to make these quicker, I will pass on the savings.