Most barrels are made of much milder steel than what is used for Steel shot. You should assume that your barrel won't stand up to any of the shot made as a substitute for lead, until proven otherwise!
The problem with all of the non-toxic substitutes for steel shot is how costly they are, and the availability, both obviously linked together.
You can use Hevishot- if you can find it--- by using the heavy Plastic shot cups sold by Ballistics Products, and possibly other suppliers, designed to be used with steel shot.
You can also make your own shot cups, but they will need to be made of heavy paper, or (index) card stock, to protect your barrel from being scored by the pellets as they move out of the barrel on firing.
How thick they need to be( the shotcups) depends on the size of the shot you choose, the brand you choose, and the gauge of your gun. Generally, the larger the size of the shot pellets, the thicker your cup needs to be.
How long the cups need to be depends on the amount of shot you intend to shoot and the gauge of your gun.
You may also want to experiment with finding ways to cause a separation of the cup from the shot when it leaves the barrel. Ideas tried here that work including putting a "tail " on the cup, that acts like a drag-chute, and cutting slits in the front of the cup, so that the "petals" fold out and act like an air brake. IN barrels that have choke tubes, or fixed choke, the choke complicates the use of either the plastic or paper shotcups because you have to fit the cup down through the choke. You should probably need to use some kind of OP wad behind the cup so that the cup can be small enough in diameter to fit easily through the choke.
Jug-choked barrels do not pose the same problems regarding fit, in using either the paper or plastic shotcups.
Some members have been buying commercial shotgun shells loaded with some of the new non-toxic shot products, and taking the shot from these shells to use in their MLERS. Considering the bag limits imposed on migratory Waterfowl, which require the use of non-toxic shot, many BP shooters simply don't use their BP guns to hunt Waterfowl any more. Trust me when I tell you that the US fish and Wildlife service has felt the Pinch from the drop in revenues from the sale of licenses and "stamps", as well as excise taxes on ammo.
And all this because of a faulty reading of some preliminary data that later was proved to be false, and does Not support the claims that lead shot was being ingested by waterfowl and killing them with lead poisoning, as the result of shot laying in shallow water, or on the open ground. Later studies indicate the mortality from wounded waterfowl easily explains the decomposed carcasses that earlier, unskilled students had examined and falsely attributed to the ducks and geese INGESTING lead shot. Later studies show that Lead shot quickly oxidizes with calcium present in the water, or with Iron present in the water and soils, to form a thick, hard crust around the lead pellet. If eaten, the pellets pass harmlessly through the bird's digestive system. But it would be easier to get water to flow uphill than to get Congress to reverse a bad law. :hmm: :thumbsup:
