Steel shot in Beretta choke
When using steel shot, we suggest that you only use choke tubes marked with the "SP" (Steel Proof) identification on the side, and that you use the most open choke system possible. To this end, any chokes up to and including a Modified constriction are suitable for steel shot. The use of steel shot in constrictions tighter than a Modified risks damage to your barrel, but will most frequently result in a less than effective shot pattern. This is due to the properties of lead, as they compare to steel. Lead shot requires a tighter choke, as the material is soft and malleable, resulting in deformed pellets, which facilitate an eccentric flight pattern. Conversely, steel does not share these properties, and is much harder than lead. This characteristic results in a naturally straight flight pattern. Moreover, if steel is tightly compacted, the pellets may potentially "ricochet" off of one another, resulting in a less than satisfactory shot string and pattern. As with any shotgun, always be sure to check your choke tubes during use to verify that they are tight in the barrel. Loose choke tubes can cause barrel damage. Moreover, ensure that the chokes that you are using are Beretta OEM, and designed for your model of firearm.