TSS is harder than lead , bismuth , hevishot , steel shot and the barrel of the gun itself -TSS will/may score choke tubes
brownings website .......
All current Browning shotguns with the Invector or Invector-Plus choke tube system are fully steel shot compatible with current factory loads. However, there are limitations to the compatibility of many older Browning shotguns with conventionally choked barrels. In certain models, shooting steel shot may cause a slight "ring bulge" just inches behind the muzzle or irreversible damage or harm to the shooter depending on the firearm. Accordingly, our recommendations concerning the use of steel shot in Browning shotguns is as follows
3. DO NO USE ANY STEEL SHOT LOADS:
The Belgian-made A-5, Superposed, Leige, and other Belgian Over/Under models, Double Automatic, American-made A-5 and all other models not listed in category 1 or 2. Note: Belgian Auto-5 barrels are interchangeable with the new Invector barrels which are made in Japan. With this new Invector barrel installed on the Belgian-made Auto-5 receiver, steel shot loads can be used.
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