So, is the consensus for the paper sleeve being a coversion device to shoot 12g in a 10g shotgun? Wheather or not the sleeve is from the manufacturer or home made.
of course it is not manufacturer but home made !
US manufacturers were not dumbs and only stupid people can shoot such a device.
If you still ask yourself such a question it means you have not well understood the harms and dangers for the gun and for the shooter
1st. your right, the primer doesn’t seem to have marks & the case looks nice inside & regardless of the cylindrical marks my 2¢ is unfired & the cardboard sleeves were someones idea of storage protection. Mora’s comment about the red-rouge polishing seems on the mark to me.
2nd the cardboard sleeves would not be used to convert a 12 to fire in a 10. Cardboard compresses & gas leakage due to uneven coverage of the sleeve to the complete shell would likely cause a burst shell. Plus you have an extraction factor with the smaller rim that the cardboard doesn’t fix.
Only caliber converters I’ve ever heard of were either brass, iron, steel or lately made of plastic. Wood was used in early artillery sub-cal devices but the wood only covered the steel chamber / rifled barrel.
I don’t think the sleeve is to protect the shells.
- Because you do that with new shells, not already fired cases like the one showed
- Because the trick to use a paper sleeve is very common (I have seen that many times even with rifles or military ctges)