guys hunting the pines up north have been using .12ga with slugs for years as thats all thats allowed,SiB your .12ga is running at low pressure the insulation tape over the end is far less obsticle than the crimp on the shell and the choke will create more pressure than a thin wee bit of rubbery plastic ever will. having had shotgun barrel split/burst from being plugged with clay....tape the hua and be done with it.
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