Subcal inserts can be very accurate depending on the type - especially the German kinds that lock into the chamber with a free floated barrel and are indexable/adjustable. The kind I'm familiar with are ~12 inch barrel, maybe 8 inch.
Helped prove to me that accurate shooting is far more dependent on accurate sights and stable shooting platform (IE a full stock) than overall barrel length, as a pistol length insert in a 12 gauge will very easily shoots similarly to a rifle in the same caliber, while the equivalent barrel length in a pistol is a challenge. It's all intuitive really, but made me far more willing to trust short barrel rifles.
One thing you could try with the chiappa inserts is a brass sleeve that matches the chamber dimensions. Would need to take care not to dent or burr it, but would give a good snug fit. Could also use a piece of sustarin or the like.
Bookmarks