hoppdoc

Ideally the distance between groups should be the distance between the centerline of the barrels.

If your barrels are close, as in a large cartridge, it could be as little as half an inch. If a small caliber it could be one inch or more.

Theoretically it should stay that way to Infinity, and Beyond.

An open sighted Double should be as accurate as any open sighted single barrel in the same cartridge.