Product Update! The forthcoming 2" Outer Barrel Extension will now also include a BONUS inner barrel stabilizer o-ring.
The rubber o-ring IMPROVES ACCURACY by wedging between the inner barrel and outer barrel extension, reducing inner barrel vibration during shooting. Note: designed & tested for Madbull brand inner barrels.
Pretty clever, right?
More info: http://madbull.com/catalog/index.php?main_page=product_info&;;cPath=5&products_id=418