new to this forum, not overly educated, however i have built a couple of side by side rifles on shotgun actions. both were 30-30 winchester, one a stevens mod 365 16 ga. and the other a remington mod 1894 16 ga. in both cases i sleeved barrels into the existing shotgun barrels. 25" bbl length. i fitted the inserts at the muzzle with an ecentric bushing, additionally i fitted one inch collar over the insert that i could slide back and forth between the chamber and ecentric bushing fitted with a set screw to secure the collar. one rifle was scoped the other open sighted. the ecentric collar helped much in regulating the barrels however at 75 yards you get to a point they simply would not come together. i had read an article in the double gun journal a few years ago about a gentlemen who added the collar and everything worked. once i added the collar each rifle came into their own. each gun equally at 75 yards will consistently shoot both barrel's to point of aim and into 2.5" groups. the only other work i did was bushed the firing pins and modified the extraxtors. this still turned out to be a lot of work but its a poor mans double and here in georgia all i hunt is deer. i chose the 30-30 simply beacuse in factory loading its low pressue and rimmed. the inserts were turned pretty thin between the chamber and muzzle but after 400 rounnds in each gun they haven't become self openers yet. any comments would be appreciated. i plan to began another project next month in 30-40 Krag. Great Forum