Well, my rifle is a vsr type, is a echo1 m28 and the stock barrel is 517mm 6.06 but i found this https://shop.ehobbyasia.com/upgrade...-barrel-for-marui-l96-sniper-rifle-500mm.html maybe will work fine? Btw, it have the stock spring (m140) but really really used! He lose his power by 30 to 40% there's no m140 springs, so i purchase a m130 laylax