Ok I completed my conversion of a rock island armory 1911 .45 to a 40 super. The biggest cost was the barrel it was about $215 for a 5.72 in ported barrel drop in fit that included a barrel busching and link. I also bought a 24 .lbs recoil spring a titanium firing pin and heavy duty spring. The barrel I ordered from storm lake went right in the gun and with the recoil spring the gun was ready to fire I replaced the firing pin and spring to be safe. The first day at the range the pistol fired great no problems as far as a conversion it was very easy and with the 24 lbs. recoil spring it was a joy to fire and recoil was comparable to a standard .45 acp.