Salty, For your OAL question: Close the bolt on yur Ruger and slip a 1/4" wooden dowel down the barrel until it contacts the bolt face and mark the dowel at the muzzle. Next, open the bolt, drop a bullet that you intend to load into the chamber and hold it there with a pencil or cleaning rod and put the dowel back down the bore until it contacts the tip of the bullet. Mark the dowel again. Measure the distance between your marks and seat you bullets so your OAL is .020" less. If these loaded rounds fit into you magazine (Not too long) you're set. If they are too long, you will have to seat them to fit your rifle's magazine. Or, you can just use the OAL suggested in your reloading manual.
Another method is to run a fired case into your sizing die just enough to size about 1/16" of the neck and start a bullet of choice into it (boattails work much better with this method). Gently slide it into your rifle and close the bolt. Measure and reduce by .020". If you don't have calipers, puta sized caseinto your press, run the ram to the top, screw down your seating die until it contacts the case, back off the bullet seating screw, put in your bullet/case combo and run your seating die down until it contacts the bullet. Lower your ram ant turn the seating screw down another 1/4 to 1/2 turn. Again, if this length fits into your magazine, your good to go. If not, keep seating it deeper until it moves freely in your mag.