Logically, there can only be two causes of your problem. First, it can be your rifle. If it is a factory Ruger rifle you can rule out a short rifle chamber because all factory built rifles are test fired before leaving the factory. The other rifle related item could be a bolt problem. You will have to disasseble the firing pin assembly from the bolt shroud. Do not remove the firing pin spring. Inspect all parts of the bolt (interior and exterior) looking for broken or sheared parts or areas. Clean the firing pin assembly and the inside of the bolt shroud with non chlorinated brake cleaner. Re-lube the assembly and shroud with silicone spray. Do not oil or grease. Put a dab or grease on the inside of the bolt lugs only to prevent your lugs from gaulling. Do this everytime your clean your rifle. The last rifle related issue could be a large carbon build up in the throat area of the barrel. You would need to bore scope the barrel to determine if that is the problem. If there is a large carbon build up it can cause the case neck to be difficult to chamber and extract. To remove a heavy carbon build-up is nothing short of serious heartburn. There are many posts concening resolving this issue. If these two items do not correct the problem you will have to look to the brass cases. First measure the overall length of your cases. They should not exceed 2.200 and should be trimmed to 2.195. With a Swift the length must be checked after every firing. Next, the extractor groove should measure appoximately .442 . The case base (rim) should measure approximately .468. The case web (area just above the extractor groove) should measure approximately .446 1/2. (these measurements are based on Winchester brass but all brands should be close). If all of this checks out you will have to get a new unfired case and buy a .264 neck die bushing (Wilson or Redding). Slip the bushing over the neck of the case and measure from the top of the bushing to the face of the case base. This will give you a arbitrary datum line. Measure your brass and compare the measurement to the new case measurement. If your brass measures less you are setting your shoulders back too far with your sizing die. If your brass measures more you are not setting your shoulders back enough when you are sizing your brass. You should be setting your shoulders back .002 to .003 from a measurement taken from a fired case that was fired in your rifle. Shoulders for a Swift should be bumped after every firing with either a F/L die or a shoulder bump die. My best guess is you either have a bolt problem, over length brass or a throat carbon problem. Good luck solving your problem.
