I've owned this rifle for about 2 years. Chambered in .45 Colt. It is a great shooter and is accurate as I am. I am having issues with the hammer not always locking back when I work the lever. Works perfect when just testing. The rifle has done this from the time it was new. Sometimes it works, sometimes it doesn't. Do I need to remove the stock and do a deep cleaning, or is something else going on? I use it in cowboy action shooting.