Double feeds generally have one of two causes, or a combination of both; bad mag, or bad disconnector. I would label your mags, a piece of tape on the base with numbers is fine for testing,then test fire. If you only have one mag, get another one, then test. If you have malfunctions with only one mag and not the other, get rid of it. If it happens using both mags, on to the trigger group. Disassemble/reassemble as mentioned by F-111 John, test with both mags; If it still malfunctions, you have two choices; Send it to Ruger, or put a different trigger group in. I recommend the BX25, as mentioned, it is an upgrade and should solve your problem. I still recommend the hold-open and extended mag release I mentioned earlier. I hope your friend can fix it for you.