There's no way you can come out ok on that deal from Ruger. Your Security-Six works ok. Enjoy it. About the blow back being more on one chamber. If you have a gun smith use a forcing cone cutter to gently alter the angle where the bullet enters the barrel--the forcing cone, that procedure will correct the blow back. If you call around to gun shops, you will find someone who does this. Time required is about 15 minutes. Shop for a good price. Many hobbyist have this tool. About the grittiness. If Ruger did still service these guns, they would tell you that this is normal--unless you were paying them to improve it.