I have a Tikka T3 that I bought new a few years ago. The rifle has always been a tack driver until this summer. I have about 500 rds through it and can not even hold a six inch group at 100 yds. I have copper fouled it, Tried new rings/scope, and checked all the screws for tourque. I think the barrel might be going but the rifling doesnt look bad. Any Ideas? As always any help is greatly appreciated.