I've got a R700 in 6.5cm. The rifle has 600ish rounds through it. I have shot hornady American gunner 140gn exclusively. Accuracy has went to shit. It was .75 MOA consistently. It is now 3 MOA. The rifle has hard bolt lift now. I cleaned down to bare met with Hoppe's and Sweet's. I then went out and shot 5 fouled and 3 5 shot groups. Accuracy has not improved. And bolt lift is still stiff. The rifle has been taken down to bare receiver and barrel. Then reassembled with blue lock tite. I have tried different scopes and chassis. The ammo has been tried in a different rifle. I don't have a bore scope to check for a carbon ring. What should I check next? Thank you for your time and help!