in buying an older rifle are there years to avoid where manufacturing wasnt up to par . or not just years like styles flat back vs round or 110 economy and so on. i am looking to a used 7mm rem mag vs getting just a barrel and switching . i can get 110 for around 300 for rifle or just get barrel and switch ? what to do. i am looking to make a long range hunting rifle . if i make barrel it will be 300 wsm small shank . opinions please thanks