Recently purchased 40 year old 336 in 3030...had a few minor issues discussed here recently,but all and all gun seems very good internally for its age..here's my question...I read now and then about the possible danger of incorrect head spacing..should I fire the first shots with gun in a vise and 100 feet of string tied to trigger,or should I rush to my nearest smith and have it checked...what do most guys do??...I'm not adverse in just going for it and taking my chances, what are my chances..