westernrover
Member
- Joined
- May 4, 2018
- Messages
- 1,613
Good question, there’s a key phrase from an earlier post that people sometimes overlook. Chambering freely is the goal so from just smooth bolt closer we bump .002, a lot of guys just bump a fully formed case but we find out that sometimes that’s just not enough for smooth cycling.View attachment 1042117
Why is chambering freely the goal? An inability to close the bolt would be something to avoid, but what is it about smooth cycling that indicates a better fit than a little resistance?
Firing once may not represent the actual dimension of the chamber, so bumping 1-2thou from fired brass may be sizing too much or too little.
Bolt close method can’t lie. The case either fits or it doesn’t, and when it has been sized just to the point of kissing the shoulder, we know a true dimension of the chamber.
Basically, it’s like measuring my sock versus my foot.
I can see how sizing 1 to 2 thou under the dimension of a once-fired case could be needlessly sizing the case down, and the bolt close method would disclose whether the case really needs to be sized down that much or not. Bumping a fired case seems less and less likely to size the case down excessively on subsequent firings. Even so, I can see how the bolt-close method could be used without the necessity of more firings and that it demonstrates a more direct feedback.