Edit as that post appeared when I was typing this: might try to explore powder charges lower than the 72 grains if it was shooting that much better lower. What made you decide to up the charge so much this round?
This reloading stuff is much more harder then I thought.
It can be but if we break it down measuring carefully/constantly and only change one thing at a time it is much more manageable.
What are you loading on/with?
What is the measurement of your fired necks diameter vs your resized necks vs your loaded round?
What is the measurement of your case base to shoulder measurement from new to fired to resized if avaliable. if no new brass then just the fired and how much shorter they get after sizing? You should be using a tool such as this to get them and should only be pushing them back .002 or so. Any more is way over sizing but wouldnt necessarily make groups bad as factory will expand way more usually and can still be accurate. [IMG2=JSON]{"data-align":"none","data-size":"full","height":"415","width":"415","src":"https:\/\/www.grafs.com\/uploads\/product-picture\/preview\/7288.jpg"}[/IMG2]
What is the measurement of your case base to ogive (where the bullet actually meets the lands)? Using the same tool as above but with the bushing for the bullet instead of the case. [IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/www.brownells.com\/UserDocs\/Miscellaneous\/wb1208-Gauging15.jpg"}[/IMG2]
Your bolt closing tough on new reloads when empty brass fit before is that your necks of a loaded round are too wide (doubtful), your headspace isnt bumped back enough (again doubtful) or that you have the bullet too long and are jamming it into the lands on chambering.
I like this method to find out just how far my lands are so I know how much I am jamming the bullet in or how far I am jumping to them.