I'm in the group thinking they may be undersized.
Ed
Agree.
Bullets likely undersized. As a start, you need to slug your barrel to find GROOVE diameter. Then have the bullet 0.001”-0.003” over groove diameter. That will get you closer, but is not really the answer.
Ultimately, you want to know the diameter of your chamber’s THROAT, by doing a “pound cast” of it. Then match bullet diameter to throat diameter ( or just a smidge under, Ex. 0005” smaller). This will be the best way for selection bullet diameter for your barrel.
The pathway of using groove diameter +” a little extra” is a shortcut to the variance you may see in your throat. Do the pound cast method. It’s not difficult. You learn what you need to know, and it allows you to understand your barrel / casting MUCH better. It ultimately saves you time, money and frustration, as you will have an accurate load developed in a shorter time.
https://www.artfulbullet.com/index.php?threads/article-2-how-i-make-pound-casts.131/
