SmallCaliberCentral

Is it necessary to "break in" a centerfire prior to beginning load testing?

Shilen says after inital ten shots and cleaning after every round then clean every five rounds. At this time it is a goood time to test load workup!

When I started loading for my .204, I had a bunch of Winchester 748 powder on hand for my ARs and started out using it....I do get a difference in accuracy between standard and magnum small rifle primers in my .204s...

When working up loads, I will find the bullet manufacturer's published max load and drop down one full grain and build a series of ten rounds each in .1gr increments with the bullets seated the same length, normally their listed max and find the best group....generally it will be .4-.7gr below published max load....

If, for some reason, there isn't a really good group out of the bunch, then I will start tweaking the seating depth...based on the best that showed up...While it's an older target, the one below was my first attempt with my AR and over the years, it's proven to be consistent, so I don't change a thing...

Nice group , I have win 748 as I started with it loading my 308 It is interesting how various burn rate powders group. Even some I would not think would. I am going to try some 748 load workups when the sping warmth hits. As of now I am seeing same hole groups with 10 x, But perhaps 748 could be more consistant. We Have only a bit of time to try! Nice Shooting Thanks