Changing Bushings After Annealing

[bill123]

I just annealed my 3x fired 308 Lapua brass with a Bench Source annealer. All signs (tempilaq, flame color changing) were correct and the maker of the Bench Source assures me that I am doing the annealing properly. For argument sake, assume that the brass is annealed properly (not over annealed).

At 100 yards, my un-annealed brass was giving me 3/8" groups. My annealed brass is giving me 3/4" groups. I went back to the un-annealed brass and shot a few groups, just now to see if the 3/4" groups were me or the brass. I got 3/8" groups so I'm assuming it is the brass.

The maker of the Bench Source unit recommended that I try different bushings to see if that brings the groups back down. Has anyone experienced this before and did a smaller or larger bushing work better?

 

[Canadian Bushman]

I believe the thinking here is that by annealing the brass you have reduced neck tension and thrown your load off by just a bit.

Ive seen and heard of this quite a few times so id consider it a common problem.

I think it can be a little more complicated than just neck tension because when we anneal other processes of our reloading tend to have a different effect. I.E. the case springs back from sizing less, and the surface of the brass is "grippy-er", and sometimes we even clean them more to rid the annealed look.

You can try what the guys at benchsource suggested, but you need to also decide how often you plan to anneal as well. I chose to rarely anneal because i dont work my necks very hard and my loads seem more consistent when i dont. Some guys choose to anneal every load, and tune their load to that condition.

 

[MMERSS]

Has anyone experienced this before and did a smaller or larger bushing work better?

Yes.

After annealing I will size my brass .004" under loaded OD then expand with a mandrel 0015" to .002" under OD. If I do not undersize then expand I found my neck tensions when seating bullets feel "all over the place."

 

[Mikecr]

You should have known that changing neck tension would affect your load -before you did it.
What's your plan?
Are you going to run with soft necks or not?
Either way chosen is fine, but you'll need to develop your load with it. Neck tension is that important.

 

[Ol'Gator]

Yeah Bill, why didn't you know before hand. What ya doing asking questions here? A couple of good responses to consider.