New and Fired brass charge adjustment

[19818119]

Gents,

I've recently being running some load development for my .243. As I'm using quickload I measured H20 capacity of new brass vs fired and resized brass.

What I found was that the new cases (lapua) have a H20 capacity of 53gr whilst the fired/resized brass showed a capacity of 54gr.

My chrono verified the quickload prediction that the new brass produces slightly higher velocities (approx 25fps) with the unfired brass.

Do any of you alter your charge weights between your new and fired brass to keep both in the most accurate velocity node?

Thank you.

Rath

 

[Suasponte]

Re: New and Fired brass charge adjustment

No, new brass is just that new brass! Fire form it and load the same load everytime once you hit the sweet spot.

Terry

 

[19818119]

Re: New and Fired brass charge adjustment

Terry,

Obviously once it's FF I'm going to run the same charge. If I can tweak the best possible accuracy from new brass by dropping the charge weight .3gr would that not make sense?

 

[match308]

Re: New and Fired brass charge adjustment

I get about 50-75 fps with once fired brass vs new, and a bit tighter groups.

 

[turbo54]

Re: New and Fired brass charge adjustment

Fundamentally, it seems your question is: should you charge/load virgin cases differently than used cases?

The Zediker book claims you should FF virgin cases using a max charge with the bullet seated ON the lands. He claims this will do the best job of making cases fit the chamber as closely as possible.

If you don't want to bother doing that, I don't blame you - just load them according to the standard load that you normally use for the rifle, and don't sweat the 25-50 fps difference.

 

[19818119]

Re: New and Fired brass charge adjustment

Thanks for the responses.

Rath