Have ever had a rifle that……

[762willdo]

Liked one brass over the other? I have been working with alpha brass in my dasher for a while now and I just can’t get it to shoot as well as I can with Lapua……
I have matched up FPS, weighed every bullet everything I can think of To make every round identical and no joy, Ive done this work at 200yds, the Lapua groups are significantly better, and before anyone ask I even had my wife hand me the rounds so I could eliminate personnel bias…….ideas?
ps. Both groups are good Lapua is just gooder!

 

[mudduck]

Maybe a neck clearance or tension issue?

 

[gunsandgunsmithing]

Equal fps doesn't equal the same pressure curve and exit time. It sounds like it needs a tweak to the load for brass difference.

 

[762willdo]

Sorry I worded that wrong I meant to say my loads are exactly the same within the group?

 

[762willdo]

One difference I realized and can do nothing about is case neck length
alpha is 1.34ish
lapua 1.54ish

 

[Dave Way]

So I would bet if you were to weigh the cases, they are different. You may have adjusted the loads so they are the same velocity wise however the different charges will change the way the barrel vibrates.

Neck tension is likely different because of the different brass. That can have a profound effect on accuracy.

Bottom line is you would need to do a complete load work up with each brand of brass. I bet you would eventually get the Alpha brass to give you the same accuracy.

Dave.

 

[762willdo]

I neck turn my brass and use an expander mandrel so I “think” I have the neck tension issue under control

 

[762plinker]

yep case volume and neck length....work up a load in each.

 

[Hoot]

One difference I realized and can do nothing about is case neck length
alpha is 1.34ish
lapua 1.54ish

That sure seems odd that the necks are so much longer than spec for the Dasher, especially the Lapua.

Hoot

 

[JSH]

So your neck turning, so we will say that is correct and the same.
Neck length may have some influence.
Alloy and spring back may be different. Do you anneal?

 

[762willdo]

Yes

 

[beemanjohn]

Alpha brass has a larger flash hole. That may be it.

 

[10XSHOOTER]

Trim 5 rounds of Lapua brass to same length of Alpha brass. See if that makes a difference