How do Lapua cases differ internally from Remington cases?

[RedRyder]

In the past, I used Remington 260 cases but I just started reloading using Lapua 260 cases. My groups have opened up considerably. I'm guesstimating that there may be a volume or capacity difference between the two case types. I'm also guesstimating that I should use more 4350.

Is there a difference in capacity between Rem and Lapua?
Do you think I should increase the load? Currently 42.0g I4350

thanks in advance

 

[Fursniper]

Yes, there is a difference in case capacity. Lapua brass is thicker & stronger. Necks are thicker too & the cases have a much stronger Web area. You could increase your load slowly, carefully watching for pressure signs. I run 42.4 grs in my 260 with velocity at 2830.

 

[roggom]

This is where software like Quickload shine. You have a given load, then you can replicate it with different brass by measuring water capacity of the case. Or you can just drop down a bit of powder and work back up.

In short, you can not use the same load in two different headstamp brass and expect the same results.

For me RP with 139 scenars is at 42.4 IMR 4350, with prime brass its 42.6, Lapua its 42.8 . Not much, but enough to effect groups

 

[Supersubes]

You can test the water weights yourself to see what the capacity difference is. My experience with rem brass is that its incredible soft. The lapua is far stronger. It's also more consistent case to case and lot to lot. If you're expereincing accuracy issues, id chalk that up to something else, like greater neck tension from the thicker necks, or the smaller capacity/higher pressures busted you out of your node. You just have to find what it is. Is this a custom rifle, or factory?

 

[RedRyder]

It's a custom gun. Beanland.