Dave:

Good info, I have a 1911 and can test it. With the 7.5 LW I have one of each of the groups (K-31, K11 and the 7.5 LW (its Loather Walther barrel what chamber do they do that in?)

I have the chamber gauge but assume its European spec (CIP?) whatever that really is.

I do run separate groups of brass in each one.

I just do a minimum shoulder bump back for re-size, shooing for .004 (ideally .002 but with the case variation I get some too long so I go for .004)

Still why the major difference in the shoulder being so short vs the chamber? As that is GP-11 and new brass that is a standard.

The 7.5 can be set headspace wise to whatever I want as its on a Savage receiver and the barrel can be screwed in a more. But that would mean a guess or using a new piece of brass as that is less than the headspace gauge by a fair amount.

Werid stuff.

Have to see if I have some new 30-06 brass to look at old cartridge and see how it comes out. Some reports are that the US looked at GP-11 bullets latter as well as Mauser 8mm basic design when they did the 06.

What is odd is that they went with a more slopped shoulder. The GP-11 is clearly a more efficient cartridge. Its clocking 2550 or so with around 50 grains of powder (R17).

I have taken apart 4 bullets now and clearly they are adjusting powder to strength of powder batches to maintains a velocity as it ranges from 49.4 to 50.5