I have started loading up some test rounds in .44 Magnum using the Speer 4453 JHP bullet.
Looking at data using Unique powder the Speer 13th book list the COL at 1.575 which puts the
end of case right in middle of the crimp groove allowing a nice crimp.
The load range is shown as 9.2 - 10.3 Max.
In my 49th Lyman book the same bullet is listed as 1.610 COL and the load data for Unique
is listed as 10.8-12.0 Max.
At a 1.610 length the bullet is right at the lower edge of the crimp groove where it is not as deep.
You definitely get a better looking crimp when the bullet is seated in the 1.575-1.585 range which is where I seat them.
I am loading them to 9.8-10.0 of Unique and shooting for 1000-1100 FPS. out of a 4.25-7.5 barrel length revolvers.
So I assume from this that a .030 difference can require that much of a load difference?
The Speer book doesn't state pressure where the Lyman book does which is 30,500 to 38,700 using their higher load but longer COL of 1.610.
Looking at data using Unique powder the Speer 13th book list the COL at 1.575 which puts the
end of case right in middle of the crimp groove allowing a nice crimp.
The load range is shown as 9.2 - 10.3 Max.
In my 49th Lyman book the same bullet is listed as 1.610 COL and the load data for Unique
is listed as 10.8-12.0 Max.
At a 1.610 length the bullet is right at the lower edge of the crimp groove where it is not as deep.
You definitely get a better looking crimp when the bullet is seated in the 1.575-1.585 range which is where I seat them.
I am loading them to 9.8-10.0 of Unique and shooting for 1000-1100 FPS. out of a 4.25-7.5 barrel length revolvers.
So I assume from this that a .030 difference can require that much of a load difference?
The Speer book doesn't state pressure where the Lyman book does which is 30,500 to 38,700 using their higher load but longer COL of 1.610.