Alloy, Pressure

[Frank2]

I used to have load for my BFR .475 revolver of 26.6 grns W296 using the Lee 400.  But later I had to reduce it to 26.0 or even 25.8 because brass would stick.  The new load works OK.  Components are the same.  Could an alloy difference cause the change?  I'm thinking maybe it's the alloy, or it could be the lube. 

[Veral]

  You are thinking exactly right.  Both lube and alloy hardness have a dramatic effect on pressure.
 
  With stout loads, the harder the bullet the lower pressure will be.   Mild or low pressure loads don't show much pressure difference with bullet hardness, nor does it matter.

  No bullet lube made, (that I've heard of) will produce lower pressure than LBT lube.  The  difference in pressure is absolutely dramatic.  For example, if you were to work up a maximum load in your BFR using LBT bullet lube, then switch to any other brand, you'd have cases stuck so tight you'd have to drive them out, and possibly blown primers, or split cylinder throat.  The difference is that dramatic, and in rifles the difference can cause deadly pressure increase!

[Frank2]

That's good to know, Veral.  It was BAC or 50/50 lube.  I used LBT Blue in my 45/70 BFR and it gave the very best accuracy.  The most consistent groups and easiest to work with also.  I'm going to switch to LBT on the Lee 400 next.