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Old April 23, 2011, 05:51 PM   #1
mehavey
Senior Member
 
Join Date: June 17, 2010
Location: Virginia
Posts: 5,515
Powder Lot Change Effects

Having figured out where the Model-70 wants bullet standoff to be using the 175SMK last week, I also picked up another (several pounds) of IMR4831.

Just for grins, I ran a Lot# Change series today (weighing the cases this time)to see if velocity differences would be noticeable. (The lots were only several months apart)

Last Week @74DegrF:
Lot#255 (my old Lot of IMR4831) gave me 2,530fps last week using 53.3gr

This Week @73DegrF
Lot#255 gave me 2,527fps
Lot#265 (New Lot) produced 2,457fps (with unsually good StdDev)


Quite a difference for those who operate at/near MAX loads.
Be forewarned (again) to step things down before you step them back up.
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