Earlier version Winchester primers were plated, in white boxes until 1999. After 1999 they were unplated and in blue boxes.
Same SKU's (ugh!).
Change was allegedly to increase mechanical sensitivity. (An alleged advantage).
A less charitible person would guess it was a production cost-saving/thruput measure.
For some applications (like firearms with free-floating firing pins such as AR15, M1, M14 pattern rifles), less sensitive primers are an *advantage*.
My guess is that Winchester didn't re-engineer the cups, so the diameter would have been reduced by 2x plating thickness for the newer primers.
I choose not to use the post 1999 Winchester small or large rifle prmers in AR15 or M1 pattern rifles, I'm switching to the CCI primers
(which are still plated) for that usage. BTW, the CCI 450's are designed for higher pressure cartridges like the .223 Rem cartridge,
whereas the CCI400's are designed for lower pressures.
Some notes on primers:
http://www.accurateshooter.com/technical-articles/primers-and-pressure-analysis/
Same SKU's (ugh!).
Change was allegedly to increase mechanical sensitivity. (An alleged advantage).
A less charitible person would guess it was a production cost-saving/thruput measure.
For some applications (like firearms with free-floating firing pins such as AR15, M1, M14 pattern rifles), less sensitive primers are an *advantage*.
My guess is that Winchester didn't re-engineer the cups, so the diameter would have been reduced by 2x plating thickness for the newer primers.
I choose not to use the post 1999 Winchester small or large rifle prmers in AR15 or M1 pattern rifles, I'm switching to the CCI primers
(which are still plated) for that usage. BTW, the CCI 450's are designed for higher pressure cartridges like the .223 Rem cartridge,
whereas the CCI400's are designed for lower pressures.
Some notes on primers:
http://www.accurateshooter.com/technical-articles/primers-and-pressure-analysis/
