Winchester Small Pistol Primers #1-1/2
Country of Origin
United States of America
WLP’s are excellent primers and are no where near the CCI350 as to peak pressure. The CCI350 is a “hot” pistol primer.
John Linebaugh recommends the WLP in the various Linebaugh calibers, as the CCI was found to increase peak pressure by a significant amount in the pressure barrels used in his development testing.
I use the WLP in the 500 S&W as well as the Linebaugh calibers (as well as most other calibers calling for LP primers) and have found the only difference between the WLP and the CCI350 & standard rifle primers is a loss of 25 to 35fps in velocity on the “heavy calibers”.
I thought a hotter primer was needed when using AA1680 powder, as I got inconsistent ignition as well as stuck bullets using the WLP primer in the Linebaugh Max – the AA powder tech advised me 1680 must be compressed when shot from the 500 Smith or Linebaugh calibers and that solved the ignition problem using WLP with 1680.
For the record, I used particularly consistent bullet/powder combinations in 223 and 308 and changed only the primer. I judged primer brissance (not brilliance, BTW) by the resulting average velocities produced. That may not be a fully scientific way, but it seems to make sense from a reloader’s viewpoint. I did not address cup thickness, but the results were as follows, with the “hottest” primer at the top:
WLRM (near tie)
R 9 ½ M
R 9 ½
I don’t know how relevant this info would be today, since Winchester changed the composition of the primer cups on their SR primers fairly recently. Still, I found it interesting at the time as I was doing a lot of work with J-words in .223.