.243 Win data

laylandadlaylandad Member Posts: 960 ✭✭
I've worked up to a really good load in the Speer #13 manual using a 90gr Speer spitzer SP with 38.5gr of W760 with CCI 250 primer. I have noticed that cross-referencing data from the powder manufacturer, Speer seems to be a little underloaded. The #13 has a starting load of 37.0 gr of W760 and max of 41.0gr with a magnum primer. Hodgdon website has the starting load at 41.0gr and max of 43.5 with standard LR primer. Who is right? Is it safe to continue to use the Speer data? Is the difference in the data the primer?


  • JustCJustC Member, Moderator Posts: 16,038 ******
    edited November -1
    different test barrels used in the process yields differing chamber pressures
  • MobuckMobuck Member Posts: 11,551 ✭✭✭
    edited November -1
    I've started using a
    Chrony as part of my load workup. When I get the velocity listed I stop regardless of whether I've reached the listed max. If I start getting pressure signs before reaching that velocity, I switch powders. I used to study primers and bolt resistance but I've got too many variables these days. The last 5-6 loads I've worked up achieved listed velocity below the listed max and a couple of those with barrel length shorter than the manual's.
  • laylandadlaylandad Member Posts: 960 ✭✭
    edited November -1
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