From the Speer #13 printed in 1998.... "We developed new data with Alliant 2400 powder. Changing from Magnum CCI primers to Standard CCI primers
greatly improved it's performance compared to the data in Speer #12. Do not use Magnum primers with Alliant 2400 or Viht N110 loads shown in Speer #13 or high pressures will result."
Now fast forward 10 years to the Lyman 49th manual and I turn to the .357 Magnum load data. I see where ALL their load data with Unique,2400, N110 and the rest of powders used was tested with CCI 550 magnum primers.
Using same Speer 110 gr. JHP bullet...Speer shows 17.5-19.5 gr. of 2400 using a standard Small Pistol primer.
Lyman 49th shows 13.5 - 20.3 of 2400 powder and noted that 20.3 gr. was a compressed charge along with a CCI 550 Magnum primer!
But like I said all of the Lyman 49th .357 Mag loads were with CCI 550 Mag. primers. When I loaded my .357 rounds using some Lyman data I never noted the 550 primers and loaded with Winchester Standard Small Pistol primers. They shot fine of course.
Interesting that Lyman didn't back down their load data when using the hotter Mag primers but increased Max Load!
