Test of Hercules and Alliant 2400 powder (14 gr each) in the 357 Magnum with a 358156 GC’d cast bullet using 6 different primers.
All measurements were taken during testing conducted on 29 April, 2019. Data recorded with an Oehler M43 PBL using Contender 357 with 7.9” barrel. A 2 ½ power scope was used on the Contender.
Temperature ranged from 80 to 82 degrees.
Humidity was 30%.
Barometric pressure was 29.63.
H2400 = Hercules 2400 manufactured in ’92.
A2400 = Alliant 2400 of current manufacture (purchased 2 months ago)
Velocity in fps is at muzzle.
Velocity SD/ES is fps.
PSI is the pressure (pounds per inch) recorded via the Oehler M43.
PSI SD/ES is the pressure (pounds per inch) variation of the test string.
Group = target at 50 yards with ctc measurement of 2 widest shots.
All test strings were 10 shots.
The 358156 were cast in a Lyman double cavity mould.
Alloy was a soft one made of RL + Pb + tin.
Bullets were AC’d 10+ days before size/lubing and BHN runs 10 – 11.
Bullets as cast are .359+ and were size/lubed in Lyman 450 with .359 H&I die.
Lube used was BAC.
Hornady GCs were seated in the 450 with GC seater prior to size/lubing.
The bullet weight, fully dressed, was 162 gr.
All charges of both the Hercules and Alliant 2400 were 14 gr (+/- 0.1 gr).
All test charges were thrown charges with a Lyman 55.
Charges were verified between each 10 charges thrown on an Ohaus 10-0-5 scale.
Cases were Winchester brass cases.
Cartridges were loaded using RCBS dies on CH press.
Primers are as indicated.
Bullets were seated to 1st crimp groove (the 358156 has two) for an OAL of 1.597”
A heavy rolled crimp was applied.
Looking at just the H2400 data it would appear the old adage of “magnum primers not necessary” does apply. The average velocities between the various primers, standard and magnum, were found to be pretty consistent. The pressures are also consistent and all fall under the SAAMI MAP for the 357 magnum cartridge. However, the accuracy of the magnum primed loads was consistently better than the standard primers with the exception of the WSP primer with the A2400 powder.
Looking at just the A2400 data we see pretty much the same consistence except the Alliant 2400 does appear to be somewhat faster burning than the older lot of Hercules 2400. In my previous testing I was using a lot of Alliant 2400 I purchased about 12 years ago. There was not the difference between that older lot of A2400 and the H2400 that we see here. Note also that this lot of A2400 consistently produced better accuracy than the H2400 regardless of the primer used. Interesting the highest velocity (1607 fps) and highest pressure (41,600 psi) produced the smallest 10 shot group. Additionally with standard primers the CCI 500 and WSP primers produced psi’s right at the SAAMI MAP. The Federal 100 produced a psi 3,400 more than the SAAMI MAP.
Comparing this lot of A2400 to the old lot of H2400 shows a decided difference. This lot of A2400 is obviously faster burning giving 90 to 160 fps (+/-) difference depending on the primer used. The SAAMI MAP for the 357 Magnum is 35,000 psi and we see in Lyman CBH #4 the max load of 2400 with a CCI 550 primer is 14 gr. Looking at the test results the pressure with that load using H2400 is under the SAAMI MAP. But the pressure using this new lot of A2400 with the same load and same primer is 39,000…..well over the SAAMI MAP.
So let’s answer the questions;
“Would it make any difference using these primers with Bullseye, Unique, and Red Dot ?”
Based on the large increase in psi over standard primers in this test it would appear the use of the Federal magnum SP primer would probably increase the psi significantly. If you really want to use those magnum primers then I suggest you drop the charge of any of those powders by 2 gr and work back up the same velocity as produced with a standard primer.
“No Magnum primers with Hercules or Alliant 2400!” ………… “You are probably safe with Hercules 2400, but not Alliant 2400.”
Based on this test it appears neither of those statements are quite correct. The use of a magnum primer and the WSP consistently proved more accurate than the standard primers with the same load. The remaining question seems to be if the load of A2400 is reduced to the SAAMI MAP Using any of the magnum primers will the accuracy be as good? Remains to be seen.
Concealment is not cover.........