Rubydak

Reloading 357 with 2400
Standard Vs Magnum Primer Test
8/4/2012 90deg 18% rh

Gun, GP100, 357 magunm.
Powder; 2400
Charge; 12.2gr
Bullet; Speer, 158 gr, metal jacket, *soft point
COL 1.590"
Medium roll crimp.

CCI Primers Standard 500 and 550 magnums

Multipul groups of 6, typical results
*standard primer/magnum primer

AV; 989 / 1042 FPS
SD; 53.9 / 12.9 FPS
ES; 145 / 35 FPS

In this load, the magnum primer adds a about 50 fps and produces much more consistent ammo.

ratgunner

Interesting. Pressures ?

terry_p

The loads are below the range for the Speer manual so it shouldn't show pressure?? Did you accuracy check both? Your results suggest the mag load grouped better?

Pat-inCO

How long is your barrel?
2" = doing OK.
4" = a bit weak.
6" = ADD MORE POWDER.

Rubydak

The magum loads grouped way closer all shot off a rest. My GP100 is a 4" and the loads are light as these are starting loads lighter by 10%. The next batch will be hotter. I'm thinking of using 12.5 gr. Is that too much of an increase?

Any recomendations for the next test?

leroy

I'd recommend 13 grains. I dont think the load is heavy enough to realy get the 2400 goin.

leroy

terry_p

Speer lists 13.8-14.8 gr with a SPP. If I were using the mag primers I would stay in the low end of that range and watch for pressure. Speer has a statement in their #13 manual warning not to use mag primers in that range or you could see high pressure so be warned.

rclark

Interesting. How you setup your test?

When I did the same type of testing for .44Spec and .45 Colt, I used the same set of cases (all had the same number of reloads through them) and same bullet brand. I primed 15 with regular primer and 15 with magnum primer. The same powder throw was used (and each weighed) and the same seat/crimp was done (the seat/crimp die never moved for all 30). That way everything is the same except the primer (close as I could get it). Now, since my chronograph can register 32 shots before being reset, I shot the first 15, and then the next 15 in same session without resetting the chronograph. Environment conditions are obviously the same. FYI, remember you have to have at least 10 shots for ES/SD to be meaningful, more it better. I like 15, because I can 'throw out' the obvious one if necessary and still have valid results.

That is pretty light load. Just keep moving up by 0.5g . You should see some interesting results as you go up.... 2400 likes a bit of pressure. I've tested 2400 with the big-bore (lead SWC bullets only), but not with the .357 yet. I'm interested in your 'results'! 12.5, 13.0, 13.5 .

Also from what I can tell, you should be fine pressure wise if you velocities are under 1300fps with 2400. Note that in my quick look around the web, some are pushing 1400-1600fps for 158g bullet..... Here you have to be start being careful with primer used.... Always work up the load as you are doing looking for pressure signs like sticky extractions.

Rubydak

Thanks all for your input. I did load all these with the crimp die locked down and once fired brass from factory ammo I purchased so all the crimps are the same. I know about the magnum warning but I was getting a lot of unburned powder in the rounds I made the first time. I was doing everything the same except I used 14gr of 2400 and standard primers. I was getting 1150 to 1285 fps and the groups were not good. I had read that this powder can be used to make accurate ammo but I was not happy with my results so hence my testing.

I should also mention that I measure the 2400 with a scale that is accurate to +/- .01grains (1/50th grain accuracy). The typical reloading scale is accurate to +/- .1 (1/5th grain accuracy) so I should be good there.

My current plan is to sneak up on this and watching for any problems. I'll try 12.5 next as these did run light and then I'll try 12.8 next and see how it goes from there.

My goal is to get to 1200 to 1250fps and I'd like to keep the ES to 50fps or less.

rclark

Sounds like you have a plan!

With standard primer (CCI-300) and 2400
In my tests with .44Mag, the ES ranged from 84 to 51 over 16 to 20 grains.
In my tests with .44Spec, the ES ranged from 81 to 35 over 15 to 17 grains.

In .45 Colt I only tested 18g load and ES was 82. Magnum primer ES was 94. Never went any further here.... Going to have to revisit the .45 Colt and get some test data looks like .

You should find the higher the pressure (velocity) the lower your ES with 2400. Was at least in the cases given above.

rclark

Couldn't wait for your test results ... So ran my test today at lunch.

Outside temp 65F and sunny and slight breeze. Hot sitting in the sun!

Ruger .357 BH 6 1/2" Rimrock 158g SWC.

13.0g 2400, 158g SWC, CCI-500, 1235 avg, 16 SD, 48 ES, 14 Shots (of 15)
13.5g 2400, 158g SWC, CCI-500, 1270 avg, 16 SD, 49 ES, 13 Shots (of 15 like)
14.0g 2400, 158g SWC, CCI-500, 1323 avg, 19 SD, 51 ES, 14 Shots (of 15)
14.5g 2400, 158g SWC, CCI-500, 1347 avg, 19 SD, 52 ES, _9 Shots (of 10)

All shot well, but the 13.5g load 'seemed' to be better. It is what I'll load when and if I load some more 2400 loads. The the recoil is very mild (compared to my .45s).

FWIW, Also ran some Bullseye tests too. All these shot well too. Marked all three as 'accurate'.

5.0g Bullseye, 158g SWC, CCI-500, 1018 avg, 10 SD, 42 ES, 15 Shots
5.5g Bullseye, 158g SWC, CCI-500, 1080 avg, 15 SD, 63 ES, 15 Shots
6.0g Bullseye, 158g SWC, CCI-500, 1142 avg, _9 SD, 36 ES, 15 Shots

Tork

rclark,
Thanks for posting the data you gathered. I use Al2400 in some of my 357 mag loads as well. I have a load with a 180 gr cast bullet that I use in my M94AE Winchester that performs well. One feature I like about it over H110 is that it can be loaded down safely. It looks like your having a good time with this. I find the info you share with us interesting.
Cary

Rubydak

Rclark;
Good info on the standard primer data. The object of my testing was to see the difference between using standard vs magum primers as there is published load data that disagree on which primer to use.

Any chance you can run this again with CCI 550 magnum primers?

rclark

I can't promise anything.... But I'll see what I can do in the next few days...

Rubydak

After reading a bit more and reconsidering the data. I made up a batch of bullets to test with 13gr of 2400. 25 each mangum and standard primers. I'll put these through the cronograph next weekend and post the results.