357 Magnum & 2400: Standard or Magnum Primer

[Shrinkmd]

I see this topic discussed here and there, so I thought a poll would be in order.

When loading 357 magnum with 2400 powder, do you use the standard or magnum primer? And what differences have you seen?

Both the Lyman and Hornady manual list Winchester small pistol magnum primer with their data. Would I be safe starting out with some Federal SP primers and using the lowest charge for 2400 and working up? I plan on shooting 158 LSWC (Dardas cast) and 125 JHP (Montana Gold)

Thanks

 

[bullseye308]

I have loaded 357 magnum with 2400 and standard primers using my own cast 158 SWC from wheel weights in loads up to the top end with no problems. I have not tried magnum primers so I cannot comment on them.

 

[freakshow10mm]

Try both, work both up at the same time, choose the better one. #2400 is funny because it's about the same burn rate as Blue Dot and #9 both of which a lot of data use magnum primers. As a general rule in handguns I use a magnum primer any time the charge is 10gr or more.

 

[rcmodel]

I have seen notables such as Elmer Keith & Bryan Pierce both say standard primers give better accuracy and less pressure variation when using 2400.

I don't know for sure, because all I ever used in the last 47 years of loading 2400 in Magnum revolvers has been standard primers.

It also might be worth noting that when the .357 S&W Magnum came out in 1935, 2400 was the standard powder used in factory loads.
With standard primers.

Magnum primers were not invented until some 30 years later with the advent of harder to light ball / spherical pistol powder.

rc

 

[CTSigLover]

I have seen notables such as Elmer Keith & Bryan Pierce both say standard primers give better accuracy and less pressure variation when using 2400.

That has been my experience exactly.

My default position is always to start with a standard primer, moving to a magnum primer only when necessary for any particular load, and I have never needed it with 2400.

That being said, I do use magnum primers with 296 and 'Lil Gun, but not with 2400.

 

[USSR]

I have seen notables such as Elmer Keith & Bryan Pierce both say standard primers give better accuracy and less pressure variation when using 2400.

+2. That's all I use behind my load of 2400 and cast 358429's.

Don

 

[Gryffydd]

I haven't found a use for magnum pistol primers other than W296/H110 so far. (Doesn't necessarily say much)

I had excellent luck with 2400 with standard primers.

 

[Randall]

standard primers work fine,I have used mag primers when out of standard and could tell no difference.

 

[MMCSRET]

I've been loading that combination for over 40 years and have never found need for a magnum primer.

 

[Steve C]

2400's pressure increases significantly when using magnum primers. I've had cratered and pierced magnum primers with 158gr .357 mag loads using 2400 that are under 14.0 grs. while maximum book loads say you can go up to 15 grs. Switching to standard primers produced more velocity with no pressure signs up to maximum loads.

Typically I only load 14.0grs of 2400 with standard primer behind a 158gr jacketed bullet as it duplicates factory velocity of better than 1,240 fps from my 4" revolvers.

 

[Shrinkmd]

Thank you for all the replies and experience. It is great when someone posts that they have 20 or 30 years of doing something a certain way safely, and that they can share that info with others.

Well, once I get the dies readjusted, I will make up my first batch of mixed case 357, 125 gr Montana Gold JHP.

Lyman says 13 to start, but Hornady says 13.9. What do people recommend to start? I will be shooting in 2" steel snub and 686 4"

 

[ArchAngelCD]

I've found 2400 prefers standard primers. I get lower SD numbers with a standard primer over a Magnum primer. Also, most "old timer gun writers" swear by standard primers with 2400.

 

[rcmodel]

Lyman says 13 to start, but Hornady says 13.9. What do people recommend to start?

Alliant load manual says 17.5 grains 2400 with a 125 GDHP.

Reduce 10% and you got a 15.7 starting load.

I would not be at all surprised if you like that so well you stay with it.

rc

 

[Slamfire]

I have used WSP for decades with 2400 and the 357. No problems.

 

[Ben Shepherd]

I'm in the minority here, I use magnum only with 2400.

I note a couple things however:

1. Most if not all current manuals recommend standard primers citing less variation in velocity and pressure.

2. Other reloaders, some with much more experience than myself report those same results over their chronos, as do I.

Why do I use magnum primers only then? -
Because in three different calibers in sub freezing temps, I got squib loads with 2400 and standard primers. This has NEVER occurred with the magnum primers and 2400. So I live with the slightly more erratic characteristics of the magnum primer/2400 combo while having assured ignition in ALL weather conditions.

Of course, each load is worked up carefully for each gun, and tested in weather from sub-freezing to above 90 before I consider it proven. YMMV, etc.

 

[LTR shooter]

When loading 357 magnum with 2400 powder, do you use the standard or magnum primer? And what differences have you seen?

With this particular load the difference was a tighter cluster of shots with the use of magnum primers. I have accuracy tested this particular revolver with many powders and bullets over the years and the spread delivered with the std primer and 2400 is not typical of the usual performance turned in by this 686.

 

[Oldtrader3]

Since 2400 is not a ball powder, you probably do not need to use a mgnum primer. If you are going to load Lil gun or H110, then use a magnum primer.

 

[243winxb]

Correct primers for 38 and 357
Reloading data lists these primers to be used with the 357 magnum. CCI 550 Mag., WSPM, FED 200, REM 5 1/2 Reloading data lists these primers to be used with the 38 special and 38special +P. CCI 500,Rem 1 1/2, Fed 100, WSP, Speer list the CCI 550Mag primer for Alliant 2400. This info is available at all primer manufacture websites.http://www.thehighroad.org/showthread.php?t=382053

 

[rcmodel]

LTRShooter
I would offer that your results on the target you posted may be caused by the very light loads you are shooting.

12.5 2400 & a 158 XTP is very likely not developing enough pressure to get a good burn going with the standard primers.

2400, like all magnum class powders, needs high pressure to light & burn right.

rc

rc

 

[Oldtrader3]

There is no hard and fast "rule" for the use of magnum or standard small pistol primers in loading the .357 magnum. Almost no .357 loads burn more than 20 grains of powder. Some magnum pistol powders require a hotter primer for cleaner burning. These powders incude: H110, H4227, and Lil Gun, plus maybe Win 231 powder. Red Dot, through Blue Dot, 2400, Unigue, Bullseye et al do not require a magnum primer because they are not heavily deterent coated powders, are easier to light and use less powder for .357 loads than the ball/spherical powders mentioned. Look in the Speer and Hodgdon reloading manuals. The small pistol magnum primers used are only for ball/spherical powders like H110, H4227 and Lil Gun.

 

[ArchAngelCD]

I'll add HS-6 to that list of powders that you should use a Magnum primer with.

 

[MovedWest]

It depends on the load. If you have a hotter load you can try both primers and see which one performs better for you. If you have a light load you might want to go with magnum primers to get the fire stoked with 2400. The 2400 powder charges seem to like higher pressure rounds, so extra fire or a different powder would be a better choice with lighter rounds.

-MW

 

[LTR shooter]

LTRShooter
I would offer that your results on the target you posted may be caused by the very light loads you are shooting.

12.5 2400 & a 158 XTP is very likely not developing enough pressure to get a good burn going with the standard primers.

According to the 4th and 6th Edition Hornady manuals I use that particular load is right in the middle of the load range specified.

4th Edition: 11.5 - 13.5
6th Edition: 10.5 - 14.3

4th Edition stated Federal 200 primers for the 357 loads.

6th Edition stated Winchester WSPM primers.

Now when using VV N-110 and the 357 mag for some of my TC loads I have used small rifle primers as specified by some earlier VV data. The accuracy was excellent.

 

[Rollis R. Karvellis]

I have found that burning large coluem's of 2400 a good magnum primer work's best, at lest for me.