When would you use a mag primer in 357 ?

[boatbum101]

Mainly used 2400 for years & Unique for lighter loads . Also for years I used SPM primers either Win or Fed . Recently I started getting ready to load some cast loads up , but now days with tons of data available I'm confused ( or having a senior moment ) . Alliant has come out & said STD SP primers for their powders across the board . Win 296 / H110 & HS-6 have always recommended mag primers . IMR data has said mag primer for 4756 & 800X . 4227 a mag primer . AA#9 I've been told that SD & ES will be reduced by using a mag primer . So whats the ticket in your experience ?

 

[colt_saa]

I am not a 2400 user, but I go through H110 like it is candy. Most of my Unique loading has transitioned to 231 in recent decades. Those three powders account for 75% of my loading.

You use a Magnum primer when you loading manual tells you to.

You can use either primer when your loading manual tells you to use a standard. Just remember that if a magnum primer is substituted it will alter the load.

 

[John R]

I've started just buying all mag primers now, I work up my loads with them and call it good.

 

[mtgianni]

When the load manual says they used a mag primer I use one also.

 

[arjay]

Ill work up with powder first with one particular primer and if the best group is ok but not great,then I'll try that load with different primers.

 

[Nevada Ed]

Only time I use Mag primers is when I load "Ball" type powders
or a powder that is very slow burning or a load ment to be shot
in super cold weather.

Some of my "Winter" hunting loads have a mag primer to insure
I don't get a misfire.......this I learned the hard way on a deer
hunt in two feet of snow on a cold November day.

98% of the time I use regular Winchester, Federal or cci primers
for all my pistol, rifle and shotgun loading.

 

[boatbum101]

Just went & checked latest load data put out by powder mfgers . IMR / Hodgdon / Win state WSPM primer period in 357 as does Accurate Powder . Alliant states Std primers . The one that throws me is Vihtavouri states SR primers in 357 mag . I could see that in 357 max due to cratering / primer flow @ higher pressures , but have never seen it in 357 mag unless gun had an erroded firing pin bushing or extremely hot loads . And with hot loads usually case separation would also happen .

 

[rwsmith]

Is there any powder.....

Is there any powder that using a magnum primer is detrimental??? I'm about to subscribe to the magnum only philosophy and I use a lot of 2400. It seemed like Blue Dot was a little funny about the primers it took.

PS I noticed in the Lyman book that if the name of the cartridge has 'magnum' in it, you use a magnum primer. Other books differentiate a little more in that 2400 doesn't need a mag primer, but the slower powders do.

 

[arjay]

Is there any powder that using a magnum primer is detrimental??? I'm about to subscribe to the magnum only philosophy and I use a lot of 2400. It seemed like Blue Dot was a little funny about the primers it took.

PS I noticed in the Lyman book that if the name of the cartridge has 'magnum' in it, you use a magnum primer. Other books differentiate a little more in that 2400 doesn't need a mag primer, but the slower powders do.

maybe [emoji1].I try to work it so that I have a good selection of either powder or primers to work with a particular bullet.

 

[boatbum101]

Only thing I recall about Blue Dot was it got hinky in cold weather , no 125JHP in 357 & no use in 41mag . N-105 & SR4756 don't like to be crowded also .

 

[jimbo728]

I switched to mag primers with one of my .357 loads after recording lower exteme spreads than I was seeing with a standard small pistol primer. It made a difference objectively so I went with it.
What ever works best.
Every other pistol\revolver load except for that one load I use standard primers. Usually Federals in revolvers and Winchester in the autos.
Jim

 

[mstem]

When is say to in a reloading manual.

 

[Beemer-mark]

SPM

Handloader in issue #99 (1982) did an exhaustive test with magnum loads (44, 357, 41) and concluded that magnum primers greatly increased pressure with no or little corresponding increase in velocity. Recently (within the last 3 years) they did it again with the same results for the 357 magnum. The conclusion was that magnum primers increased pressure to an unacceptable limit. The recommendation was to only use non-magnum primers in 357 magnum loads.

For what it's worth I have always used Federal Match magnum primers and with several thousands on my bench I don't thing I'll be switching soon. However I have made identical loads with both regular and magnum primers after reading the article (168 gn LSWC) and notice no difference in velocity. Standard deviation and extreme spread is reduced with regular primers. When I run out of magnum primers I plan on only using small pistol primers.

 

[bluetopper]

I have used H-110/296 with standard primers and they all performed as they should have.......I will also add, I do know not to download that powder.

 

[fredj338]

IMO, only powders that need a mag primer are h110/w296, maybe lilgun & 4227 if the volumme is high enough.
If you work our loads up, the pressure increase can be negated. The other neg affect can be a reduction in accuracy, more rifle than pistol. Your individual weapon will tell you.

 

[scooter123]

I've seen enough variation on whether a Magnum primer should be used with some powders that I really wonder if it matters. However if a certain load table was developed using a Magnum primer that is what I use for my loads built using that table.

 

[ArchAngelCD]

IMO the only handgun powders which need a magnum primer are hard to ignote slow ball powders like W296/H110, HS-7 and HS-6.

Powders like 2400 and Unique seem to perform much better with a standard primer over a magnum primer. After all, they were developed and used for a very long time with standard primers since there were no such thing as a magnum primer back then.

 

[muddocktor]

I've pretty much used mag primers in any and all 357 Mag rounds I load. I just adjust if necessary if the load out of the book shows using standard primers instead of mag primers. And rwsmith, I use CCI 550 primers in 357 with Blue Dot with no problems that I have noted. And while I no longer load BD in 125 grain loads, I used to back a long time ago and I never noted any problems. As for BD getting hinky in cold weather, down here in south Louisiana we hardly get weather cold enough to affect loads significantly.

 

[jculloden]

I've been using Federal Match small rifle primers in pistol for years, works for me

 

[alwslate]

I basically use magnum SP primers or SR primers in all my 357 loads
now. That is a decision I made after much reading of loading manuals
and running comparison tests of loads with std and mag primers with
a chronograph. In the long 357 case I find that mag primers reduce ES
with all loads from midrange with fast powders to heavier loads with
slow burners like 2400 and 296.