Is a Magnum Primer OK in a 38 spl load?

[duck911]

First, I have used the trusty search function but I feel the jury is still out.

I *finally* located a 1000 Federal Small Pistol Primers and picked them up even though they were Magnum primers (I figured I could always use them in .357 Mag loads...)

My intended use is 38 spl loads using Trail Boss to push a 125 gr LRNFP about as slow as it can go for a fun plinking load.

I've read:

Don't use Magnum primers with Trail Boss
Don't substitute Magnum primers for standard in a .38 spl (across the board)
Magnum primers should only ever be used in Magnum calibers

Or......

Reduce load, substitute Magnum primer, and work back up
Magnum primers are a fine substitute for standard primers
"I've shot Magnum primers from 38 spl for years"

Like I said, my intent is a very reduced load in the .38 spl.

The Trail Boss website states:

Bullet: 125 GR. LRNFP

Minimum load:
3.0 gr Trail Boss
753 FPS
11,600 CUP

Max Load:
5.3 gr Trail Boss
952 FPS
13,400 CUP


Now for the question:

Is a minimum load of 3 gr of Trail Boss using a MAGNUM PRIMER safe?

thanks,

--Duck911

 

[Matt3357]

Well, I can't say for sure about trail boss, but I've been shooting Winchester magnum primers in my 38spl plinking loads and nothing bad has happened yet with zero signs of powder with a medium load using AA#5 and Unique. Seems to go bang every time I pull the trigger so I don't see why it would hurt. I will be interested to see what people say.

Thanks,
Matt

 

[JDGray]

Just reduce your powder charge, you'll be fine

 

[duck911]

A few more data points:

The 38 SPL load will be fired in a modern .357 revolver.

Also, IMR's website claims that the Trail Boss .357 load does use a magnum pistol primer.

So if I am loading at the bare minimum for .38 SPL, using less powder than the accompanying .357 load (and using the same, Magnum primer), I am not sure how this could possibly be unsafe?

--Duck911

 

[NCsmitty]

This data is from the Chuckhawk site.

I'd say try the 3gr load with the Mag pistol primers. The fact that you're using a 357 Mag firearm, I would think it should be safe.

.38 Special

STARTING LOAD - Case: Win. / Primer: WSP / Barrel: 7.7" / Bullet: .357", 158 grain LSWC / Powder: 2.7 grains Trail Boss / MV 661 fps / MAP: 11,400 PSI.

MAXIMUM LOAD - Case: Win. / Primer: WSP / Barrel: 7.7" / Bullet: .357", 158 grain LSWC / Powder: 4.2 grains Trail Boss / MV 804 fps / MAP: 13,700 PSI

NCsmitty

 

[JDGray]

I should have said, the magnum primer will take the place of some powder, can't see a problem in your case.

 

[SASS#23149]

having shot hundreds of .38 midrange loads with magnum primers,I"m sure you're safe.
as to light loads of TB,it's a very wimpy shooting powder,so I'd start in the middle unless ya just gotta have zero recoil...........and what fun is zero recoil ??

 

[Landric]

I had a thread about this going a little while ago:

http://www.thehighroad.org/showthread.php?t=450438&highlight=Experience+Small

I've got some .38 Specials loaded up with 125 grain lead bullets, Trail Boss, and magnum primers. I'm going to be shooting some of them tomorrow. I probably won't have time to set up the chronograph, but if I do, I'll post the results.

My finding so far with the loads I have tested is that magnum primers don't make much difference, with the exception of a lot of the loads being more consistent. I saw about 50fps average velocity increase with 9x19 FMJ and .32H&R Magnum, but no real change with my other test loads. No signs of high pressure with any of them.

 

[ArchAngelCD]

duck911,
Here are a few facts. (and I do mean facts)

1. Magnum primers should be used with any powder which is hard to ignite regardless of whether or not the caliber is called Magnum. (W296, H110, HS-6 and a few others)

2. Magnum primers aren't some magic pill that will blow your gun up if you don't watch them closely. They burn slightly hotter and slightly longer than standard primers, that's all..

3. If all you can get is Magnum primers use Magnum primers. You will see very little pressure/velocity change with 3.0gr TrailBoss when you use a standard primer or a Magnum primer.

4. The same holds true for rifle calibers. Use a Magnum primer with hard to ignite powders but add 2 more reasons. You might need a Magnum primer in VERY cold weather. You should probably use a Magnum primer when the charge is 80gr or higher regardless of which powder you're using. (some reloaders use a higher or lower charge weight as their cutoff) With that much powder you want to be sure you get it all burning and a Magnum primer will help that along.

I hope this helps a little and will ease your mind about using Magnum primers in a .38 Special. When things get back to mormal you probably will have no reason to use a Magnum primer in that caliber but for now, use what you can get or don't shoot. (which is totally unacceptable of course)

 

[JimmyN]

I'm using Trail Boss and magnum primers in both .38 and .357 cases.

Hodgdons online load data for Trail Boss shows the same max loads for both .38 and .357. The only difference is the .357 load specifies a magnum primer, rather than standard. Pressure for their 4.2gr max magnum load is only 20,400 with a 158gr LSWC.

I usually load my target/plinking rounds using .357 cases, so I don't get the buildup in the cylinders. Right now my favorite and most accurate powder puff load uses Trail Boss and a magnum primer:

Starline .357 magnum brass
158gr LSWC
2.9gr of Trail Boss
Winchester SPM primer

I've shot the same load, but using a .38 case with a magnum primer, and couldn't tell any difference in recoil or accuracy, I just prefer the longer cases so I don't have to clean carbon rings out of the cylinders.

 

[jjohnson]

Okay on my end

I'll stop just short of making it a recommendation.

Since primers are just a wee bit scarce just now I've loaded up a couple thousand of .38 with Small Magnum Pistol primers.

No problems, no signs of excessive pressure. While that doesn't mean it's safe, I'm not sweating it - because I, too, am loading in the middle of the powder charge range AND most of 'em are shot in .357 Magnum handguns or my '92 Puma carbine.

I do load 'plinking/practice' rounds for my one .38 snubgun on the light end of the powder charge scale, and I've loaded some of those with magnum primers, too. Again, no signs of anything amiss. It may even be a good idea for the snubbie, since the short barrel means that with some powders, lots of it's left unburned by the time the bullet leaves the barrel.

Of course, "your results may vary."

 

[fecmech]

Not exactly mag versus standard but standard small pistol vs small rifle primers. Since I could not get any small pistol primers I bought 3 K small rifle primers. As you can see not much difference for a 10 shot string out of my .357 rifle. Load was 38 spl case 158 rn. lead.

5.1 Unique/Small Rifle Prime
High--1124
Low--1036
ES----- 88
SD-------25
Avg 1079

5.1 Unique/SP

HI 1091
Low1047
ES----44
SD---- 12
Avg 1066

BTW the rifle primed loads are slightly more accurate!

 

[Kernel]

Use the mag primers. You're no where near to pushing the envelope.

 

[Landric]

I just got back from the range. I loaded up a bunch of .38 Special using 125 grain cast RN, Winchester Small Pistol Magnum primers, and 4.0 grains of Trail Boss (Hodgdon's website shows 3.0 to 5.3 grains), and mixed .38 Special brass. We fired almost 250 rounds of this load in a couple of lightweight revolvers (a Taurus 85 Ultra Lite and a S&W 37-2 Airweight) and a 2 1/4" Ruger SP101.

First off, no signs of high pressure, recoil was very mild, almost non-existent in the SP101, and it actually made the lightweight guns a pleasure to shoot. The rounds shot point of aim, and we experienced no other problems.

I chronographed some, velocity ran 674fps to 744 fps, with all but one round (the 674) between 730fps and 744fps.

I'm comfortable using magnum primers for .38 Special based on this and other experience. YMMV.

 

[duck911]

thanks guys! This is some great info. It seems to me like the Mag primers may be OK to use, starting low and working up carefully.

I have about 20 .357 cases and will start with those just to make sure the Trail Boss likes the Mag primers (in my gun) and go from there.

thanks for the info,

--Duck911

 

[Six]

Stupid question from a reloading newbie...but is there no hard data for this often asked question?

Has no one loaded up batches with magnum/standard primers and measured the pressure and velocity and published the numbers?

 

[Landric]

I don't have any way to measure pressure, but if you look at the link I posted above (#8) it has results in several calibers using standard and magnum primers with all other components the same.

 

[CSA 357]

Should be fine, in a light load i see no reason not to use them

 

[ArchAngelCD]

thanks guys! This is some great info. It seems to me like the Mag primers may be OK to use, starting low and working up carefully.

duck911,
While starting low and working your way up is always a good practice you will need to take no more care with the Magnum primers that you would with any other new load you are working on, really...