357 mag , Magnum primers or not needed ?

M

Metal god

New member
Hey guys and gals ,

With all this new found free time on my hands I've been doing some reloading . I was looking at my notes and some loads I worked up a year or two ago but don't load much . What I see is that I was using mag primers with powders that likely don't need them . Powders like CFE pistol , W-231 .

That got me think how I don't use magnum primers in any of the other cartridges I use those powders in so how important is using them when loading 357 magnum while using traditionally none magnum type powders ??

This also brings up the idea of 2400 not needing magnum primers even for heavy magnum loads . I've read you will get much higher pressures if you do which leads me to think I'd get much lower pressure if I didn't use magnum primers loading 357 and powders like WSF , W-231 , CFE pistol .

Oh then there's powders like HS-6 which I've heard may actually do better with magnum primers even though it's often not required in cartridges HS-6 is often used in ?? I bring up the HS-6 thing because I do have a 158gr hard cast lead load using HS-6 and magnum primers . I think it's 9gr or so and it feels hot to me and smokes like I'm shooting black powder , ok maybe not that bad but it's by far the most smokey load of any cartridge I load .

Any thoughts ;)
 
One thing I have discovered with reloading. If it works for you, and it is safely within the parameters of tested and published loads......go for it. I have read articles and threads about primers for years. The info doesn't change much....at least for the most part. Those in the know, tell us some powders need a magnum primer for proper ignition, and some don't. Some folks find that the use of magnum primers with those powders that don;t, still perform better with them. While I see many load books showing the use of magnum primers with 2400, I have read many articles from those in the know, that say do NOT use magnum primers with it. As experienced as I am, I still go with what the experts tell me is safe....then I determine performance from there.
 
2400 does not need magnum primers -- but they don't hurt anything either. You can also use small rifle primers in pistol cartridges; when I first started reloading I used Federal 205 primers in everything.

That's not to say primers are totally interchangeable. Use the primers you have, and work up your loads using them. A very few powders require (or at least appreciate) a mangum or rifle powder. 296 is one of them. HS-6 might be another.
 
Be careful using extreme preprimed brass with unknown primers in them, i bought 500 of these and loaded 125g bullets with light loads of H110, at the range i was pounding bullets out the barrel of my nice ruger gp100 357mag because the powder didnt ignite, that was a bad day.
 
H110/296 is known for squibbing out if the load doesn't fill the powder space under the bullet 90% or better and if you don't use a magnum primer. For powders like 2400, try both, working up from a starting load separately. You may find you need 5% less powder with a magnum primer but for funny reasons, the magnum primer can occasionally produce lower velocity. Either way, look at velocity SD and see which primer produces lower SD (as a percent of muzzle velocity) as that generally indicates more consistent ignition. If they are the same, save money by using the standard primers.
 
Am I wrong in thinking I can simply try the standard primers in loads I've already worked up using magnum primers with out starting over ?
 
I have some experience here (CCI 500 / 550):

With HS-6, I consider a magnum primer to be essential. With standard primers, my chrono results showed less consistency. Burns were likely less clean too (subjective observation). I have extensive experience with HS-6. Bottom like is that it NEEDS a magnum primer and heavy bullet to reach top performance.

My only experience with W231 with magnum primers was during the shortage. I ran out of standard primers and used mags for my target ammo. I didn't even chronograph them. They performed with no difference that I could tell. (I loaded them with my standard primer data, without change. These were low-pressure lead target rounds.)

I ran extensive chronograph testing with 2400 using standard and mag primers - all with 357/158's jacketed. The results were conclusive. With magnum primers, I got less velocity and high-pressure signs much earlier in my work-ups. Standard primers yielded more velocity, more consistency, and with no signs of pressure. Standard primers were the hands down winner.

If you worked up with mag primers, and talking middle of the road range ammo, you can likely just switch over to standard primers with most propellants. Exceptions abound - and HS-6 and more critically, W296/H110 being examples. Performance may change however. Also, if you're talking top-end loads, I wouldn't recommend it. Any time you're at max pressure, making any change warrants a powder charge reduction and new work up.
 
Well stated! ^^^^

I'll only add that not all magnum primers are created equal so the comparison differences are not always equal. In general, though, a powder that ignites easily will tend to produce better consistency with the weakest primer you can find because that leaves velocity variations up to the powder charge you carefully measured. A powder that is hard to light up will have poorer consistency with mild primers because it is on the ragged edge of getting going where small things like the exact position of the powder in the case can make the difference between solid ignition and ignition with delays or even squibs.
 
Standard primers yielded more velocity, more consistency, and with no signs of pressure. Standard primers were the hands down winner.
Click to expand...

Imagine that, E.K. had it right regarding 2400 after all.:)

Don
 
I had the same experience with 2400 and .357 . My testing was done back to back with 158g SWCs. I didn't see a big difference, but I did expect a higher velocity with the magnum primer which I didn't see.

Example test,

13.5g 2400, 158g SWC, CCI-500,1270fps,16 SD, 49 ES, 13 Shots (liked)
13.5g 2400, 158g SWC, CCI-550,1263fps,15 SD, 56 ES, 14 Shots

This is the load I'd use with 357 if I used 2400. However I like to keep my loads under 1100fps for general purpose, so don't load it very often.

Like above, I normally use standard with most powders, but there are a few that perform better with it, and a few a Magnum primer should be used.

HS-6 for example should use a Magnum primer. At least in .45 Colt where this test took place. Again a back to back over the chrono. In my favorite load for the powder, the Magnum primer had an ES of 52 over 29 shots, while a standard primer yielded ES of 96 over 29 shots. Almost double....
 
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Example test,

13.5g 2400, 158g SWC, CCI-500,1270fps,16 SD, 49 ES, 13 Shots (liked)
13.5g 2400, 158g SWC, CCI-550,1263fps,15 SD, 56 ES, 14 Shots
Click to expand...

Are you seriously suggesting a 7 (seven) fps difference is justification for not using a magnum primer??
 
During the shoratge I was w/o a chrono due to my friend scragging mine. However my empirical results come close to Nick's. Certain powders respond to magnum primers...some not so much. However I load in So. Cal. and I also found that W296/ H110 isn't as tempermental in our conditions. I've got many loads that are safe & sane with standard primers. I've got some go to 30 carbine & 357 loads.

That said..... YMMV as well as your conditions. I've also got some "You gotta be kidding me" loads that are spot on but you wouldn't have guessed that. One is a softball 44 Mag. R.D. load.
 
44Amp, I saw a slightly lower velocity with a magnum primer in .357 cartridge rather than higher. That was what I was trying to point out there. It's 'odd'. With most other powders, I'd see a slight jump of velocity, usually 20-25fps with a magnum primer in back to back tests. Trail Boss was even more ... like 73fps sometimes. That said, certainly no 'need' for a magnum primer in this case. I did mark the non-magnum load as 'accurate', so assume it shot better for me at the time.
 
I guess most of the industry is "lazy" then. Lyman, Alliant, and the more recent Speer manuals appear to be about the only ones specifying a standard or a magnum primer for some cartridges depending on the particular load (powder).
 
rclark wrote:
I had the same experience with 2400 and .357 . My testing was done back to back with 158g SWCs. I didn't see a big difference, but I did expect a higher velocity with the magnum primer which I didn't see.

Example test,

13.5g 2400, 158g SWC, CCI-500,1270fps,16 SD, 49 ES, 13 Shots (liked)
13.5g 2400, 158g SWC, CCI-550,1263fps,15 SD, 56 ES, 14 Shots
Click to expand...

I got your point and like your thinking of testing primers!
I only load 2 recipes for my 357:
A practice load using green dot with std. primer and
A hunting load using H110 with a mag. primer.

I never thought to test (or cross test) type of primer.
 
I never thought to test (or cross test) type of primer.
Click to expand...
Yeah, during one of the primer shortages I got the idea to test back to back for a few of the powders I use to see how much difference it made over the chrono and on paper. Back to Back allows one to test in exactly the same light conditions over the chrono and in the same outdoor temperature , so should be more 'accurate' comparison. Also the same lot of 'brass' is used and since loaded at the same time, the powder throw, seating depth, crimp is all the same. I load 15-30 of standard CCI, same with Magnum primer. A couple tests I included the WLP as well.

I use Green Dot too for my general purpose load too.
 
I load a lot for .357 Mag. When using 2400 powder and 110 grain bullets I find the use of magnum primers results in cleaner burning. I found the load recommended just above starting in the Speer handbook to be fine. I never tried the maximum and do not have a chronograph but accuracy was outstanding. I tried this in my 6" Model 19 and also in a friends 2" snubby Model 66. The snubby has some unburned powder from this load and quite a fireball. Great way to get the indoor range all to yourself.

With 158 grain SWC's Unique powder is used with standard primers. Wax lube results in smoky / dirty loads but again accuracy is exceptional in my 6" Model 19.
 
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