Load data: 357 Mag Winchester primers (WSPM for handgun) vs (WSP for rifles)

[schuetzen]

I am looking at the "Loadbooks" data for 357 Mag.  Under the Hornady bullets (pg 1) it lists using Winchester WSPM (magnum primers), while under the Hornady bullets (pg 7, Rifle section) it specifies Winchester WSP primers.  As I am interested in loading for both handgun and rifle, I wanted to ask if this appears correct?  Can I use one type of primer for both rifle or handgun?

Is this because the handgun (shorter barrel) needs higher priming ignition and rifles have a longer distance barrel to travel, do not?

[Dand]

From what you post, I understand the manual recommended WSPM- small pistol magnum primers for some loads and WSP- small pistol primers (standard) for other loads . Neither is a rifle primer - Winchester rifle primers would be WSR or WSRM. As I understand it, hand gun cartridges have a shallower primer pocket than rifle cartridges and only pistol primers, or mag pistol primer fit right. Rifle primers might not seat properly and protrude from the base of the case. I did it once by accident in a small batch of 41 mag - but I caught the mistake before charging the cases, and punched out the offending primers. I was being careless and didn't look closely at the primer packages.

I believe the priming charge in pistol primers is usually smaller than for rifles as usually a handgun cartridge has less powder to light than most rifle cartridges.

Pistol primers are often a little softer than rifle primers as they usually don't take as much pressure and hammer drop from a handgun may not be as strong as a rifle firing pin.

For some high intensity handgun cartridges, I think 357 MAX (don't confuse 357 MAX with 357 magnum), 454 Casul and similar - rifle primers may be needed - I'm going on memory here - check a reliable load manual.

For a while Winchester made only one primer for each size: pistol, rifle and they were designed to work with standard and magnum loads - I liked that system. I think they were relatively hot primers designed to ingnite the Winchester ball powders - ball powder loads very often call for magnum primers due to being a little harder to ignite.

As mentioned earlier, often mag primers are recommended for hard to ignite ball powders or large volumes of slower powders - like 296, H110. Standard primers are usually recommended for flake or fine grained powders in small to medium charges - powders like Bullseye,  Red Dot, Unique, Herco and 2400.

For standard level 357 mag loads in a rifle or handgun I would stay with pistol primers according to the load recipes. I have 41 magnum rifle and handguns and follow this system. Barrel length has nothing to do with it.

I'd strongly suggest you get a full reloading manual like the Lyman, Speer, or Hornady and carefully read the chapters on reloading at the beginning of the book(s) - appears to me that you might find it helpful.

Be safe and have fun.

[schuetzen]

From what you post, I understand the manual recommended WSPM- small pistol magnum primers for some loads and WSP- small pistol primers (standard) for other loads . Neither is a rifle primer - Winchester rifle primers would be WSR or WSRM.

Thanks for the reply.  I apologize if there is some confusion in my above description.  There is no reference to WSR or WSRM primers in these recipes I am referring.  The section under Hornady bullets lists 357 Mag handgun load data and 357 Mag rifle load data.  The handgun load data begins with basic description of the case specs and primer using WSPM.  The rifle load data begins likewise with case specs and primer using WSP.

There is no reference to 357 Maximum in this discussion, so I don't want to confuse the issue further.  I am interested in load data for 357 Maximum as well, but this Loadbook is only for 357 Magnum.

I plan to pick up one or two more data loading manuals next, but I want to begin here to get an idea of which one or two recipes and therefore which manuals to look for next.  In the mean time, for those who have the Loadbook for 357 Magnum, they may be able to verify, possibly explain or give there opinions from experience of why the two different primers (WSP and WSPM) are used as described (or if there is a possible error).

I have one other load manual presently.  I picked up the Lee Modern Reloading manual as I plan to try some of the Lee equipment (Lee Classic Loaders and Lee hand press) to begin with.  I was disappointed that their data does not reference specific bullets by Mfg, but references just generically "125 Grain Lead Bullet" or "140 Grain Jacketed Bullet".

[stimpylu32]

I am looking at the "Loadbooks" data for 357 Mag.  Under the Hornady bullets (pg 1) it lists using Winchester WSPM (magnum primers), while under the Hornady bullets (pg 7, Rifle section) it specifies Winchester WSP primers.  As I am interested in loading for both handgun and rifle, I wanted to ask if this appears correct?  Can I use one type of primer for both rifle or handgun?

Is this because the handgun (shorter barrel) needs higher priming ignition and rifles have a longer distance barrel to travel, do not?

The short answer is sometimes , it depends on the type of powder being used , the amount of powder used , as well as the bullet type & style . As a general rule , you can in most case's get by with standard small pistol primers .

As for the difference in the data you have ( just guessing here ) as I don't have that load book , what you may find is that the powder charge is higher for the rifle data or the type of powder is different .

stimpy

[Dand]

In my opinion the load books are ok for experienced reloaders (I don't like them myself).  Its like having the ingredients list for making a cake without the instructions on how, when to combine the ingredients and at what temps to bake it. The real manuals provide you with a lot of important knowledge on the hows and whys of various reloading practices.  Typically a specific primer is recommended for a particular type and amount of powder - not whether it the cartridge will be fired in a short or long barrel.  

Like Stimpy said, there's a chance more powder might be recommended for a rifle than a handgun as a lot of rifles can take a little more pressure (NOT ALWAYS!!!) or a longer bullet. Frankly where I have several guns of the same caliber, I do not like to have ammo that can only be safely shot in one of them - too easy to make a bad mistake.

Read the front portions of the Lee Manual. I think it has some very good discussions.  I need to read those as I still don't get their volume loading system.

If  you are loading 357, I'd think the Lyman Book would be a very good one as it lists a lot of cast bullets loads. You may want to try cast or lead bullets to save money. Plus Lyman isn't beholden to any single brand of bullet and lists loads for several brands.  

Back to the Lee book: in the 357 one may often change one brand of 158 jacketed hollow point  (or cast semi wadcutter) for another of very similar construction AND SAME WEIGHT without a lot of worry, as long as you aren't on the very ragged edge of going past maximum charges.  Back off a grain or two and work up.  NOW DON'T work up a max cast bullet load then start loading jacketed bullets with the same charge.

But this is all the stuff you'd learn by buying and reading a real loading manual.

Good luck and stay safe.

[chutesnreloads]

My Lyman manual also suggests CCI550(magnum) primers for handgun and CCI500(standard)for rifle loads in .357 magnum.My guess is you are correct about barrel length.What I sugest is use the magnum primer and work the load up in BOTH the rifle and the pistol so you'll have a known safe load for each.

[schuetzen]

My Lyman manual also suggests CCI550(magnum) primers for handgun and CCI500(standard)for rifle loads in .357 magnum.My guess is you are correct about barrel length.What I sugest is use the magnum primer and work the load up in BOTH the rifle and the pistol so you'll have a known safe load for each.

Interesting.  I guess it would sound reasonable, if the rifle round was optimum for the longer rifle barrel, shooting it in a shorter handgun barrel may need a little more boost with a magnum primer.

I will be putting the Lyman manual next on my list to order.  I do plan to try loading with cast lead bullets.

[Dand]

The current issue of Handloader Magazine has an article about loading different brand but same weight bullets in the 45 Colt using the same powder charges, case, and primer.  You might find it interesting.

I just had a thought that maybe the primer difference you see in rifle vs revolver may be related to the cylinder gap in the revolver - less time for the cartridge to get up to full power before some pressure gets released by the gap.

I wonder if they do the same thing for 44 revolver and rifle?  I''l have to look.

[mechanic]

When I started loading for a rifle in 357 I had an issue with perforated primers.  I have now worked up loads with SR primers in all, even my 38 revolver, and have no issues.

Remember I said...worked up loads.  Some combos were discarded for various reasons.

Ben

[Dand]

Interesting comment Mechanic.  I HAVE heard of using rifle primers in some handguns where there was high pressure or other issues like you experienced.

Schutz, in my Lyman manual 48, for 357 rifle & pistol, they specify CCI 550 (small pistol Magnum) across the board.  I seem to remember that issue had several primer changes from the prior issue forcing me to reconsider some of my loads - as max powder loads (in 41 mag I think) were substantially different from the 47th manual.

Makes me wonder why all the switch-around Lyman did. I wonder what the 49th issue says?

[southernutah]

It is really simple, both pistol and rifle are designed to shot the 357 mag pistol ammo. Just load to the specs you chose. I load and use the same in pistol and rifle

[SHOOTALL]

Some WSP primers are marked for standard and magnum loads go figure . But the type powder matters .