Primers

[jjavedas]

What's the difference between large pistol primers and large magnum pistol primers? thanks JJ

[Kenk]

Welcome jjavedas!

[woods_walker]

The difference, basically, is that the magnum is a "hotter" spark than the standard primer. But this doesn't really explain anything as there is no set rules or standards for primers.

To give you an example-

I have a 10mm load that uses a hefty charge of Hi Skor 800-X. If I use a standard primer I get pretty good accuracy but my Standard Deviation and Extreme Spread are not as low as I would like. When I keep everything else the same but change to a Large Pistol Magnum primer I still get pretty good accuracy.

though my numbers are MUCH better on the chronograph, but they only run 10-15 FPS faster!

In contrast, I have a .41 magnum load for a 240 grain LSWC and Unique.  With a standard primer I get good speed and good accuracy, If I switch to the magnum primer, pressures spike and I split cases.

Or I use the Winchester Large Pistol "Standard/Magnum" Primer and it makes no difference at all. Sometimes you use one or the other because your load works best with it. Sometimes you use it because you are developing "off-book" or wildcat loads. No matter which reason, changing primers is not for a beginner reloader. Make a mistake and you will destroy guns, eyeballs, fingers and more.




My very enthusiastic suggestion is to stay with the primer that your load books list. Very educated people were paid huge sums of money to develop safe loads for us reloaders.

[Kenk]

I love it, and yes, that's why they write these manuals and not myself 😀

[woods_walker]

I love it, and yes, that's why they write these manuals and not myself 😀

RIGHT!!!   

[rognp]

I have a Redhawk 45C and a Rossi Puma 45C. They both handle heavy(book) charges of H110/W296 with aplomb. The 20" puma will shoot well with Rusiian Tula or Wolf primers in almost any weather. Mostly the LPMagnum.  The Readhawk with the longer throat plus the cylinder barrel gap will not handle the mild Russian primers with an occasional hangfire(just detectable) BUT it has stuck 2 bullets in the bore. Even though these primers are labelled magnum they are quite mild(and quite accurate).  CCI magnum primers completely eliminate the ignition problem with a slight degradation of accuracy. Wound up with a fair supply of the Wolf/Tula during the "Bobo" drought years and still using them up. Standard LP are great in the 10mm, better than most others in accuracy, on paper as well as the tiny stack of fired brass in one small spot. I havent chronoed recently but Id bet sd is very low.

[The_Shadow]

jjavedas, welcome to the forum>

Two main differences of standard and magnum primers can be the amount of mixture or slight differences in the mixture itself.
The flame propagation is one aspect and its brisance is another.  Brisance is a shattering affect that drives the flame deeply into the powder charge.

https://arxiv.org/ftp/arxiv/papers/1203/1203.2701.pdf

[Trapper6L]

My very enthusiastic suggestion is to stay with the primer that your load books list

For someone that maybe only loads for one or two pistols, this might be viable. But don't expect to use the exact data and get the exact same results. Differences in chamberings, bores, etc will have you going nutz thinking something is wrong. Even temperature will effect most loads as will elevation. I learned about elevation when I shot on a traveling benchrest team. If you are loading more guns than that, you might have to add onto the house to keep all of the different brand and brisance primers. For years I shot nothing but Remington. Then a bud opened a Federal Distributorship and I was buying in volume from him all of Federals components. Lately I've been switching pistol primers to Winchester. I only have to stock one small pistol primer, one large pistol primer, one small rifle primer, but due to most of the large rifle primers are used at extreme ranges, some of which are bench guns, I'll be staying with the Federal 215M. For pistols, I see no observable difference in accuracy and if anything, seems like groups are a hair tighter at 25 yds where I shoot pistol. Moving to the Winchester primers has allowed more room in the reloading room for things like more bullets, brass, etc. I guess I'm a pack rat of sorts considering all of the stuff in the reloading room but its all good stuff. Reloading is not the same game as when I started in 1972. I still have Hercules powders and Alliant. No, the powders they market today are not the same as the old Hercules but the data can get confusing unless you've lived thru the changes. I've got reloading manuals back to the 1930's, some of the loads by todays standards are just whacko. Then you've got some cartridges have been neutered so bad by lawyers that they no longer resemble the original. The 357 Mag comes to mind, as an example. I'm an old loader and my old advice is to keep things simple and condense when you can. That's one of the reasons Winchester is the brand to buy at my house. Geez, I'm working loads up anyway so the book primer is irrelevant. That's my view and of course, YMMV.