why mag primers for 'ball' powder

[wtr100]

From  time to time I read that mag primers are needed or  maybe just better for 'ball primers'.

Anyone know why this would be?  Ball powders seem 'finer' that stick powders, wouldn't they ignite more easily.

A few years back I loaded AA2460 and AA2520 in M1 Garand ammo and used regular Federal primers with no issues - although I hear the Federal primes was not a great idea.   

[m25operator]

WTR, in my experience, handgun ball powders like H110 and ww 296 do like a magnum primer, ww 231 does not care, look at burn rate, slower burning powders do like the mag primer, in rifle powders like ww 748, does not seem to make a big difference, but really slow burning powders, like you use in magnum rifles, I highly recommend Mag primers, the 1 thing about ball powders is case density, those little spheres compact very well and often have a dead air space above the powder when horizontal if not a heavy load, and that can cause a flash fire, where the spark go's across the top and ignites the whole powder charge at the full length of the cartridge, instead of beginning at the base and making a progressive burn.

As to Federal primers, they are my favorite, expensive, bulky but the best IMHO, except, for the match primers, they a spotty in cold weather as far as ignition, bench resters  in cold weather will keep them in an insulated case to keep the cartridges warm until time to shoot.

[Pecos Bill]

The reason mag primers are recommended for some ball powders is that these powders are hard to ignite and a mag primer will give more consistent ignition and velocity. Tis, of course, means more potential for better accuracy. Standard primers WILL ignite the slower burning ball powders (don't go screaming about "I've been using standard primers for years with W296 and it works fine" I know it will so carefully reread the line above) but mag primers work better. The AA powders you mention are ball type powders but are easy to ignite and don't need mag primers. You mention Federal primers, they are good primers and are no better or worse than CCI, Win, or Rem. A lot of people like to use them in handguns because they have their triggers lightened to the nth degree and need the soft cup of Federal primer to get ignition.

Research your loads in one or more of the published manuals and follow the recommendation therein and you can't go wrong. I have 6or 7 of the latest manuals in my reloading room. I only have 2 friends who I trust enough to use their loads and I have a bunch of friends who load their own. i a picky old man but I've got all my fingers.

Hope this helps, I got to rambling there.

Pecos

By the way isn't W231 a flake powder?

[billt]

A lot of the Ball propellants have a coating on them, much like "M&M's". This is for a couple of reasons. First and foremost is to control their burn rate. Usually, but not always, this coating retards ignition slightly, and once it starts it allows it to continue at a much slower rate thereby building up pressure in the cartridge slowly as the bullet starts it's journey down the barrel of the gun. Secondly, it gives the powder a certain "lubricity" which allows it to flow very easily. It is one of the reasons this stuff is such a joy to reload with. It flows through a powder measure like water through a faucet. A bit like a zillion ball bearings rolling off a table top.

A magnum primer creates a much hotter flame that burns through this "coating" much faster and allows for quicker, more positive ignition in the process. Believe it or not when Ball powder is manufactured this "coating" is applied underwater. This is done to assure safety during the manufacturing process. There have been a few powder plant detonations in years past that have resulted in a few deaths in the process. Containing at least part of the manufacturing process under water cuts down on much of the explosive dust that is generated.  Bill T.