Primer 101,please

[Matt1911]

Please explain a little about primers for me please.
How much hotter is magnum,vs standard? Whats the differnace between rifle and pistol,(i ask because one Win. recipe calls for small rifle primers,with 296). For accuracy,is there a "best" primer to use?,like match bullets? What pro's and con's are there useing magums in place of standard?

 

[braindead0]

I'll do the best I can...

Magnum vs. Standard primers:

well, I don't think there is any strict 'X' hotter than. If a load calls for magnum, you should probably use magnum primers. Many times a load may call for magnum primers to ensure good ignition. Using magnum in place of standard primers is not a good idea generally, it can lead to increased pressure.

Rifle and pistol primer diffs, I suspect the pistol primers burns faster.. but I'm not 100% sure on that.

As far as the 'best primer'. That's an area that you'd just have to experiment in.

One thing you may notice is that primer brands have greatly verying 'hardness' ie: ease of ignition.. Roughly in this order from hardest to softest:

CCI
Winchester
Remington
Federal

At least that's been my experience, I have at least one gun that will reliably ignite only federal primers (even though others have claimed the Remingtons are as soft).

 

[MonkeyMan]

In general, the cup material is thicker in rifle primers due to the higher pressures generated. Most handguns won't give enough thump to ignite rifle primers reliably. As to magnum vs. standard pistol primers, I haven't noticed much difference between the two in what little testing I've done. Powder and bullet load being the same I get a higher velocity from a mag primer as opposed to a standard but not significanly higher.

DISCLAIMER!! None of the loads I tested were anywhere near MAX. Approach max loads with caution.

One thing I have noticed is magnum primers seem to give better performance in colder weather than standard.

Just my own observations, YMMV.

 

[Mikul]

I was reading a section of reloading for the .44 magnum. It said that to use the loads listed with non-magnum primers, to increase the powder charge by 1 grain.

This may not be true for all loads with all calibers, but it does give a starting point.

You could play with it. Start 10-15% below max and work your way up until you see ANY sign of over pressure. If you work up slowly (0.1 grains at a time for pistol), you should see minor overpressure signs long before things get dangerous.

 

[Timothy]

Like Monkey Man says. rifle primers have a bit healthier cup among other things and may not always be reliable when used in pistol applications. The thing you don't want to do is use pistol primers in rifle applications. There is a high risk of pierced or blown primers. Although the diameters of small pistol and small rifle are the same as well as the large pistol and large rifle there is a small difference in hieght. IIRC, the rifle is a tad higher.