Magnum Primers?

songdog

I have always used a mag. primer with my mag. rifles and standard primers with all of my other rifles. Lately I have been reading in a few places that suggest using magnum primers in your standard non-magnum rifles. What is the purpose of doing this? Does it allow for better ignition, faster? Why is a magnum primer only suggested with some powders and not all powders? Will a magnum primer cause some slower burning powders to ignite to quickly causing your barrel to blow? Thank you for your replies in advance.songdog

22WRF

If the loading chart calls for standard primers then thats what I use. You answered your own question, yes powder burns fast resulting in higher pressures.Magnum primers are needed for large capacity cases.Load data in the chart was developed with the suggested primer, even using winchester when the load data says CCI will make a difference.

mr whitetail

Magnum primers are supposed to burn hotter and longer to ignite slower, harder to ignite powders assuring a complete uniform burn. As a rule of thumb, (all rules can be broken) when you substitute a magnum primer for a standard primer back off your powder load by 2 grains. Regardless of what you know or think you know, always, start from your min. loads and work up again, checking for signs of pressure. When you reload slow burning magnum powders in non magnum chamberings (I cringe while I write this) you can use magnum primers but back your load off 2 grains. For example, I use H4831 in my 270 with magnum primers, start at starting loads, watch for signs of pressure and work my load up, not exceeding the max. load but remaining below it by 2 grains. Be careful, be safe, when uncertain read the instructions and if you are still unsure don't do it!

songdog

One of my reloading manuals had suggested that i use a magnum primer for my 22-250. That was using h380 powder which i believe is a pretty slow burner, but with the grannuls being so small i do not understand why. Another question for you all. IN a small caliber such as a 22-250 would it be best too use a fast burning powder as compared to a slow burning powder. Will one type of powder produce better groups, or is that mostly based on the construction of the rifle.songdog

Iconoclast

songdog, mr. whitetail is shooting .001 MOA, take his advice to heart. Your best advice for loading the .22-250 or anything else is the published guides. If you change anything, start over again. If no published data lists the combo you want to try, there's 99.9% probability that it's not a good choice, for reasons of safety and/or accuracy. And yes, the your choice of components/combinations can have a major impact on accuracy. Which is why a load carefully-tailored to an individual firearm can produce radically better results than one-size-fits-all factory loadings. But there ain't no shortcuts - no safe ones, anyway. Burning rates are dependent on several factors, size is only one; others include: specific composition of the powder, configuration (e.g., flake v. extruded IMR), type & amount of retardant, etc. The effects of these variables individually are often, *but not always,* intuitive, and the combinations can be vary enormously.[This message has been edited by Iconoclast (edited 12-11-2001).]