Drove a good distance today to purchase some supplies. When I came home I found that I had picked up the wrong size primers for loading 9mm. I mistakenly grabbed magnum primers instead of regular ones. Can I use these or am I going to have to take another trip after the snow storm goes away.
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Primers
- Thread starter njjr1989
- Start date
Welcome to the forum.
The most pressure change measured for primers that I am aware of is 10% by M. L. McPherson. So figure if you knock your powder charge down 5%, then check velocity if you can, nudging the load back up until it matches, and you'll likely be no higher in pressure than you were before.
With some magnum primers the cups are thicker, so you increase the chance of getting failures to fire if your gun's had its springs lightened or anything along those lines.
There can be accuracy effects. The problem is that in small capacity pistol cases primers can sometimes start unseating the bullet before the powder gets fully lit. This can lead to erratic velocity and barrel time. You can but try it and see.
The most pressure change measured for primers that I am aware of is 10% by M. L. McPherson. So figure if you knock your powder charge down 5%, then check velocity if you can, nudging the load back up until it matches, and you'll likely be no higher in pressure than you were before.
With some magnum primers the cups are thicker, so you increase the chance of getting failures to fire if your gun's had its springs lightened or anything along those lines.
There can be accuracy effects. The problem is that in small capacity pistol cases primers can sometimes start unseating the bullet before the powder gets fully lit. This can lead to erratic velocity and barrel time. You can but try it and see.
Average Joe
New member
Yes, no problem, just stay below max and you are fine.
Thanks for the reply's I will give them a try. I can always take back what I don't use and exchange them. I usually do not load my ammo up to full strength anyway. At the ranges I shoot pistol, it isn't needed and I don't shoot any competition. Most shooting is point and shoot at man size targets.
You may be right when it comes to mail orders, but I have a feeling that in some cases where an obvious mistake was made for the sake of good customer relations, you might be accommodated.
Not going to be a problem though. I am told that the main difference to between the two is that magnum primers are harder and in some cases the firing pin might not strike it hard enough to make it fire. Since I will be using them for 9mm to fire in my unaltered Glock, I don't think that will be a problem.
Not going to be a problem though. I am told that the main difference to between the two is that magnum primers are harder and in some cases the firing pin might not strike it hard enough to make it fire. Since I will be using them for 9mm to fire in my unaltered Glock, I don't think that will be a problem.
What makes them "magnum" is they produce a larger volume of gas. Part of a primer's purpose is to provide some initial pressure to the case to help the burn get under way. When a case has larger capacity, that takes more gas to accomplish. See this article to get it from the horse's mouth, so to speak. The thicker cup is just because they are more likely to be called on to seal the primer pocket in a higher pressure round.
OP, which primers, what load (bullet,powder), and what gun? Lots of us competition shooters used magnum primers during the "primer recession" My load is a Bayou 125TC over 4.2 grs of TiteGroup at 1.100" out of Glock 17's. It measured about 20fps faster thru my chrono. Because they are harder, they may not be happy in a gun with lightened trigger springs. Like others have said, back off your charge weight off and start from there. I have used over 10,000 CCIs
Average Joe
New member
Still, the question is can I safely use them in a 9mm cartridge?
Yes. As stated above, stay below max load, and you are fine.
Yes. As stated above, stay below max load, and you are fine.