Experiment -- Magnum vs Standard Pistol Primers

[gene pool]

About a month ago standard small pistol primers were not to be found…at least not to be found unless one was ready to mortgage the farm to pay for them. However, small magnum primers were available. So I ordered enough magnum primers (at the regular price) to last the coming drought, assuming the drought lasts only a year of so. Wondering what the difference would be in loading, yesterday I ran an experiment using a chronograph. Below is the results of two 5-shot strings, one string with standard primers, the second string with magnum primers.

Cartridge: 9mm Luger
Firearm: Glock 17
Powder: 4.5 grains +/- 0 Bullseye (max. load)
Bullet: 124 grain FMJ Zero brand bullet
OAL: 1.169
Brass: PMC
-------------------------------------------------

Federal Small
Magnum Pistol
Primer (fps)

1124
1128
1148
1138
1121
Avg. 1131.8


CCI Small
Pistol Primer
(fps)

1138
1150
1107
1133
1128
Avg. 1131.2


Bottom line: It appears there is no need to adjust powder charges when using magnum primers…or at least for 9mm Luger, that is. In a week or so I will try the same experiment on 38 special, where the powder charge fills less than half the case.

Gene Pool

 

[BigDMT]

Each gun can react differently to primer changes. And different types of powder can react differently as well.

Then each brand of primer, Magnum or not, can give different results.

So it's always wise to start at average load charges and work your way up to Max loads when changing primers with any powder. Sometimes a standard primer can give faster speeds than a magnum primer.

Every firearm is unique and has it's own characteristics. You can predict the results, but you will never truly know until you try it. Which is clearly seen by your results. The magnum and standard are almost identical in velocity, but that does not mean that the magnum primer is not creating more pressure either. The length and properties of your barrel may only let a bullet go so fast regardless of pressure.

 

[mmcu]

I had the same problem as you did finding small pistol primers, so I did a similar test.

In my 9mm (using Federal Small Pistol and Federal Small Pistol Magnum primers) I simply had to reduce the powder charge by 0.1 grains when using Magnum primers to get the same velocity and recoil characteristics as my Standard primer load.

Powder used is Blue Dot, Winchester Brass and 125 grain Hornady Action Pistol (HAP) bullets with a COL of 1.164".

There really was not as much of a velocity difference as I had anticipated. However, other's results may vary......so always start low and work your way up!

 

[smoooth]

Had a similar situation as well, no chronograph, though. Loaded some .40 S&W for Glock 23 using Unique and 180gr jacketed flat points. Loaded some with CCI small pistol mag primers and some with standard Remington small pistol primers - everything else being equal. The Rem. primed loads had a much greater felt recoil and the cases ejected much farther away.......... pretty scientific, eh

I saw a sign at the gun shop today, from Remington, that they do NOT recommend using their small rifle primers in .223 and other such sized cases.

 

[DukeDuke]

I have done the interchange of mag primers with reg primers in all calibers I load for, pistol and rifle. I have friends /yes I do/ that also experimented with it, and we have concluded: no difference at all. My buddy was trying to match Hornady's superformance 168 a-max load in .308, using superformance powder, but wasn't getting the velocity, so he switched to mag primers fed 215, the rest being the same, he lost 70fps. Go figure!

 

[L.Sherm]

Be careful when switching to Mag. primers its not a one size fits all I have had 100+fps. gains switching to mag.primers