12/6/2023 0 Comments 9mm primers and powder![]() ![]() I found it interesting that sometimes, using Magnum pistol or small rifle primers results in less velocity. In chronographing my reloads, about the most difference in velocities that I can recall between standard small pistol primers and Magnum pistol, or small rifle primers, in these cartridges is about 25 FPS. The reason I have used these primers in these cartridges, and 9X23 Winchester too, is to better resist primer deformation, i.e., flowing/flattening/piercing etc. If you can point me to any pressure data you think might help I'd much appreciate it.Xpierrat, FWIW I have used Magnum primers in max 9MM and 38 Super loads with no issues. I'm not trying to convince myself to go would just be nice to know how big the "pucker factor" is. Are we talking about an increase of 5K above 35K or 20K above 35K. It would be nice to know if the issue is in big factors of pressure created or "slightly" above in the primer ladder. ![]() Sure would be nice to get some data on pressure behavior of the various primers.haven't found any to date. One can almost count the grains that go into a 45 shell. I'm sure a half-empty case of 4.3gn of powder reacts much differently than 40-50gn in a rifle case. I thought I could derive some correlation from rifle data as to slower or faster burn rate pistol powders but there doesn't seem to be a whole lot of difference between pistol powders anyway. I can't imagine I'm the only one who's considered it. It would be nice to see some data around SRP Mags outside rifle loads but couldn't find any. (that could put somebody on the wrong track !) Surprisingly, the Mags created less fps for the same charge. I did see some data where there was no appreciable pressure difference between SPP, SRP and Mag SPP.all in the low 30K's. That kind of increase over published max must have some correlation to pressures of which I would think minimum load with the Mag primer would not exceed the pistol's capability. I haven't looked at the +P data to see what that might generate. To get the same 890fps I'd need to go several steps above the published max. Currently my shells come out clean with 4.3gn/Titegroup (less than 800fps) compared to my Federals advertised at 890fps (obvious signs of escaping gases). Thanks, Marc.I understand there could be issues with pressures.I'm hoping I would see some indication with the first shot. You may do these experiments without problem, but then again you might not. When you do this without an instrumented chamber, you are experimenting blind with high pressures (35,000 + PSI). When you substitute them, you are doing your own experimentation. Otherwise there would not be separate products being offered. The different primer types are made and sold because they have different spark heat and projection characteristics. Not the single pressure peak, but all of the possible multiple pressure peaks generated by the load were found to be within the SAAMI specification that the gun chamber's manufacturer respected when the gun was built and proofed. They document loads that have been measured to be safe. This is what the manufacturers do for you when they test loads in their laboratory and publish them in reloading guides. That can only be measured properly with an instrumented chamber and pressure measuring tools. Those pressures happen as a result of the powder ignition characteristics, the initial engagement of the bullet ogive in the barrel rifling leade, the friction of the gliding surface and the powder burn rate. Internal ballistics are involved, and that involves the one or multiple peak pressures generated before the bullet exits the barrel. Your chronograph doesn't measure what is actually happening when you substitute primers in a load.
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