Large Pistol vs Magnum primers chrono results

[Larry Gibson]

I tried small pistol magnum primers once in .223 and got pierced primers and gas cutting on the bolt face.

Apples and oranges.....good lesson learned w/o too much damage.

This thread is in regard to pistol cartridges that generate much less psi than cartridges, particularly rifle cartridges, that develop a lot more pressure. Even some of the newest handgun cartridges that develop high psi's should be used with the recommended rifle primers with top end loads.

[centershot]

Very interesting data presented here, a "Thank You" to Larry for his work with the Oehler ballistic lab!

I, like most here, use a combination of flake, stick and ball powders. Some require a magnum primer for best ignition. I found myself having to stock mag primers for those powders and "regular" primers for others, just as most of you guys do. It seemed like I was "spending money twice", if you know what I mean. So, I stopped buying regular primers. I reasoned that the mag primer will work with any powder if it will work with powders that are harder to ignite properly. OK. Now, I don't shoot bullseye pistol, or any other game where a small increase in group size will cost me the match. I have found that mag primers work perfectly in my loads, light or heavy, and I don't need to buy two types of rifle and pistol primers. Even in my gallery loads for indoor range use, 5 grains of Bullseye and a 180 gr. cast boolit sparked by a mag primer works great. I've never been left wanting better accuracy that I couldn't get with a little load development. YMMV.

[MessybearII]

Great info Larry!
If you guys are interested in the large pistol side of things, and want to know more about large pistol primers in lab testing, contact the head ballistitian at Western Powders.
He can provide pressure results from ball Powders and different primers in the lab.
Pressures were VERY impacted by primer changes! Again this is lab testing.

[David2011]

Mattri, a best guess would be that with TB (assuming you mean Trail Boss) you can't pack enough powder into a case to get high pressures. As with Larry Gibson's data and Bullseye, a case full of TB will only develop so much pressure regardless of the primer used. As others stated, I would expect different results with different powders.

[MT Gianni]

Do not expect primers bought in the last 5 years to have the same formula make up as those from 25 years ago. As with all things we reduce when changing components and retest.

[MUSTANG]

Do not expect primers bought in the last 5 years to have the same formula make up as those from 25 years ago. As with all things we reduce when changing components and retest.

Good point. Also; reliability can change over time. I can remember a single incident of a primer that "Failed to Fire" for me between the 1970's up to 4 years ago. I can look at my reloading/test firing notes and see at least 2 dozen "Failure to Fire's" since January 2019 using "Current Production" primers (These are NOT part of my testing using primers for rifles in pistols; not my "Reloading" primer efforts). Small sample of one person; but my observation is that today's production of primers has less quality control based on "Failure to Fires".


Taking that observation in a different direction; I collected maybe 5 or 6 rounds on ranges during the 1970's to 2019 period of commercial ammunition that had primer strikes but did not fire; but I have almost three coffee cans full of various caliber/manufacturers commercial rounds with primer strikes but "Failed to Fire".

[fredj338]

What I have found in several caliber is it is all about the powder burn rate. Faster powders dont seem affected as much with the mag primers. Slower powders show a greater affect. In my 357sig load running std vs mag primers using AA#9, mag primers are 100fps faster.

[charlie b]

Interesting about failures. I shoot more now than I ever did, but still only a few thousand in a year. The past three years I have not had one primer failure.

[fredj338]

Do not expect primers bought in the last 5 years to have the same formula make up as those from 25 years ago. As with all things we reduce when changing components and retest.

You of course have something that substantiates that? Unless you are running max loads, any modest primer compound change isnt affecting pressures.

[fredj338]

Interesting about failures. I shoot more now than I ever did, but still only a few thousand in a year. The past three years I have not had one primer failure.

Only primers I have ever had issues with were Wolf SP. I would never rely on them for anything serious.

[Thin Man]

I work at a commercial shop that has an indoor range. For the past 10 years I have seen a small but regular amount of FTF rounds turned in to us. With the vast majority I find the fire pin indent in the primer is very shallow from a light hammer/strike impact. The second most common FTF rounds are the primers where the fire pin struck well off-center of the primer. It was common that I would re-test these rounds (loading a single cartridge only) in a known reliable firearm to re-test and the vast majority of these did fire. The third lot of tests involved grand-dad's old handgun with the aged ammo he had bought when he got the firearm. These rounds usually did not fire. Just more to ponder.