Solved: 44 Magnum Over-Pressure Mystery

Quick update for everyone- less than a day after posting a video and article describing some dangerous looking pressure signs with 44 Magnum, you all helped me track down the problem with help from my iGaging 400x WiFi microscope!

You’ll want to read my previous story to get a complete run-down on the issues I was seeing with my 44 Magnum loads, kind of scary!

The Culprit: Bad Primers

In my investigation, I had ruled out the following:

  • Overcharge / over-velocity
  • Bullet seating depth
  • Bullet diameter/mis-match
  • Oversize primer pocket
  • Wrong primer

And it was two emails from Ultimate Reloader subscribers (minutes apart) that helped resolve the issue. From reader #1:

First: Please do not expose my name. In my case it was WLR primers. The reason for blowout, was a crack in the primer cup. Se pictures.

And here’s the picture that reader #1 sent:

Does the primer on the left-hand side look familiar (see my image above)? My cracks were not that large, they were hard to see by the naked eye, but it’s clear that the same thing was going on.

Reader #2 did not send images, but shared the same result!

This is where my iGaging microscope came in handy- I did not see any cracks when looking with the naked eye, but all that changed at 400x magnification. Here’s a picture of the complete setup:

In case you are interested in this microscope, you can check it out here: https://ebay.to/2BJfeTX

So it is now solved! I can now resume loading the original load, and not worry about these issues as long as I use the right primers. I’ll be reaching out to Winchester to find out more about this issue. Thanks again everyone!

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Thanks,
Gavin

6 thoughts on “Solved: 44 Magnum Over-Pressure Mystery”

  1. That makes sense. There were a lot of bad comments on Winchester primers ~2 years ago and some earlier. It was so bad that if a person wants to take a chance they can pick up Winchester primers cheaper now since people started avoiding them.

  2. I learned something so thank you for that. Just wondering if the cracks explain all your symptoms. The powder blow-by I can see. What about flattened primers and I thought you mentioned case bulging.
    Having S&W in 45ACP, 357 8 shot (thank you moon clips) an a limited 44mag with interchangeable weight system as part of full under-lug, I was always under the impression that max loads were only to be fired in either in Thompson Contenders or the beefy Ruger versions owing to the removable side plate which weakened the frame.

  3. Hi Gavin,
    Glad you were able to put the Igaging microscope to good use in solving your overpressure problem.
    I have been unable to find a source for the XY table that you show on the website.
    Igaging has not responded to my request for how and from whom to order the XY table. Apparently they also have not responded to your inquiry on my behalf several months ago. Thanks for trying though…. apparently Igaging doesn’t need business from potential customers trying order one of their products… go figure!
    I continue to enjoy your website very much.
    Regards,
    WMiller

  4. I had the same issue in 44 Magnum with Federal large pistol magnum primers 4 or 6 years ago. Some would crack on the outside radius just as yours did and were hard to spot. Others would show as a linear crack radially from the primer indentation to the outside radius of the cup. I went back to CCI primers and haven’t had the issue since.

  5. I like the walk through that you did. There was a comment on the “unsolved” video that I got hung up on a bit. There was mention that the fired cases appeared excessively bulged?

    I’m going with the assumption that it turned out to be a non issue, but I wondered if the bulged appearance seemed more than what it compared to in the past. I find your outdoors .44 carry comments timely and helpful. Take care.

  6. I had Winchester rifle primers pierce with known good loads. I suspected bad metal or thin primers…pistol primers packaged as rifle…just didn’t know. Called Winchester technical wanted sample of my reloads. Sent them. They called back with result, bad batch of primers. The rep didn’t know if it was thin metal or metallurgy. I had two bolt faces marked as a result. He offered to replace the bolts but one was a Swedish Mauser, irreplaceable and the other was a hunting rifle…Rem 700… Neither shot any different because of it. I opted for a case of 5000 primers…

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