January 13, 2009, 05:48 PM | #26 |
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Well, it looks HOT to me. Primer sets off the charge, and then overpressure blows the little circle out of the primer into the firing pin channel. Upon ejecting, it flies out. That's my theory, anyhow.
Gunpowder is basically like guncotton. Nitrocellulose. I wonder if some of the nitro has sweated out? Like with Nitroglycerine sweating out of dynamite? Or perhaps things have changed with the powder since it was originally manufactured? Either way, I'd reduce charge simply due to increased recoil and the vigorous brass tossing. It's probably being pretty mean to the firearm.
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January 13, 2009, 05:59 PM | #27 |
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Didn't see the second picture. If there is no shiny brass, place where brass flowed or was shaved off, and from the looks of the primer edges still being quite rounded, I would check the firing pin hole. If that hole is to big the thin brass the cup is made from could just be blowing right thru it. That is very unusual. Did you have a pic of the ones that did not blow out the primer? Were they puckered up at all?
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January 13, 2009, 11:25 PM | #28 |
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OK, well another trip to the range, and I fired 50 rounds of factory loads and 2 rounds of my handloads. Well the recoil was harder using the handloads than the factory loads until the 2nd shot. The brass came out of the gun all jacked up. It almost looked like it was spun in a food processor. I can tell you this, I will NOT fire another of my handloads until I can pull the bullets, get rid of the old powder and reload with new powder. I appreciate all the information that everyone has given me up to this point. I do think that Shoney was correct about VOC's evaporating over time leaving the nitrocellulose behind causing me to throw HOT loads even though the weight was right.
Thanks, INGunGuy
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January 14, 2009, 09:48 AM | #29 |
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Try measuring setback
Pushing loaded bullets against the bench doesn't really tell you much about how they will act in the gun.
When I am setting-up a new auto-feeder load, I make some dummy rounds (no primer or powder) and carefully measure COL of each. The I load them in a clip and hand-cycle them through the action. I measure their COLs again, and don't accept the setup if it has changed on any of them. If my set-up passes that test, I take the dummies to the range and load a clip with one dummy under a factory round of the same bullet weight. I cycle the action by hand to load the factory round, fire it to auto-feed the dummy round, then eject the dummy round AND CATCH IT IN SOMETHNG SO THAT IT DOES NOT HIT THE GROUND OR BENCH HARD. I then measure COL of the auto-fed dummy to be sure that it was not shortened by the auto-feed. I do that for at least 5 rounds of dummies before I accept the setup for powder and primers. Then I work-up loads from "start." If I am using mixed-headstamps or change headstamps, I do this set-back test for EACH brand of case, because brass thickness and springiness DOES matter. I should add that COL reductions of one or two thousandths are not unacceptable amounts of setback. Even factory ammo may experience that. (You should try it in your gun with factory ammo, too). Even repeated hand-feeds with factory ammo will usually start setting it back after several cycles, although usually by only a couple thousandths at a time. That is why I am careful NOT to keep putting the same round of carry ammo back into the clip and hand-feeding it into the chamber to carry. I am even more careful with handloads or factroy rounds that I have auto-fed but not fired. Ejected live rounds go into a separate pile. After saying all that, I will add that, to me, your pierced primers look like a firing pin problem to me. But, the pin may only be a problem if the round is hot. It is possilbe that it is a primer cup problem, with a bad lot of pimers. But, that is pretty unusual. SL1 |
January 15, 2009, 11:14 AM | #30 |
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SL1,
I am going to try your suggestion, but I still really think that Shoney probably is on the right track because of the age of the powder. I appreciate everyone's assistance and info with my issues. INGunGUy
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January 15, 2009, 05:06 PM | #31 |
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Shoney may be right about the powder, but I doubt it unless it was stored for a LONG time in a HOT place. I have a can of Unique that is at least 25 years old, and 6.2 grains of it under a 155 grain FP Ranier plated bullet gave me no trouble in my .40 S&W.
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