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Post by Quick Draw McGraw on Jun 9, 2019 22:40:11 GMT -5
So I needed a few more primers to reload with and grabbed a few out of a new pack amd mixed them in with what I was working with. I just realized that these few spares are Large Pistol Mag not Large Rifle Mag primers. Dang it! If I recall correctly, the 500 started with LPM primers, so other than a possible loss of velocity, I think I'm safe. Do you guys agree? Or should I be worried?
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JSilva
.30 Stingray
Posts: 184 
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Post by JSilva on Jun 9, 2019 23:07:26 GMT -5
punctured primers with full power loads were the reason I was told for the switch. Supposedly pistol primer cups are thinner than rifle. I’m no expert, that’s just what I can recall reading.
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Post by Quick Draw McGraw on Jun 10, 2019 2:06:41 GMT -5
Then I should be fine. They're NOT full power loads and a few popped primers arent a big deal to me.
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Post by bradshaw on Jun 10, 2019 7:29:41 GMT -5
Pierced primer
The jet of hot gas which bursts from a pierced primer acts like a cutting torch on the firing pin, sometimes to include the firing pin hole in a bolt or standing breech. Erosive action roughens the firing pin----may sharpen it to a point----which leads to more piercing.
Thin or weak primer cup
A primer cup too thin (or weak) to contain combustion burns through at the corner, causing an arc of erosion on the bolt face or standing breech.
David Bradshaw
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Post by Quick Draw McGraw on Jun 10, 2019 8:04:45 GMT -5
The jet of hot gas which burst from a pierced primer acts like a cutting torch on the firing pin, sometimes to include the firing pin hole in a bolt or standing breech. Erosive actions roughens the firing pin and may sharpen it to a point----which leads to more piercing. A primer cup too thin or weak to contain combustion burns through at the corner, causing an arc of erosion on the bolt face or standing breech. David Bradshaw Wow, that's intense! I appreciate the info, as I had no idea. Still, I only loaded 5 cartridges with pistol primers instead of rifle primers, so it's a very small amount of exposure. Also, none of what I loaded was at max loading so I don't think the primers will rupture. Still... Your knowledge and experience exceeds mine by a factor of at least ten. If you think I'm taking a dangerous risk, Mr. Bradshaw, let me know and I will heed your recommendation. I'd hate to pull all those bullets and start over, but I'm not in the mood to hurt myself. |
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Post by whitworth on Jun 10, 2019 8:58:00 GMT -5
When Peter Pi (of CorBon game) was doing some of the initial load development for the .500 Smith, he experienced sympathetic ignition test firing, meaning another round went off (that wasn’t pointed down the barrel) when it’s primer slammed into the recoil shield on recoil. This is what I was told was the impetus for using the tougher rifle primers. The .500 S&W is a big, violent round.
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Post by bradshaw on Jun 10, 2019 9:00:21 GMT -5
Quick Draw McGraw.... Dick Casull used rifle primers to ignite his .454 Casull, a very high pressure round. We used small rifle primers in the .357 Maximum for the reason, although we settled on a lower pressure ceiling.
Piercing
A heavier FIRING PIN STRIKE is necessary to crush the explosive “pellet” in a thicker PRIMER CUP. While a pieced primer doesn’t threaten the strength of a proper firearm, to continue piercing accelerates erosion. I have seen rifles, and more rarely handguns, which pierced primers. Due to the greater volume of gas and generally higher pressure of a bottleneck rifle cartridge, erosion of the rifle firing pin tends to be more aggressive.
Blanking
A weak MAINSPRING may detonate the primer, yet fail to keep combustion pressure from pushing a piece of the cup into the firing pin hole. This is called BLANKING, or PRIMER BLANKING. In fact, it is possible to blank a primer without piercing it. Blanking does not show the signature burn-through of a pierced primer.
Blown primer pocket
A blown primer pocket is a different animal. Usually caused by a PRESSURE SPIKE, or by a very high pressure dome. (An oversize FLASH HOLE between “boiler room” and primer pocket allows even normal pressure to expand the pocket.) Upon ignition, gas flows from primer, through flash hole, to comes burins power in the boiler room of the case. Powder converts from a solid into a gas as it burns, expanding to thousands of times its original volume. Thus, gas flows back into the primer pocket and----for a moment----pushes the primer out of the pocket. The primer slams against the standing breech. The case recoils as the bullet moves forward, slamming the cashed against the standing breech. This reseats the primer.
Note: a condition of loose headspace allows the cup to flatten against the standing breech, as the cup tries to spread out before recoil reseats the primer in the pocket. A revolver with ZERO headspace play, such as a Freedom Arms, does not allow the primer to escape the pocket at all. A load which shows PRIMER FLATTENING in a revolver with loose headspace may show no flattening in a Freedom Arms.
David Bradshaw
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Post by bradshaw on Jun 10, 2019 9:03:44 GMT -5
When Peter Pi (of CorBon game) was doing some of the initial load development for the .500 Smith, he experienced sympathetic ignition test firing, meaning another round went off (that wasn’t pointed down the barrel) when it’s primer slammed into the recoil shield on recoil. This is what I was told was the impetus for using the tougher rifle primers. The .500 S&W is a big, violent round. ***** Good call, Max. The combination of a heavy bullet & high velocity produces recoil in a realm all its own. David Bradshaw |
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Post by whitworth on Jun 10, 2019 9:53:54 GMT -5
Quick Draw McGraw.... Dick Casull used rifle primers to ignite his .454 Casull, a very high pressure round. We used small rifle primers in the .357 Maximum for the reason, although we settled on a lower pressure ceiling. PiercingA heavier FIRING PIN STRIKE is necessary to crush the explosive “pellet” in a thicker PRIMER CUP. While a pieced primer doesn’t threaten the strength of a proper firearm, to continue piercing accelerates erosion. I have seen rifles, and more rarely handguns, which pierced primers. Due to the greater volume of gas and generally higher pressure of a bottleneck rifle cartridge, erosion of the rifle firing pin tends to be more aggressive. BlankingA weak MAINSPRING may detonate the primer, yet fail to keep combustion pressure from pushing a piece of the cup into the firing pin hole. This is called BLANKING, or PRIMER BLANKING. In fact, it is possible to blank a primer without piercing it. Blanking does not show the signature burn-through of a pierced primer. Blown primer pocketA blown primer pocket is a different animal. Usually caused by a PRESSURE SPIKE, or by a very high pressure dome. (An oversize FLASH HOLE between “boiler room” and primer pocket allows even normal pressure to expand the pocket.) Upon ignition, gas flows from primer, through flash hole, to comes burins power in the boiler room of the case. Powder converts from a solid into a gas as it burns, expanding to thousands of times its original volume. Thus, gas flows back into the primer pocket and----for a moment----pushes the primer out of the pocket. The primer slams against the standing breech. The case recoils as the bullet moves forward, slamming the cashed against the standing breech. This reseats the primer. Note: a condition of loose headspace allows the cup to flatten against the standing breech, as the cup tries to spread out before recoil reseats the primer in the pocket. A revolver with ZERO headspace play, such as a Freedom Arms, does not allow the primer to escape the pocket at all. A load which shows PRIMER FLATTENING in a revolver with loose headspace may show no flattening in a Freedom Arms. David Bradshaw Dick told me he chose to use small rifle primers to beef up the case head region by leaving more “meat” in that area. |
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Post by Quick Draw McGraw on Jun 10, 2019 14:58:09 GMT -5
Whit, Bradshaw: Think I should pull the rounds? Or with only 5 at non-max loads is the risk not too bad? What would you guys do in my shoes?
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Post by bradshaw on Jun 10, 2019 15:20:20 GMT -5
"Dick told me he chose to use small rifle primers to beef up the case head region by leaving more “meat” in that area.”
----whitworth
*****
Max.... may well be. We had blanking with small pistol primers in the .357 Maximum, and blanking with small rifle primers----until Bil Ruger, Jr., fetched a handful of the stronger Old Army cap & ball mainsprings to put in the SRM prototypes. The heavier mainspring stopped primer blanking. As a Rocks & Dynamite man, Dick was also a methodical experimenter. Reckon he experienced some blanking along the way. Another factor, and it’s too late to ask Dick, the strength of .45 Colt brass has varied much more than .44 Mag brass over the years. To get specific, I’ve experienced early case fatigue from a couple of lots of Remington and Speer .45 Colt brass. Was some of the early .454 Casull brass made from untrimmed .45 Colt draw?
The small primer pocket may be proportionally stronger. Flash holes are the same diameter. In a bottleneck rifle case, over-pressure finds it as easy to expand a small primer pocket as a large primer pocket. This much is certain: as chamber pressure rockets upward, case life declines.
David Bradshaw
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Post by bradshaw on Jun 10, 2019 15:30:41 GMT -5
So I needed a few more primers to reload with and grabbed a few out of a new pack amd mixed them in with what I was working with. I just realized that these few spares are Large Pistol Mag not Large Rifle Mag primers. Dang it! If I recall correctly, the 500 started with LPM primers, so other than a possible loss of velocity, I think I'm safe. Do you guys agree? Or should I be worried? ***** Without more data, I’d pull the bullets. Further on you say you have just 5 rounds with LP primers. My position----if I doubt myself, I stop. It takes just one bad round to wreck a gun. On the other hand, a moderate load may hardly care whether ignition comes from a large pistol or large rifle primer. Once we reach the Red Zone, little things act BIG. David Bradshaw |
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rug480
.30 Stingray
Posts: 139
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Post by rug480 on Jun 10, 2019 16:30:44 GMT -5
I’d hate to have a 50 cent reload tear up a Smith or BFR 500 at the range, would break my heart.
I do wonder however, if the JRH can be fired from either platforms in 500 mag but is loaded with the recommended LP primers, would the same risk not be present?
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Post by whitworth on Jun 10, 2019 17:01:23 GMT -5
I’d hate to have a 50 cent reload tear up a Smith or BFR 500 at the range, would break my heart. I do wonder however, if the JRH can be fired from either platforms in 500 mag but is loaded with the recommended LP primers, would the same risk not be present? No, the problem lies with the round, and the high pressures, not the platform. |
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