blown primer with "safe" load--help!! - Page 2

**Unclenick** · December 24, 2011, 05:08 PM

Soonershooter,

It would be the neck OD over top of a loaded bullet that would be the critical dimension. FYI, on the board if you use square brackets to enclose the word “code”, followed by square brackets enclosing “/code”, anything you type in between the bracketed pairs characters will be put in a little window that lets you keep any extra spaces you type. That lets you line up columns.

Example,

[code]text here[/code].

With your text that let’s me align as follows:

Code:

                                                   New Case       Damaged Case
Primer Pocket                                       .206             .225
Rim Diameter                                        .469             .485
Neck Outside Diameter                               .309             .316
Neck Outside Diameter after Bullets Pulled          .310             .314

Inside Diameter of .308 case necked to 7mm after bullets were pulled .284
Outside Diameter of 7mm-08 case after it was resized                 .309
Inside Diameter of 7mm-08 case after it was resized                  .279

Date the cartridges were loaded:                           Sept. 13, 2002

Slamfire,

I don't doubt the 7mm-'08 accounts. You can't run a .316" case mouth into .316" chamber mouth safely. Half a thousandth is the normal minimum clearance, though I gather some of the BR guys push that to tighter numbers. I know I wouldn't. As I commented in my second post, all it would take is a small remaining burr on the mouth to cause it to become a crush fit. In posting the chamber dimensions, my purpose was just to point out the chamber dimensions because the case minimum is a half thousandth larger than the cartridge maximum, which is what I think 243xb was referring to in his post preceding the numbers I put up.

The SAAMI tolerance on the chamber is +0.002" over those minimums, so unless the chamber was cut with a worn and overly resharpened reamer (does happen sometimes) it is not likely to be quite as small as dead minimum. In this case Soonershooter said he fired 30-40 rounds of the same loads a few year's previously without incident, so my expectation from that is he doesn't have a minimum chamber. If it is too close to tell indirectly form cases, a chamber cast or lead slug in the neck will be needed to determine the dimension for certain.

On Hatcher, it is good to know why you consider his reporting a cover-up. I think proving one is difficult unless you can demonstrate Hatcher’s timeline is an outright fabrication. I say that because, with the information laid out as Hatcher provides it, at least up through the end of the 1921 National Matches, and not including things we know today that nobody knew back then, I believe I would have been lead to the same conclusion he made at that point in history.

The timeline matters because is it says Whelen’s grease pressure tests preceded the tinned bullet problem entirely. Whether Whelen’s results reflect accurate pressure numbers or not is moot for the purposes of Hatcher’s theorizing because the squirrely nature of copper crushers was not clearly proven until the mid 1960’s, and the military continued believing in them for another 30 years after that. Hatcher’s reasoning would be unchanged if he trusted the veracity of crusher numbers in 1921.

Naramore himself says the tinned bullet ammunition would fire properly when first loaded. He doesn't define the upper limit of "first loaded" in days, weeks, months, or years, and would likely not have had the data necessary to do so, but at the end of the 1921 National Matches, the “tin can” ammo would still have been less than a year old. It shot several records, suggesting it was at least not wildly irregular. When Naramore publishes 16 years later, even FA 20 and FA 22 would have been a good deal harder to pull from their cases than when fresh. I have no idea how much harder the tinned bullets were sticking by then.

Hatcher had fresh “tin can” ammunition himself before the 1921 matches, and measured the hard bullet pull and queried Whelen about it. Whelen responded that it still fired fine (in a dry gun) and Hatcher then fired it (in a dry gun) to verify Whelen's assertion. He found that it did behave a Whelen said at that point in time.

Lastly, Hatcher reports grease was found to have been used by the shooters of all the guns that blew up at the 1921 National Matches. So, in 1921 he has:

Whelen’s crusher tests showing grease increased pressure in FA 20 ammo, and no reason to mistrust that result at the time.
Validation that fresh tinned bullet ammo fired properly in dry chambers.
All guns damaged at the 1921 Nationals had proven to have had grease used by their shooters.
Several records were set at the 1921 Nationals, giving the impression that FA 21 performed with good consistency when used according to the rules.

What Hatcher concludes, when you combine the last three complete paragraphs on page 341 of his Notebook, is the high start pressure caused by the tinned bullets being, as he puts it, “practically soldered in” increased the starting pressure and powder burn rate, and that combined with relatively incompressible grease surrounding the neck to prevent release of the bullet in time to avoid unsafe pressure. I think that was a reasonable hypothesis at that point in history.

In favor of a cover-up, the first thing we have is the later destruction of a few ‘03’s firing FA 21. Unfortunately, to prove cover-up you have to know that Hatcher knew the bullets were not greased when fired in those instances. If there was grease used, he still would think it supported his 1921 conclusion.

The second thing we have is the Ordnance Department destroying all the remaining FA 21 they could. You could claim this means they knew it was dangerous by itself and wanted to cover that up, but it could also be explained if they simply bought into Hatcher’s conclusion and knew they couldn’t stop everyone from greasing it. I note Hatcher refers to FA 21 as “experimental”. In today’s litigious society nobody would consider issuing something “experimental” to the shooting public, but that was a different day. Perhaps the “experimental” classification caused the O.D. to dispose of it as a failed experiment, but I have no way to know.

The third and most damning thing you have is simply that there had been no clearly reported grease-related blow-up problems when no tin was present on bullets, either before or after, when surely some people were greasing. Otherwise, where did the shooters using grease in 1921 come from, and why didn’t their guns blow up in 1920 before the no-grease rule was made? Moreover, even if you believe Whelen’s pressure numbers, a gun should withstand greasing of a conventional round, especially if it’s just applied to the bullet.

Against the cover-up, you have to ask why Hatcher published information about blown up guns and Ordnance Department disposal that a clever analyst could use to expose the cover-up? If you believe the tinning of the bullets alone was responsible, then either the analysis is inadequate or the cover-up is. I don’t see a reason to favor the latter over the former when you consider the added complexity of collusion violates Occam’s razor. Because we didn’t have a litigious and lawsuit-happy society in 1921, they may have considered the risk was well-enough established at the Nationals. They paid for the ammo, they paid for the guns. Nobody was seriously hurt, so nothing needed either covering up or broadcasting. Absent more documentation, you'd probably have to be there to know one way or the other.

Nick

F. Guffey · December 25, 2011, 06:16 PM

http://www.milsurps.com/sea_stories/end_of_an_era.pdf

http://www.americanrifleman.org/arti...mp-perry-1921/

Up until now this thread has been about an event, when it comes to stories I like the one about people and events that defy explanation. Sergeant John W. Adkins of the Marines and George R. Farr ‘Dad’ were participants, one shooter had all the whistle and bells, the other had to settle for a rifle issued the morning of the shoot, one had all the advantages of time, the other with old eyes of 62 ran out of daylight, one of them shot ‘match’ issued ammo, the other shot the good stuff? George Farr as a custom was supposed to receive the rifle he shot, that mistake was corrected later.

Shooting with grease? I suppose the 1921 match was shot before the physics of a fluid was known, with time running out nothing is said about George Farr running out of time because he grease his bullets, chamber and or case OR all three.

I am a fan of having nothing between the case and chamber but air, there is nothing more effective than 100% contact, and I am a fan of cutting down on all that case travel.

F. Guffey

December 24, 2011, 05:08 PM	#26
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,060	Soonershooter, It would be the neck OD over top of a loaded bullet that would be the critical dimension. FYI, on the board if you use square brackets to enclose the word “code”, followed by square brackets enclosing “/code”, anything you type in between the bracketed pairs characters will be put in a little window that lets you keep any extra spaces you type. That lets you line up columns. Example, [code]text here[/code]. With your text that let’s me align as follows: Code: New Case Damaged Case Primer Pocket .206 .225 Rim Diameter .469 .485 Neck Outside Diameter .309 .316 Neck Outside Diameter after Bullets Pulled .310 .314 Inside Diameter of .308 case necked to 7mm after bullets were pulled .284 Outside Diameter of 7mm-08 case after it was resized .309 Inside Diameter of 7mm-08 case after it was resized .279 Date the cartridges were loaded: Sept. 13, 2002 Slamfire, I don't doubt the 7mm-'08 accounts. You can't run a .316" case mouth into .316" chamber mouth safely. Half a thousandth is the normal minimum clearance, though I gather some of the BR guys push that to tighter numbers. I know I wouldn't. As I commented in my second post, all it would take is a small remaining burr on the mouth to cause it to become a crush fit. In posting the chamber dimensions, my purpose was just to point out the chamber dimensions because the case minimum is a half thousandth larger than the cartridge maximum, which is what I think 243xb was referring to in his post preceding the numbers I put up. The SAAMI tolerance on the chamber is +0.002" over those minimums, so unless the chamber was cut with a worn and overly resharpened reamer (does happen sometimes) it is not likely to be quite as small as dead minimum. In this case Soonershooter said he fired 30-40 rounds of the same loads a few year's previously without incident, so my expectation from that is he doesn't have a minimum chamber. If it is too close to tell indirectly form cases, a chamber cast or lead slug in the neck will be needed to determine the dimension for certain. On Hatcher, it is good to know why you consider his reporting a cover-up. I think proving one is difficult unless you can demonstrate Hatcher’s timeline is an outright fabrication. I say that because, with the information laid out as Hatcher provides it, at least up through the end of the 1921 National Matches, and not including things we know today that nobody knew back then, I believe I would have been lead to the same conclusion he made at that point in history. The timeline matters because is it says Whelen’s grease pressure tests preceded the tinned bullet problem entirely. Whether Whelen’s results reflect accurate pressure numbers or not is moot for the purposes of Hatcher’s theorizing because the squirrely nature of copper crushers was not clearly proven until the mid 1960’s, and the military continued believing in them for another 30 years after that. Hatcher’s reasoning would be unchanged if he trusted the veracity of crusher numbers in 1921. Naramore himself says the tinned bullet ammunition would fire properly when first loaded. He doesn't define the upper limit of "first loaded" in days, weeks, months, or years, and would likely not have had the data necessary to do so, but at the end of the 1921 National Matches, the “tin can” ammo would still have been less than a year old. It shot several records, suggesting it was at least not wildly irregular. When Naramore publishes 16 years later, even FA 20 and FA 22 would have been a good deal harder to pull from their cases than when fresh. I have no idea how much harder the tinned bullets were sticking by then. Hatcher had fresh “tin can” ammunition himself before the 1921 matches, and measured the hard bullet pull and queried Whelen about it. Whelen responded that it still fired fine (in a dry gun) and Hatcher then fired it (in a dry gun) to verify Whelen's assertion. He found that it did behave a Whelen said at that point in time. Lastly, Hatcher reports grease was found to have been used by the shooters of all the guns that blew up at the 1921 National Matches. So, in 1921 he has: Whelen’s crusher tests showing grease increased pressure in FA 20 ammo, and no reason to mistrust that result at the time. Validation that fresh tinned bullet ammo fired properly in dry chambers. All guns damaged at the 1921 Nationals had proven to have had grease used by their shooters. Several records were set at the 1921 Nationals, giving the impression that FA 21 performed with good consistency when used according to the rules. What Hatcher concludes, when you combine the last three complete paragraphs on page 341 of his Notebook, is the high start pressure caused by the tinned bullets being, as he puts it, “practically soldered in” increased the starting pressure and powder burn rate, and that combined with relatively incompressible grease surrounding the neck to prevent release of the bullet in time to avoid unsafe pressure. I think that was a reasonable hypothesis at that point in history. In favor of a cover-up, the first thing we have is the later destruction of a few ‘03’s firing FA 21. Unfortunately, to prove cover-up you have to know that Hatcher knew the bullets were not greased when fired in those instances. If there was grease used, he still would think it supported his 1921 conclusion. The second thing we have is the Ordnance Department destroying all the remaining FA 21 they could. You could claim this means they knew it was dangerous by itself and wanted to cover that up, but it could also be explained if they simply bought into Hatcher’s conclusion and knew they couldn’t stop everyone from greasing it. I note Hatcher refers to FA 21 as “experimental”. In today’s litigious society nobody would consider issuing something “experimental” to the shooting public, but that was a different day. Perhaps the “experimental” classification caused the O.D. to dispose of it as a failed experiment, but I have no way to know. The third and most damning thing you have is simply that there had been no clearly reported grease-related blow-up problems when no tin was present on bullets, either before or after, when surely some people were greasing. Otherwise, where did the shooters using grease in 1921 come from, and why didn’t their guns blow up in 1920 before the no-grease rule was made? Moreover, even if you believe Whelen’s pressure numbers, a gun should withstand greasing of a conventional round, especially if it’s just applied to the bullet. Against the cover-up, you have to ask why Hatcher published information about blown up guns and Ordnance Department disposal that a clever analyst could use to expose the cover-up? If you believe the tinning of the bullets alone was responsible, then either the analysis is inadequate or the cover-up is. I don’t see a reason to favor the latter over the former when you consider the added complexity of collusion violates Occam’s razor. Because we didn’t have a litigious and lawsuit-happy society in 1921, they may have considered the risk was well-enough established at the Nationals. They paid for the ammo, they paid for the guns. Nobody was seriously hurt, so nothing needed either covering up or broadcasting. Absent more documentation, you'd probably have to be there to know one way or the other. Nick __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

December 25, 2011, 06:16 PM	#27
F. Guffey Senior Member Join Date: July 18, 2008 Posts: 7,249	http://www.milsurps.com/sea_stories/end_of_an_era.pdf http://www.americanrifleman.org/arti...mp-perry-1921/ Up until now this thread has been about an event, when it comes to stories I like the one about people and events that defy explanation. Sergeant John W. Adkins of the Marines and George R. Farr ‘Dad’ were participants, one shooter had all the whistle and bells, the other had to settle for a rifle issued the morning of the shoot, one had all the advantages of time, the other with old eyes of 62 ran out of daylight, one of them shot ‘match’ issued ammo, the other shot the good stuff? George Farr as a custom was supposed to receive the rifle he shot, that mistake was corrected later. Shooting with grease? I suppose the 1921 match was shot before the physics of a fluid was known, with time running out nothing is said about George Farr running out of time because he grease his bullets, chamber and or case OR all three. I am a fan of having nothing between the case and chamber but air, there is nothing more effective than 100% contact, and I am a fan of cutting down on all that case travel. F. Guffey