RP 41 mag Autopsy

stagpanther · April 1, 2016, 09:01 AM

recently I was firing a 41 mag reload through my Henry and the case split almost symmetrically around the circumference just below the half height point. I posted pics of this on another thread in this forum category.

I was surprised to hear back from others that they had experienced the same case failure, but there was no general agreement as to why or how this was happening--and some people responded that they had never seen or experienced anything like it. So I decided to do some amateur sleuthing since I have been firing and reloading 41 mag for at least 5 years. In that time, the majority of the brass I've used has come from factory ammo, including Remington's jacketed soft point. My supply of brass is basically winchester, starline and remington.

The failure in question results from a "snapping off" of the case just below half height. I decide to examine my used used brass from several different lots. In no particular order, here is what I found:

1. I looked at my used brass that had been reloaded and fired three or more times. The majority of the cases would probably be 3 years or older, whether from factory ammo or simply new case purchases.

Of the couple of hundred or so cases I examined, none of the winchester or starline brass showed any signs on either the exterior or interior of the case of the horizontal banding that is consistent with the case failure I had. Of all the older remington brass, only one of the cases showed signs of slight banding and that was inside the case. Al cases showed some signs of "stress" in the head web, but that is normal.

2. I also happen to have a jar of freshly fired new remington 41 mag SP ammo that was used through both my blackhawk and Henry. Out of the 50 cases--12 of them had obvious signs of horizontal banding consistent with the failure I recently experienced. These "fault lines" were either on the exterior or interior of the case--and often both. These cases are headed to the trashcan immediately. Of the remaining cases that did not show any banding, there was still A "blast residue" line within the case that was fairly symmetric and stopped in the vicinity of where the fault line occurs on the other cases with banding.

Here's were the guessing begins based on the evidence above.

First, I don't think the failure has anything to do with the weapons themselves since there are no signs of abnormality with other types of brass or ammunition, even when loaded identically.

Second, I'm guessing this is more of an issue with newer remmie brass since some of my older remmie brass has been reloaded 3 or more times and does not show any of the banding typical of the recent brass (with the one exception mentioned).

In conclusion--it seems likely that Remington recently changed the formulation of their factory ammo. This might have bee to the brass, the powder, the primer--or any combination thereof. It's also possible that it's the result of ambient storage conditions.

Since I've seen a lot of cases of recent ammo of remmies--what I've noticed is that the "blast residue" inside the case seems to aggregate along a line consistent with the horizontal fault line on both the exterior and interior of the cases.

This is pure speculation on my part--but this leads me to believe that some aspect of the propellant and primer ignition characteristics internally is somehow contributing to the formation of a brittleness fault line in the recent cases.

PS Remington apparently seals their primers on their 41 mag ammo in much the same way NATO ammo is sealed.

Mauser69 · April 1, 2016, 09:27 AM

Since those once-fired cases were mixed, and you didn't mention this in your post, it seems that you do not know which specific ones were fired in the BH vs the Henry, so you have not been able to make a correlation between the 12 damaged cases and either specific gun.

I think this correlation is very important, if you can do it. I do not own a Henry, but I can tell you that it is quite easy for me to identify any fired brass that were fed through my Rossi 92 simply from the extractor marks and a slight ejection ding each one gets from the top lip of the barrel as it flips out. This ding is not really physical damage to the brass, but shows up mostly as a tiny bright spot on the mouth when the cases are standing on my reloading bench. Maybe you can carefully inspect those 50 cases to see if there are any ejector marks on the case rim or other ejection marks that the BH would not have put there?

stagpanther · April 1, 2016, 10:01 AM

Quote:

Since those once-fired cases were mixed, and you didn't mention this in your post, it seems that you do not know which specific ones were fired in the BH vs the Henry, so you have not been able to make a correlation between the 12 damaged cases and either specific gun.

I think this correlation is very important, if you can do it. I do not own a Henry, but I can tell you that it is quite easy for me to identify any fired brass that were fed through my Rossi 92 simply from the extractor marks and a slight ejection ding each one gets from the top lip of the barrel as it flips out. This ding is not really physical damage to the brass, but shows up mostly as a tiny bright spot on the mouth when the cases are standing on my reloading bench. Maybe you can carefully inspect those 50 cases to see if there are any ejector marks on the case rim or other ejection marks that the BH would not have put there?
__________________
NRA Family Life members, TSRA Life member, USAF vet and American Legion member.

I do not believe that the type of weapon it was fired through has any relevance lacking similar banding evidence from other case types fired through the same weapons--unless you perhaps have a theory you could explain?

Mauser69 · April 1, 2016, 10:50 AM

My theory is simply this:

Guessing ("I do not believe") and knowing (making a correlation) are two very different things. If there IS a correlation between a specific gun and the damage, then you must find out the true cause. If there is NOT a correlation between the two things, then you are probably safe to blame the ammo. That last point, however, seems highly unlikely to me.

I personally think that R-P pistol brass is complete shinola, barely worth it's scrap brass value. I can feel the weakness every time I resize it or seat a bullet. But I reload what I have of it anyway until it splits. However, no matter how crappy that new brass is, NOTHING about it could ever cause regular horizontal separation like you are seeing without SOMETHING ELSE ALSO BEING PART OF THE CAUSE. If you do not want to know what that cause is, then stick with your "I do not believe".

**Unclenick** · April 1, 2016, 10:53 AM

Remington has been outsourcing some brass and bullets. If you split one of the offending cases lengthwise, I expect you'll see the brass gets thicker below the separation point, which I've seen in a lot of foreign brass, for some reason, where domestic brass thickens more gradually. As a result, any stretching that occurs using full-house loads will tend to have its pressure ring located at the end of the thickness, about where you got the separation.

As to why it is separating, where domestic brass does not is a matter of speculation. I expect the base of the bullet is near that same location when it is seated, so it may be the double-stress of being expanded by the bullet, then stretched on firing in the same region that is part of the problem. Or it may just be poor quality without the right number or right timing of annealing steps done during the stages of drawing the brass. I would just buy Starline or other known good brass to avoid the issue. You could probably load light practice loads in this stuff without problems.

stagpanther · April 1, 2016, 11:23 AM

Quote:

My theory is simply this:

Guessing ("I do not believe") and knowing (making a correlation) are two very different things. If there IS a correlation between a specific gun and the damage, then you must find out the true cause. If there is NOT a correlation between the two things, then you are probably safe to blame the ammo. That last point, however, seems highly unlikely to me.

I personally think that R-P pistol brass is complete shinola, barely worth it's scrap brass value. I can feel the weakness every time I resize it or seat a bullet. But I reload what I have of it anyway until it splits. However, no matter how crappy that new brass is, NOTHING about it could ever cause regular horizontal separation like you are seeing without SOMETHING ELSE ALSO BEING PART OF THE CAUSE. If you do not want to know what that cause is, then stick with your "I do not believe".
__________________
NRA Family Life members, TSRA Life member, USAF vet and American Legion member.

OK. For each case the odds are 100% that it was fired from either the blackhawk or Henry--so what should I be looking for in either instance? The recently fired new stuff has already been cleaned and tumbled--but not resized or de-primed. There are no signs of abnormal (meaning .002+) stretch or head expansion in any of the cases, nor any knicks, dents or scratches. All primers look normal.

Mauser69 · April 1, 2016, 12:04 PM

Quote:

OK. For each case the odds are 100% that it was fired from either the blackhawk or Henry--so what should I be looking for in either instance? The recently fired new stuff has already been cleaned and tumbled--but not resized or de-primed. There are no signs of abnormal (meaning .002+) stretch or head expansion in any of the cases, nor any knicks, dents or scratches. All primers look normal.

At this stage, you are only looking for any identifying marks on each case that might tell you which gun it was fired in so that you can see if there IS a correlation. It is most likely that you will find marks that can identify the lever gun, but not the BH.

There are not many things in a BH that can cause an identifiable mark on the brass when fired. About the only thing that MIGHT show up is on the primer or case head from rough machining on the face of the frame around the firing pin. The lever gun, however, is totally different. Not only does it push the loaded shells around a lot, potentially leaving marks in various places on the brass, but it has an extractor that both slips over the case rim when the bolt closes, and then must grip under the rim to pull out the fired shell. Finally, something causes the shell to fly up and out of the chamber as the bolt is pulled back, and if the lip touches anything during that process, it can leave a tiny identifying mark (usually in the soot, but that is already gone for your cleaned brass). The most likely place for you to see a difference in shells that came from one gun or the other is either in the indentations on the primer or tiny nicks on the case rim edge or top.

Look at ALL the fired brass, not just the 12 damaged cases - that is the only way you will be able to see if some of the cases have any specifically identifying marks on them. Of course, the more simple test now would be to just fire another box of the same ammo, half in each gun, and keep the new brass segregated until you inspect it all for signs of case damage again. the ONLY way you will know for sure that this problem is not at least partially caused by one of your guns is if you can positively identify the same brass damage in cases that you KNOW were fired only one time, and the damage shows up in fired cases from both guns.

stagpanther · April 1, 2016, 01:18 PM

Quote:

Of course, the more simple test now would be to just fire another box of the same ammo, half in each gun, and keep the new brass segregated until you inspect it all for signs of case damage again.

LOL--Even before you posted this I already decided that's exactly whet I'm going to do. : ) I might get lucky and get the same batch at the same GS.

James K · April 1, 2016, 03:31 PM

You don't seem to want to consider the possibility, but I have little doubt that the problem is excess headspace. Whether a given case tears apart or simply stretches may depend on the case and how it was made, and whether a weak point was created. But the case came apart because the back end was allowed to move back while the front end was being held in place by internal pressure. And that is the result of excess headspace.

It is possible, but unlikely, that one lot of brass has extra thin rims, which would create the same condition, but I would still check the rifle.

Jim

stagpanther · April 1, 2016, 04:07 PM

Quote:

You don't seem to want to consider the possibility, but I have little doubt that the problem is excess headspace. Whether a given case tears apart or simply stretches may depend on the case and how it was made, and whether a weak point was created. But the case came apart because the back end was allowed to move back while the front end was being held in place by internal pressure. And that is the result of excess headspace.

It is possible, but unlikely, that one lot of brass has extra thin rims, which would create the same condition, but I would still check the rifle.

Jim
__________________
Jim K

I will check the headspace on my Henry best as I can--just not familiar with a technique that really gives meaningful results on a lever gun.

stagpanther · April 1, 2016, 06:17 PM

I just checked the headspace in the Henry by the "scotch tape layer" method. It's a bit difficult to actually gauge the resistance at bolt close because the lever has a catch of some sort that "snaps" the lever close. The lever showed notable resistance at 3 layers--and would not close at all with 4 layers.

addendum--the resistence started at .009 +/- and the bolt would not close at all at .012

Jeffm004 · April 2, 2016, 01:12 PM

I am also guessing. But it is fun. What if it is fatigue due to the brass having slightly different support in the different firearms causing fatigue over different firings in different guns, That might explain the consistent fail point and viewed discontinuity.

You might try the same brass in two diff guns, measure diameter at the fail point.

Or new brass is being made just a tad thinner. I might sen the case to the manufacturer and ask.

stagpanther · April 2, 2016, 01:20 PM

The real solution is what I just did--I ordered 500 new cases from starline. Never once have had a problem with their brass in any hand load in any caliber I've ever done so far. : ) Why mess with success?

stubbicatt · April 2, 2016, 03:38 PM

stag panther, I really enjoy following your reasoning. Other contributors, the respectful and insightful responses makes being a member of this forum a real joy.

OP, I think you did the right thing getting a known quality brass from Starline.

stagpanther · April 2, 2016, 05:37 PM

Quote:

stag panther, I really enjoy following your reasoning. Other contributors, the respectful and insightful responses makes being a member of this forum a real joy.

OP, I think you did the right thing getting a known quality brass from Starline.

I am the OP--but thanx for the compliment anyways. : ) Nice to think there's a method to my madness. LOL

Real Gun · April 3, 2016, 07:27 AM

I expect stronger brass will just cover up the true cause. I still consider R.P brass as suspect because of the thin walled brass I find in 38 Special. Most of the reloading for my other calibers was seeded by 500 pieces of new Starline, so I may be shielded from problems with other head stamps. I bought some commercial ammo for 41 Magnum but haven't used it. It is rare, expensive, and reserved for SD/hunting.

stagpanther · April 3, 2016, 07:49 AM

Quote:

I expect stronger brass will just cover up the true cause. I still consider R.P brass as suspect because of the thin walled brass I find in 38 Special. Most of the reloading for my other calibers was seeded by 500 pieces of new Starline, so I may be shielded from problems with other head stamps. I bought some commercial ammo for 41 Magnum but haven't used it. It is rare, expensive, and reserved for SD/hunting.
__________________
Not an expert, just a reporter.

There's no doubt in my mind that the remmie brass contributes to the problem.

This experience has caused me to take a very close look at the various types of dies and to take measurements every step of the way through the process of reloading, and it has revealed some interesting things to me.

What I've found is that in general--any load like the 41 (including the 44 mag) which is fairly powerful will undergo quite a bit of brass expansion and contraction--not just from fire-forming but also in the process of reloading. A good strong crimp is essential for even ignition, safety in retaining the bullet seating and consistency in mouth tension.

A powerful crimp on the case mouth often induces a downward force and compression on all case designs. I'm not sure what the reasons are--but this seems to have more effect on my 41 mag loads than my 44 mag loads.

I was recently tipped off by the admin of the rossi forum that he had induced Lee to make a custom run of 41 collet style crimps for the 41 mag--which I just ordered. This features the lateral squeeze as found in their bottleneck cartridge dies and should eliminate any downward pressure on crimp (though I strongly suspect the bullet has a tendency to "slide" a bit as the case lip rolls over the cannelure edge). This is a "over-run" production, so I don't know how long they will be available. you can find it here: http://leeprecision.com/41-magnum-cu...crimp-die.html

Tom Matiska · April 3, 2016, 11:40 AM

How fast of a powder is involved? Faster powders are more likely to cause the case to expand and grab the chamber wall before setback occurs..... makes little head space problem cause big stretching.

EDIT: I see from a duplicate thread you're using H110, so fast powder shouldn't be a problem.... but Hodgdon's online data maxes out a 22.0 so your book that shows 22.7 may be a little too warm.

stagpanther · April 3, 2016, 01:01 PM

Quote:

How fast of a powder is involved? Faster powders are more likely to cause the case to expand and grab the chamber wall before setback occurs..... makes little head space problem cause big stretching.

EDIT: I see from a duplicate thread you're using H110, so fast powder shouldn't be a problem.... but Hodgdon's online data maxes out a 22.0 so your book that shows 22.7 may be a little too warm.
__________________

Could be--it's been one of my better performers in my blackhawk and it is in Hornady's 210 gr xtp manual at the top end of their load recommendation. Henry folks told me their 41 mag is the essentially the same rifle as their 44 mag except the different bore and bolt and should hold up to 44 mag levels.

briandg · April 4, 2016, 11:16 PM

No cannelures, or unusual marks? No tiny yet noticeable grooves in any chamber or cylinder? Look VERY CAREFULLY. If you have a flaw in the brass, your dies will stretch and compress the case several times during loading. Weak brass, a condition that weakens that area, and several loadings could cause those fractures, especially if the Henry is slightly oversized.

I suspect a combination. I suggest that you pick a few of the cases that you suspect, and resize and expand them dozens of times to see if they fail. That will at least give you some information.

April 1, 2016, 09:01 AM	#1
stagpanther Senior Member Join Date: March 2, 2014 Posts: 11,772	RP 41 mag Autopsy recently I was firing a 41 mag reload through my Henry and the case split almost symmetrically around the circumference just below the half height point. I posted pics of this on another thread in this forum category. I was surprised to hear back from others that they had experienced the same case failure, but there was no general agreement as to why or how this was happening--and some people responded that they had never seen or experienced anything like it. So I decided to do some amateur sleuthing since I have been firing and reloading 41 mag for at least 5 years. In that time, the majority of the brass I've used has come from factory ammo, including Remington's jacketed soft point. My supply of brass is basically winchester, starline and remington. The failure in question results from a "snapping off" of the case just below half height. I decide to examine my used used brass from several different lots. In no particular order, here is what I found: 1. I looked at my used brass that had been reloaded and fired three or more times. The majority of the cases would probably be 3 years or older, whether from factory ammo or simply new case purchases. Of the couple of hundred or so cases I examined, none of the winchester or starline brass showed any signs on either the exterior or interior of the case of the horizontal banding that is consistent with the case failure I had. Of all the older remington brass, only one of the cases showed signs of slight banding and that was inside the case. Al cases showed some signs of "stress" in the head web, but that is normal. 2. I also happen to have a jar of freshly fired new remington 41 mag SP ammo that was used through both my blackhawk and Henry. Out of the 50 cases--12 of them had obvious signs of horizontal banding consistent with the failure I recently experienced. These "fault lines" were either on the exterior or interior of the case--and often both. These cases are headed to the trashcan immediately. Of the remaining cases that did not show any banding, there was still A "blast residue" line within the case that was fairly symmetric and stopped in the vicinity of where the fault line occurs on the other cases with banding. Here's were the guessing begins based on the evidence above. First, I don't think the failure has anything to do with the weapons themselves since there are no signs of abnormality with other types of brass or ammunition, even when loaded identically. Second, I'm guessing this is more of an issue with newer remmie brass since some of my older remmie brass has been reloaded 3 or more times and does not show any of the banding typical of the recent brass (with the one exception mentioned). In conclusion--it seems likely that Remington recently changed the formulation of their factory ammo. This might have bee to the brass, the powder, the primer--or any combination thereof. It's also possible that it's the result of ambient storage conditions. Since I've seen a lot of cases of recent ammo of remmies--what I've noticed is that the "blast residue" inside the case seems to aggregate along a line consistent with the horizontal fault line on both the exterior and interior of the cases. This is pure speculation on my part--but this leads me to believe that some aspect of the propellant and primer ignition characteristics internally is somehow contributing to the formation of a brittleness fault line in the recent cases. PS Remington apparently seals their primers on their 41 mag ammo in much the same way NATO ammo is sealed. __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!* Last edited by stagpanther; April 1, 2016 at 09:07 AM.

April 1, 2016, 10:53 AM	#5
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	Remington has been outsourcing some brass and bullets. If you split one of the offending cases lengthwise, I expect you'll see the brass gets thicker below the separation point, which I've seen in a lot of foreign brass, for some reason, where domestic brass thickens more gradually. As a result, any stretching that occurs using full-house loads will tend to have its pressure ring located at the end of the thickness, about where you got the separation. As to why it is separating, where domestic brass does not is a matter of speculation. I expect the base of the bullet is near that same location when it is seated, so it may be the double-stress of being expanded by the bullet, then stretched on firing in the same region that is part of the problem. Or it may just be poor quality without the right number or right timing of annealing steps done during the stages of drawing the brass. I would just buy Starline or other known good brass to avoid the issue. You could probably load light practice loads in this stuff without problems. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

April 1, 2016, 06:17 PM	#11
stagpanther Senior Member Join Date: March 2, 2014 Posts: 11,772	I just checked the headspace in the Henry by the "scotch tape layer" method. It's a bit difficult to actually gauge the resistance at bolt close because the lever has a catch of some sort that "snaps" the lever close. The lever showed notable resistance at 3 layers--and would not close at all with 4 layers. addendum--the resistence started at .009 +/- and the bolt would not close at all at .012 __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!* Last edited by stagpanther; April 2, 2016 at 05:39 PM.

April 2, 2016, 01:12 PM	#12
Jeffm004 Senior Member Join Date: August 22, 2013 Location: SW Ohio Posts: 255	I am also guessing. But it is fun. What if it is fatigue due to the brass having slightly different support in the different firearms causing fatigue over different firings in different guns, That might explain the consistent fail point and viewed discontinuity. You might try the same brass in two diff guns, measure diameter at the fail point. Or new brass is being made just a tad thinner. I might sen the case to the manufacturer and ask. Last edited by Jeffm004; April 2, 2016 at 01:25 PM.

April 2, 2016, 01:20 PM	#13
stagpanther Senior Member Join Date: March 2, 2014 Posts: 11,772	The real solution is what I just did--I ordered 500 new cases from starline. Never once have had a problem with their brass in any hand load in any caliber I've ever done so far. : ) Why mess with success? __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!*

April 1, 2016, 09:27 AM	#2
Mauser69 Senior Member Join Date: January 27, 2014 Location: New Mexico Posts: 204	Since those once-fired cases were mixed, and you didn't mention this in your post, it seems that you do not know which specific ones were fired in the BH vs the Henry, so you have not been able to make a correlation between the 12 damaged cases and either specific gun. I think this correlation is very important, if you can do it. I do not own a Henry, but I can tell you that it is quite easy for me to identify any fired brass that were fed through my Rossi 92 simply from the extractor marks and a slight ejection ding each one gets from the top lip of the barrel as it flips out. This ding is not really physical damage to the brass, but shows up mostly as a tiny bright spot on the mouth when the cases are standing on my reloading bench. Maybe you can carefully inspect those 50 cases to see if there are any ejector marks on the case rim or other ejection marks that the BH would not have put there? __________________ NRA Family Life members, TSRA Life member, USAF vet and American Legion member.

April 1, 2016, 10:50 AM	#4
Mauser69 Senior Member Join Date: January 27, 2014 Location: New Mexico Posts: 204	My theory is simply this: Guessing ("I do not believe") and knowing (making a correlation) are two very different things. If there IS a correlation between a specific gun and the damage, then you must find out the true cause. If there is NOT a correlation between the two things, then you are probably safe to blame the ammo. That last point, however, seems highly unlikely to me. I personally think that R-P pistol brass is complete shinola, barely worth it's scrap brass value. I can feel the weakness every time I resize it or seat a bullet. But I reload what I have of it anyway until it splits. However, no matter how crappy that new brass is, NOTHING about it could ever cause regular horizontal separation like you are seeing without SOMETHING ELSE ALSO BEING PART OF THE CAUSE. If you do not want to know what that cause is, then stick with your "I do not believe". __________________ NRA Family Life members, TSRA Life member, USAF vet and American Legion member.

April 1, 2016, 03:31 PM	#9
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	You don't seem to want to consider the possibility, but I have little doubt that the problem is excess headspace. Whether a given case tears apart or simply stretches may depend on the case and how it was made, and whether a weak point was created. But the case came apart because the back end was allowed to move back while the front end was being held in place by internal pressure. And that is the result of excess headspace. It is possible, but unlikely, that one lot of brass has extra thin rims, which would create the same condition, but I would still check the rifle. Jim

April 2, 2016, 03:38 PM	#14
stubbicatt Senior Member Join Date: September 15, 2007 Posts: 1,707	stag panther, I really enjoy following your reasoning. Other contributors, the respectful and insightful responses makes being a member of this forum a real joy. OP, I think you did the right thing getting a known quality brass from Starline.

April 3, 2016, 07:27 AM	#16
Real Gun Senior Member Join Date: May 19, 2004 Location: SC Posts: 2,743	I expect stronger brass will just cover up the true cause. I still consider R.P brass as suspect because of the thin walled brass I find in 38 Special. Most of the reloading for my other calibers was seeded by 500 pieces of new Starline, so I may be shielded from problems with other head stamps. I bought some commercial ammo for 41 Magnum but haven't used it. It is rare, expensive, and reserved for SD/hunting. __________________ Not an expert, just a reporter.

April 3, 2016, 11:40 AM	#18
Tom Matiska Senior Member Join Date: April 12, 2000 Location: Wilkes-Barre, Pa Posts: 1,029	How fast of a powder is involved? Faster powders are more likely to cause the case to expand and grab the chamber wall before setback occurs..... makes little head space problem cause big stretching. EDIT: I see from a duplicate thread you're using H110, so fast powder shouldn't be a problem.... but Hodgdon's online data maxes out a 22.0 so your book that shows 22.7 may be a little too warm. __________________ A gun is like a parachute... when you need one you usually need it pretty bad... Last edited by Tom Matiska; April 3, 2016 at 12:15 PM.

April 4, 2016, 11:16 PM	#20
briandg Senior Member Join Date: May 4, 2010 Posts: 5,468	No cannelures, or unusual marks? No tiny yet noticeable grooves in any chamber or cylinder? Look VERY CAREFULLY. If you have a flaw in the brass, your dies will stretch and compress the case several times during loading. Weak brass, a condition that weakens that area, and several loadings could cause those fractures, especially if the Henry is slightly oversized. I suspect a combination. I suggest that you pick a few of the cases that you suspect, and resize and expand them dozens of times to see if they fail. That will at least give you some information. __________________ None.