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OLD IMR powder
PA Shootist
Member Posts: 691 ✭✭✭
Looking for a soft-recoiling practice load, I recently reloaded some 6.5x55 Swedish for my grandson's sporterized rifle. I was using a starting load of IMR 4320, from a Lyman manual, with 120 gr Speer spitzer bullets, PMC once-fired cases of unknown age, and W-W standard large rifle primers. The bore of this rifle is in good condition and slugs at .265", and shoots well, with no high pressure indications, with various factory loads. In this case, the primers were flattened and cratered, and 2 cases showed incipient head separation about a half inch ahead of rim, in 5 shots. I ceased at that point and pulled the balance.
This powder was old, in a one-pound can, but kept in good storage, appeared fine, and smelled normal (the glycerine smell familiar to IMR powders). My best estimate of age might be 35 years (?!); I used to reload with 4320 frequently in a couple calibers. I threw this can away, because it created high pressures at a starting load, all else seeming normal. Yes, I did double-check my scale, against known weights and a second scale. All charges were weighed, and each cartridge visually inspected through the process. Bullets were seated well short of the rifling. Is there a practical calendar limit to the age of gunpowders? Is there any good way to tell if there is deterioration? I have read about discoloration, reddish appearance, bad smells, etc.
This powder was old, in a one-pound can, but kept in good storage, appeared fine, and smelled normal (the glycerine smell familiar to IMR powders). My best estimate of age might be 35 years (?!); I used to reload with 4320 frequently in a couple calibers. I threw this can away, because it created high pressures at a starting load, all else seeming normal. Yes, I did double-check my scale, against known weights and a second scale. All charges were weighed, and each cartridge visually inspected through the process. Bullets were seated well short of the rifling. Is there a practical calendar limit to the age of gunpowders? Is there any good way to tell if there is deterioration? I have read about discoloration, reddish appearance, bad smells, etc.
Comments
EDIT You did not state what your manual listed but my manuals show MAX LOADS 41.0 grains were you below That. [?][?][?]
I bought 8 LBs of IMR4320 a few years back and called Sierra concerning loads.
The first thing he told me was one of the staff just blew up a 96 Swede with IMR 4320 using the starting load.
No BS, I recommend what Sierra recommended.
Do not use IMR4320 in a 6.5 Swede load.
That does not mean it is not useful in other calibers however, I sold the powder as it seems sensitive and unforgiving when its boundaries are approached where as powders like 4895 are so forgiving.
IMO (and Sierra's)
Wulfmann
"Fools learn from their own mistakes. I learn from the mistakes of others"
Otto von Bismarck
"I recently reloaded some 6.5x55 Swedish..."
"In this case, the primers were flattened and cratered, and 2 cases showed incipient head separation about a half inch ahead of rim, in 5 shots."
Incipient case head separation is caused by a problem with headspace. This can show up because the chamber has a generous headspace OR because the shoulders of your cases have been set back. We just got through with a similar discussion.
The firing pin pushes the case forward into the neck of the chamber where the pressure builds forcing the case to grip the walls of the chamber. As pressure rises, the case head is forced back against the bolt face, stretching the case, causing the case to show a bright ring where it has stretched. The primer was pushed out of the primer pocket as well and was smashed against the bolt face showing flattening and cratering because the primer was forced into the firing pin hole. A straightened paper clip with a small tip bent into it can test for the separation by scraping the inside of the case feeling for the indention.
I'd check your cases and your chamber for proper headspace.
"Is there a practical calendar limit to the age of gunpowders?"
Not really, although age can be a contributing factor. We all have experience with old powders that have continued to perform for decades. The calendar doesn't necessarily control the deterioration, the storage conditions usually do.
IMR-4320 is too fast to use in the 6.5 x 55 Swede and I don't care what the manuals state. You might get away with some loads in some cartridges under some conditions but in the general methodology of reloading where burn rates are compared to case volume and bullet selected, this powder is too fast. You need a slower powder that will fill the case more completely while operating at a lower pressure.
"The first thing he told me was one of the staff just blew up a 96 Swede with IMR 4320 using the starting load."
No offense to you at all but this is an unconscionable statement for a Sierra employee to make to someone that was asking for guidance. He should have been fired. That's all I'll say.
Best.
"The first thing he told me was one of the staff just blew up a 96 Swede with IMR 4320 using the starting load."
No offense to you at all but this is an unconscionable statement for a Sierra employee to make to someone that was asking for guidance. He should have been fired. That's all I'll say.
Best.
So, let me see if I have this straight.
You say one should not use IMR4320 in 6.5 Swede because it is too fast.
The employee at Sierra recounts a coworkers experience that exemplifies your statement but considering the dangerous example it was, should not have alerted me???
This when I called because my experience in 308 caused concern because pressure signs developed in what should have been "safe" loads.
No offense, but that information from Sierra was exactly what should have been relayed and I commend him for sharing it and feel to not do so would have been inexcusable.
When a staring load blows up a well made rifle as a 96 Swede that needs to be relayed not suppressed.
IMO
Wulfmann
"Fools learn from their own mistakes. I learn from the mistakes of others"
Otto von Bismarck
My apologies to PA Shootist, I wish the e-mail system worked as I would have answered this in an e-mail instead. This type of response doesn't add to the answers at all but simply is justification for a statement.
If it wasn't Official and it wasn't sanctioned by Sierra as an Official release, it's anecdotal and suspicious. I am merely trying to advise caution when it comes to taking this type of story as fact. This is exactly how rumors get started. That's my only point.
Yes, IMR-4320 is too fast for the 6.5 x 55 Swede as far as my tests lead to me to conclude. When the load density doesn't make it to 85% without showing signs of higher and escalating pressure when using small incremental increases, the powder is too fast. I worked up literally dozens of loads with variations when I was trying to get a competition rifle ready which was chambered for the 6.5 x 55 Swede.
You had a conversation on the phone with a Sierra employee, who essentially related some anecdotal information to you when you were calling for professional data and consultation. Let's see...
Did Sierra investigate this incident and document that investigation?
Was this an Official Sierra announcement?
Is it available in writing from Sierra Officially?
Was there any collateral information and data from Sierra?
Was the load, the reloader, shooter and damage documented?
Or was this just buddy/buddy stuff that could possibly be covering for some reloader stupidity?
If you find it necessary to pass along unsubstantiated stories, that's your business. But without proof and an Official investigation and a release from Sierra, that's all you have.
I'm not trying to be argumentative and it isn't my intention to belittle your opinion at all but it's not an opinion, let alone factual, when you pass along unsubstantiated information, it's a story.
Since this isn't adding anything productive to the original question, that's all I'm going to write. If you want to continue this and you have my e-mail address, please feel free to contact me. I just checked and I don't have yours so I can't respond unless you contact me outside of the GB e-mail system.
Best.
The conversation was lengthy but I do not remember him asking if it could be made public and published as official data.
Do they do that with all request for load help?
What he relayed just happen to be inline with what I had found.
Now, my data has not been confirmed in any laboratory nor sanctioned by IMR or the NRA or BATFE but what I found before calling Sierra was IMR4320 had very small parameters for going from OK to pressure problems.
.5gr could difference from a flat primer to a bulging primer.
Now, again, just my observation and without official merit but no other powder has ever been so finicky.
Again only IMO, 4320 can go from safe to dangerous in short order like no other rifle powder.
The previous is based on my experience and should be considered suspect as it is only my experience and is meant purely for consideration based on your own experience as a means of sharing unofficial data.
However, any reputable company that flatly tells me they blew up a known strong gun with a published start load for a particular powder is, again, IMO, doing me a positive service for which I was and would in the future be grateful.
To have that knowledge and not share it with me would have been to my determent, but again, IMO.
Not trying to a smartarss just trying to be thorough
Wulfmann
"Fools learn from their own mistakes. I learn from the mistakes of others"
Otto von Bismarck
Wulfmann
"Fools learn from their own mistakes. I learn from the mistakes of others"
Otto von Bismarck
No one wants to see a young person intimidated by recoil. Many of us have developed reduced loads for young people and recoil sensitive shooters. The Speer reloading manuals often list a powder that is designed for reduced loads. It's reference number is SR-4759. This would work well for introduction loads while your son is developing his shooting skills.
You can also try some Accurate Arms XMR-4350.
Good Luck and let us know how it works out!
Best.
Wulfmann,
We are not disagreeing about the burn rate of the IMR-4320 in this instance.
That's why I wrote:
"When the load density doesn't make it to 85% without showing signs of higher and escalating pressure when using small incremental increases, the powder is too fast."
A low load density and rapid high pressure shifts with small or tiny increases in powder weight is an excellent indicator of a fast powder FOR THAT CARTRIDGE/BULLET COMBINATION.
"Again only IMO, 4320 can go from safe to dangerous in short order like no other rifle powder."
The same activity can be created with numerous powders in other situations. IMR-4320 is not alone in this pressure excursion. It's a matter of physics not a particular powder formulation.
Best.
The whole idea of course was to come up with a light load that would be less intimidating for my 12 year old grandson to learn to shoot his first deer rifle. I had little experience with IMR-4320, but none previously problematical. The main question was to inquire if there was some practical shelf life for gunpowders, despite being kept in good storage conditions of even modest temperatures and humidity. The net result of the inputs has lead me to have headspace checked on the rifle, a good idea in any event; to discard this old can of powder, just in case; and to follow apparent good advice about certain incompatibilities with IMR-4320 powder and the 6.5x55 Swede. I am of course familiar with the bulkier SR-4759, having used it in various older rifles for low-pressure modest velocity cast bullet loads. I'll look around for something that will fit the bill better without pressure curve problems.
On a side note, I have been reloading for dozens of calibers for over 40 years. This was the very first time that I thought I had pressure problems with a starting load from a respected reloading manual (assuming it was presure and not headspace, thus far not completely eliminated a causal factor). Thanks for all the responses.
The same activity can be created with numerous powders in other situations. IMR-4320 is not alone in this pressure excursion. It's a matter of physics not a particular powder formulation.
While that is certainly true the big difference is 4320 does it within loads it is suppose to work with.
In that it is unlike other powders.
I am not aware of any powder that with a published starting load in which as we all know, variations in humidity, temperature does slightly change burn rate etc, it can go to over pressure with the slightest variation.
I use 4895 for many loads and I can go 33 gr on a 40gr start load with no over pressure.
When you have a powder like 4320 that any atmospheric change can take it from safe to semi-dangerous, IMO, I simply avoid such a powder.
There are certainly other powders that require careful load data to remain safe but I know of no other that can be so called safe and actually not be.
Your analysis shows you are an experienced reloader and I do not disagree with your reloading opinion.
I do, however, disagree in that 4320 is unlike any powder because it can become dangerous even within known data and that should concern anyone, again, IMO
Most importantly, again IMO,I am unaware of anything that actually requires 4320 or there is not as good or better powders to use instead. Why bother?
Wulfmann
"Fools learn from their own mistakes. I learn from the mistakes of others"
Otto von Bismarck