Does anyone know who's got surplus 4895 available?
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Does anyone know who's got surplus 4895 available?
It has pretty well dried up around here.....
http://www.wideners.com/itemview.cfm?dir=278|283|313
OFC
You're about 4 years too late for original surplus IMR4895. Widener's has the British equivalent.
Don
Pretty much anything of W.W. II/Korea vintage is long gone.
Half of the surplus IMR 4895 powders I purchased went bad. I have poured out about 16 pound of surplus 4895 on the lawn. The stuff was not worth the purchase price.
Powder is deteriorating the day it leaves the factory. Nitroglycerine is mobile within the powder, and nitroglycerine and nitrocellulose want to combine to form a lower energy molecule. This is called a reduction/oxidation reaction. Nitric acid is given off as a byproduct.
I found out from an insensitive munitions expert the Army scraps double based powder ammunition at 20 years, single based 40 years. More or less, though it is based on finding it, identifying it, and then getting it to the scrap mill.
While I have used powders older than this, it is a good idea to use up your powders before they get 20 years old. I have read reports of 80's vintage IMR 4895 going bad in the can. I have some 60's/70's Bullseye that was going bad in its tin. The inside of the can was rusting, due to nitric acid gas release. The specialist mentioned powder life is confounding, some military powders going bad in 15 years, others doing well at 20.
His opinion was that surplus powder sales to the public might have been stopped due to liability reduction.
Maybe that is a good thing as pulled powder cost more than 50% of new powder. So I lost money, compared to buying new, when half my surplus IMR 4895 went bad.
Have you (all) found it to fail safe, or fail dangerous -- from the POV of pressures generated? *
*
(Realizing, of course, that failure to a Faster burn rate spells chamber pressure problems, while failure to a Slower burn spells potential problems with Op Rods, etc.))
Quote:
Originally Posted by MEHavey
The last lot I poured out on the lawn, when I shot it at 600 yards, it shot exceptionally well. However I distinctly recall differing rifle reports. More on this later. Something else, the nitric acid gas causes green corrosion on the bottom of bullets and caused case neck cracks. Most of 700 LC72 Match cases had case neck cracks. Either the case cracked before firing, or they cracked after firing. Either way nitric acid gas ruins cases.
I am currently going through a jug of surplus 4895. The stuff shoots exceptionally well and I am not allowing the powder to stay in the cases for more than a year.
I have noticed in rapid fire sequences, the occasional stiff bolt lift. I figured it was just due to powder sticking in the powder measure. Now I am not so sure.
I asked the energics expert about powder deterioration. I spent over a half hour on this topic. One of the funny things about deteriorating powder is increased “sensitivity”. Nitroglycerine (NG) migrates to the surface of the powder kernel. The surface becomes NG rich, even as the core becomes NG poor. This surface layer is “only Angstroms thick” but it is real. I was told it could be seen, I assume by scanning electron microscope. (SMES) This increase in sensitivity is also an issue in auto ignition of gunpowder..
When the surface contains more NG than the original mix, the burn rate changes. It goes up. However since the total energy content of the kernel is less, the initial pressure may spike, but the velocity out the end of the barrel won’t be all that different.
Maybe that is why I noticed funny rifle report issues on the lot that was outgassing enough nitric acid gas to corrode my bullets and crack my case necks. And it may be why I am experiencing the occasional stiff bolt lift with 168’s going at 2600 fps. Or it could be sloppy reloading techniques.
But something is going on. :dunno:
I'm using salvaged Turkish powder from WWll and have not had any problems. All my powder is stored in a cool very dry location.
I have had some experience with deteriorating powder. Following is part of a post I made with a picture a few years ago.
Below is a picture showing some cases after firing (on July 4, 2003) the 7 x 57 ammo that I loaded with BL-32 milsurp stick powder (roughly equivalent to 4895) in 1984. I recall that when I loaded the ammo in 1984 I noticed a few specks of "rust" in the powder, but it did not have an acid odor.
Case #1 Second round of 5-shot group with Remington brass, first reload, 44 gr. BL-32, 120 gr. Sierra bullet, grouped 0.52" at 50 yards. Case neck "cut" halfway through. Other four cases look OK. Average velocity was 2826 ft/sec but with 114 ft/sec extreme spread.
Case #2 First round fired with case that showed a vertical neck split before firing. Now shows some horizontal split starting at neck-shoulder junction. Winchester brass, first reload, 42 gr. BL-32, 130 gr. Speer PSP.
Case #3 Second round fired with same load. Case "lost" its neck. Apparently up the bore with the bullet.
Case #4 Third round fired with same load. Case neck stuck in forward end (note taper) of chamber. Retrieved with bronze bristle brush without difficulty.
Although scientifically interested in what was going on, I quit shooting in the interest of my own safety. I pulled the bullets of the unfired rounds and found considerable green crud in the powder and the bullet bases severely corroded. The powder had all gone bad and the cases were of course too brittle and weaked by the acidic fumes to be reused.
IMR 4895 is a single-base powder. No nitroglycerin in it! See the source information at http://hodgdon.com/PDF/MSDS%20Files/...-%20Canada.pdf
https://www.milsurps.com/images/impo.../imrmsds-1.gif
Parashooter: You are right! :super:My Lyman loading manual classifies IMR 4895 as a single base powder.
According to the expert, the Army scraps single based powders after 40 years, so the shelf life is twice that of double based powders.
I will have to ask the expert about the mechanism of deterioration for single based powders. The molecular structure he outlined were the Nitric Oxide bonds in nitrocellulose. He described how NG broke the NO double bonds in nitrocellulose. But I don’t know why the NO breaks off in the absence of NG. Maybe NC just takes longer to break down to a lower energy molecule in the absence of NG.
I have no doubt that single based powders break down releasing nitric acid. I have experienced it. The worst lot of surplus IMR 4895 turned red, smelled horribly bitter, and ate holes in cotton underwear! (Don’t ask) :runaway:
So I have more to learn.
Don't we all :o
I also am using Turkish powder from 1943 with no problems at all. The powder seems to have lasted much better than the brass!Quote:
Originally Posted by joem