Saw there are now patents awarded for MIM stainless steel cases that are 30% lighter than brass and tolerate up to 100kpsi.
MIM Cases
- Thread starter Vynz
- Start date
Interesting. And thanks for sharing.
But... isn't the high temp range pretty low ?
"Durable stainless steel case material with reliable functionality from -54ºC to 107ºC"
Conversion to fahrenheit shows about 224.6 degrees ... so just over boiling water ?
Someone correct me if I am wrong, but don't 5.56 cases , freshly fired / cold barrel, come out at about at about 300+ degrees ?
I would imagine from a hot chamber , the fired brass would be much hotter.
But... isn't the high temp range pretty low ?
"Durable stainless steel case material with reliable functionality from -54ºC to 107ºC"
Conversion to fahrenheit shows about 224.6 degrees ... so just over boiling water ?
Someone correct me if I am wrong, but don't 5.56 cases , freshly fired / cold barrel, come out at about at about 300+ degrees ?
I would imagine from a hot chamber , the fired brass would be much hotter.
Think more along the lines of being able to operate in Antarctica as well as the Sahara.
WTF?
”United States Patents 11465207 and 11493314 are intended to protect the US government’s ability to organically produce and supply this technology to the warfighter but allow cost reduction and maturation through private commercialisation.”
”organically”?
“commercialization”!
As to reloading Stainless Steel?
-Richard
”United States Patents 11465207 and 11493314 are intended to protect the US government’s ability to organically produce and supply this technology to the warfighter but allow cost reduction and maturation through private commercialisation.”
”organically”?
“commercialization”!
As to reloading Stainless Steel?
-Richard
Thank you... my predisposed distrust of current tech. MIM products reared its ugly head.
MIM gets a bad rap. Done right it can be an excellent way to produce. Done wrong and well...I think we know.
Process engineering matters.
Looks like they use MIM 17-4 stainless steel.
Here's some info on it...
https://www.zcmim.com/mim-17-4/
17-4 PH is said to have good mechanical properties up to 600 deg F. I wonder if this holds true for MIM 17-4?
Here's some info on it...
https://www.zcmim.com/mim-17-4/
17-4 PH is said to have good mechanical properties up to 600 deg F. I wonder if this holds true for MIM 17-4?
I am obviously not a reloader so I’m going to ask stupid questions.
Would the higher 100kpsi pressures mean people could safely load hotter versions of current cartridges?
If hotter versions were possible would they only be possible in specific rifle types like only Rem700 style bolts or AR bolts or AK/XCR bolts?
Would these cases require a whole new reload book distinct from brass?
Would the higher 100kpsi pressures mean people could safely load hotter versions of current cartridges?
If hotter versions were possible would they only be possible in specific rifle types like only Rem700 style bolts or AR bolts or AK/XCR bolts?
Would these cases require a whole new reload book distinct from brass?
the operating range being quoted I would assume is not for "retains mechanical properties" but describes the ambient environment where the cases will function reliably without issue. Metal expands when heated and different metals expand at different rates, at consistent very high temperatures with the thinner stainless material I would expect it to essentially 'stick' itself hard to the chamber as a result of expanding faster than the barrel/barrel extension. That however takes more time than the normal firing process, but does give me some concerns for use in arms with a high fire rate, time will tell.
as far as full mechanical properties, as with anything engineering, the answer is "It Depends" in this case the real issue is the material thickness posing the greatest challenges. References like you linked are generally done using standardized "test coupons" that are described in the relevant testing standard, and are usually thicker than rifle case material.
I would expect that as long as the process spec for this MIM is properly followed, the resulting cases should live up to the billing.
1) yes, as is already being done with SIG bimetals by myself and others
2) the problem with higher pressure isn't just barrel integrity, but the bolt thrust the locking lugs are designed to contain. most modern manufactured arms are designed with a very high safety factor, and shouldn't really be a huge concern, but I would be wary about doing so with anything manufactured before about 1985 (for several reasons)
3) very likely. the brass recipies should work fine as long as you ensure case volume is similar, but the reverse will not be true. Think of how we currently treat brass 'cowboy' and 'military spec' loads for older firearms today.
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