New Injection-Molded Stainless Cartridge Cases

[BluntForceTrauma]

OK, got a heads up from a member here and THIS is EXACTLY what we've been needing for my dream assault rifle cartridge.

Link to Concurrent Technologies Corporation (CTC) announcement of patent on injection-molded stainless-steel cartridge cases HEREHERE.

Anybody as excited as I am or meh?

[lazyengineer]

Neat, I guess? Aside from better corrosion resistance under long term harsh duty storage, what advantage does this have over lacquer coated steel?

My concern is that it will increase the cost, but also, I'm not sure if bare ferrous metal on barrel chamber ferrous (apparently it's still magnetic) metal is going to be better or worse for gas sealing and for releasing than lacquer coated is going to be?

Though, one challenge with laquor seems to be that not enough soot sticks to it, allowing soot to build in the chamber and then create problems. Which is why I run a few rounds of brass in the bottom of my last mag, when I do a steel outing, to pull that out. So maybe the stainless has similar properties in that regard, as brass does?

[grayfox]

[grayfox]

[BluntForceTrauma]

Aside from better corrosion resistance under long term harsh duty storage, what advantage does this have over lacquer coated steel?

Don't know the technicals details. Maybe strength? Maybe ease of creating other cartridges? Maybe cost?

[lazyengineer]

Don't know the technicals details. Maybe strength? Maybe ease of creating other cartridges? Maybe cost?

In general carbon steel is considered to be stronger than stainless, so not sure about strength. But if this has the spring-back better than carbon steel, that would be big.

[grayfox]

Their website says it is a MIM process, and the case is lighter, stronger, thinner, etc...
So possibly using SS in this process gives better results than plain carbon steel.
Extra corrosion resistance (inside and out) is probably also a plus. There is some % humidity even inside the case, what, 45% or so?

Wonder how reloadable it is. Brass expands out/back but also conforms out to the chamber length at the shoulder... this is useful not only in sealing but also makes up for chamber length tolerances. What would the SS do? Plus how if anything does the "flash" heating during firing affect the material properties.

It should result in a longer lasting primer pocket.

[just_john]

I work for a company that builds heavy process control equipment for refineries and power plants. We build most of it our of stainless steel. For case heads where the thickness is significant relative to OA size is a reasonable thing to do. But when you go to thinner material, a lot of strange ( unpleasant ? ) things happen. Stainless has very poor heat transfer capabilities so it will warp and twist badly. I could envision cases becoming so stuck that serious machine work becomes required to remove the case. Stainless is also very brittle so upon firing, the necks may split before they seal the throat of a chamber. Probably not a good idea to make the entire case from stainless.

[JASmith]

The advantage to stainless MIM is greater allowable operating pressure before the case head strart flowing out of the unsupported area near the bolt.

There is a current threat discussing bolt breakage. Going from ~50 ksi max to ~ 80 ksi max just might break a few bolts.