"Effective Range"

[Ivy Mike]

The True Velocity (teamed with General Dynamics in the NGSW program) composite case (polymer and steel) has a steel case head in it. Combining the compliance of a well engineer polymer to form an excellent gas seal backed up by steel for the structural strength. I suspect the case will survive higher pressures than a brass case will.

Sigs case for the NGSW is a steel/brass highbred and again utilizing a steel case head it has already proven to go well over pressures all brass cases can survive.

Finally Textrons entry to the NGSW program is using case telescoping ammunition and this unique cartridge is supported in such a way as to make case strength almost irrelevant. I believe they are using and all polymer case that will easily out perform brass cases in this application due the the guns design.

and honestly, the ability of the cartridge to handle pressure is more about the chamber than anything else. Well supported chambers don't generally have kabooms.
Toss any bullet in a fire and the case will fail without generating much pressure and the bullets don't end up going anywhere with any sort of velocity. About the only drawback to polymer cases is that they are single use, but the military doesn't reload anyway.

 

[mcb]

and honestly, the ability of the cartridge to handle pressure is more about the chamber than anything else. Well supported chambers don't generally have kabooms.
Toss any bullet in a fire and the case will fail without generating much pressure and the bullets don't end up going anywhere with any sort of velocity. About the only drawback to polymer cases is that they are single use, but the military doesn't reload anyway.

Except in this case the performance requirements the Army has put on the ammo/bullet for the NGSW is forcing pressures in these new cartridges into the 80-90 kpsi range. At those pressures even a well supported case made of brass starts to flow. The brass even if it does not rupture flows into and small gaps like extractor pockets, ejector holes, etc causing functional issues, especially in a semi/full-auto. The move away from brass cases is being driven by the ammo performance requirement as much as any other desire to reduce weight and cost.

 

[David Hoback]

The True Velocity (teamed with General Dynamics in the NGSW program) composite case (polymer and steel) has a steel case head in it. Combining the compliance of a well engineer polymer to form an excellent gas seal backed up by steel for the structural strength. I suspect the case will survive higher pressures than a brass case will.

Sigs case for the NGSW is a steel/brass highbred and again utilizing a steel case head it has already proven to go well over pressures all brass cases can survive.

Finally Textrons entry to the NGSW program is using case telescoping ammunition and this unique cartridge is supported in such a way as to make case strength almost irrelevant. I believe they are using and all polymer case that will easily out perform brass cases in this application due the the guns design.

Yes.....I’ve read all their articles as well. Luckily, I don’t rely on what companies looking to make a buck, have to say to find truth. I’ll wait for real world testing. I’m still skeptical. There is a reason certain things are NOT made of polymer. And understand...I’m a plastic fan. I listened, as a child, to my father embellish his Colt45 “being able to tear a man’s arm off being hit!”, and, “if ya run out of ammo, you can club him over the head with it!” LOL! No, I’m no “ONLY Metal & Wood”, 1911 FUDD! Always been a fan of polymer. But we shall see if these cases can withstand near 60K PSI pressures. I foresee lower pressure(hence, velocity), and accuracy not worth repeating. Oh, and at the very least, although they LOVE throwing out how “recyclable” the stuff is(I guess to please APC, the squad and other Greenpeace warriors in Washington), won’t be able to reload them. So, no thanks.